GPZ600R Won't Start - Compression Issue
Rabbit
I have a 1985 GPZ600R that doesn’t want to start. I put it away just
before Xmas and it wouldn’t start again in January. I have charged the
battery, put a backup one in parallel, cleaned out the carbs, put new
fuel in the tank, tested the spark (big blue spark when against
engine), replaced the spark plugs, checked the engine isn’t seized
(can be turned over from rear wheel in top gear). I have also tried
using brake cleaner, carb clearner and easy-start in the engine with
the air filter removed. It currently turns over but does catch/start.
I am convinced the ignition is OK as the spark looks healthy.
Similarly, I believe it is getting fuel as I can smell fuel from the
exhaust pipes and it goes bang/backfires if I try to start it for too
long.
I have not checked the exhaust for any obstructions but can’t see how
this could happen it has been stored in a garage). I haven’t checked
the timing, alternator, starter motor, CDI or reg-rec but don’t see
how they could be an issue. I have I also haven’t tried bump starting
it as it is flat where I live and I don’t think I’d get enough speed
up. I ran a compression test this evening:
Compression Test
Method: Ran the engine cold and with a Wide Open Throttle (WOT). I
used another battery in parallel with the bike battery to ensure there
was enough power. Tested each cylinder 3 times and then moved onto the
next from 1 to 4 (left to right). To ensure the numbers were reliable
I then retested the cylinders (again from 1 to 4). As the readings
were very low for cylinders 3 and 4 I put a bit of oil in these
cylinders and took 2 new readings. When taking the readings I did so
after about 8-10 cycles as it was usually still rising after about 5
or 6. My results (all in psi) are as follows:
Cylinder 1 – 138, 138, 142 – Average 139
Cylinder 1 Retest – 140
Cylinder 2* – 130, 122, 135 – Average 129
Cylinder 2 Retest – 142, 140, 145 – Average 142
Cylinder 3 – 80, 82, 89 – Average 84
Cylinder 3 Retest – 91
Cylinder 3 with Oil – 108, 110 – Average 109
Cylinder 4 – 30, 29, 30 – Average 30
Cylinder 4 Retest – 35
Cylinder 4 – 48, 48 – Average 48
* On cylinder 2 I originally recorded 90, 100 and 105 but then changed
to another backup battery as it was running out of juice. The fresh
battery gave the numbers given above. Why does the strength of the
battery affect the compression reading? Is it due to the greater
inertia of a faster moving piston?
In summary:
Cylinder 1 – 139psi
Cylinder 2 – 129psi
Cylinder 3 – 84psi
Cylinder 4 – 30psi
As I understand it this could mean three things:
1) The head gasket has failed on the right-hand side of the engine as
the values slope that way. Could this be due to the bike being parked
on its side-stand for an extended period (oil starvation of some
kind)?
2) The piston rings in cylinders 3 and 4 are worn and require
replacing.
3) Adding oil to cylinders 3 and 4 did not bring back sufficient
compression, so a valve service (lapping valves to give a better seal)
is required. Would adjusting the valve clearances give any benefit?
Can anyone confirm my diagnosis and recommend where to go from here? I
imagine a leak-down test would be beneficial to pin point the exact
source of the lack of compression.
Any advice would be much appreciated. Thanks.
Bill Vanek
wrote:
You're right that a leak-down test it the next step. Anyway, if it's
valves, if it has hydraulic lifters, it could be insufficient oil
pressure to the lifters to open the valves. If that's the case there
will be no leak-down. Maybe excessive oil pressure holding them open.
Maybe deposits on the valve stems, again holding the valves open. Did
you check the oil level? Is it good oil? Also, did it run okay the
last time it did run?
The Older Gentleman
> I have a 1985 GPZ600R that doesn't want to start. I put it away just
> before Xmas and it wouldn't start again in January. I have charged the
> battery, put a backup one in parallel, cleaned out the carbs, put new
> fuel in the tank, tested the spark (big blue spark when against
> engine), replaced the spark plugs, checked the engine isn't seized
> (can be turned over from rear wheel in top gear). I have also tried
> using brake cleaner, carb clearner and easy-start in the engine with
> the air filter removed. It currently turns over but does catch/start.
> I am convinced the ignition is OK as the spark looks healthy.
> Similarly, I believe it is getting fuel as I can smell fuel from the
> exhaust pipes and it goes bang/backfires if I try to start it for too
> long.
<Snip the rest>
One cylinder does look rather low, and one looks worryingly low, but it
should start anyway.
Your problem is stale fuel in the carbs; jellied fuel that's blocking
key passageways and jets.
If you dismantled the carbs yourself to clean them, the chances are you
made the problem worse unless you *really* know what you're doing.
And this:
>Why does the strength of the battery affect the compression reading? Is
it due to the greater inertia of a faster moving piston?
makes me worry. As does your worry that leaving a bike on a sidestand
could cause a head gasket to fail.
Look, get SWK to strip down the carbs properly. Best solution is
ultrasonic cleaning, but proper professional-style cleaning plus
cleaning out all the jets with tiny strands of copper wire and lots of
compressed air will, if you're patient, do the job.
Don't start tearing down the engine.
--
BMW K1100LT Ducati 750SS Honda CB400F Triumph Street Triple
Suzuki TS250ERx2 GN250. Only seven bikes now.
Try Googling before asking a damn silly question.
chateau dot murray at idnet dot com
The Older Gentleman
Learn to snip....
> You're right that a leak-down test it the next step. Anyway, if it's
> valves, if it has hydraulic lifters, it could be insufficient oil
> pressure to the lifters to open the valves. If that's the case there
> will be no leak-down.
Someone with this much ignorance of the bike in question shouldn't
really be trusted, IMHO.
> Maybe excessive oil pressure holding them open.
> Maybe deposits on the valve stems, again holding the valves open.
Not a problem since about 1920.
>Did
> you check the oil level? Is it good oil? Also, did it run okay the
> last time it did run?
<Holds head>
Bill Vanek
Older Gentleman) wrote:
>Bill Vanek <bilv...@invalid.com> wrote:
>
>Learn to snip....
>
>
>> You're right that a leak-down test it the next step. Anyway, if it's
>> valves, if it has hydraulic lifters, it could be insufficient oil
>> pressure to the lifters to open the valves. If that's the case there
>> will be no leak-down.
>
>Someone with this much ignorance of the bike in question shouldn't
>really be trusted, IMHO.
So I guess you missed the "if" in my reply?
>> Maybe excessive oil pressure holding them open.
>> Maybe deposits on the valve stems, again holding the valves open.
>
>Not a problem since about 1920.
It still happens on cars, so why not bikes? Reminds me of the
"ignorance" comment.
>>Did
>> you check the oil level? Is it good oil? Also, did it run okay the
>> last time it did run?
>
><Holds head>
As am I. Sarcasm work best if you know what you're talking about.
Bill Vanek
Older Gentleman) wrote:
>One cylinder does look rather low, and one looks worryingly low, but it
>should start anyway.
>Your problem is stale fuel in the carbs; jellied fuel that's blocking
>key passageways and jets.
That explains what is essentially no compression in one cylinder? That
is an issue that needs to be addressed, don't you think? BTW, if you
had actually read the initial post, he said the bike sat for about a
month - that's all. Stale fuel? That's an interesting theory.
>Look, get SWK to strip down the carbs properly. Best solution is
>ultrasonic cleaning, but proper professional-style cleaning plus
>cleaning out all the jets with tiny strands of copper wire and lots of
>compressed air will, if you're patient, do the job.
Right, that should get the compression back up.
As they say, when the only tool you have is a hammer, every problem
looks like a nail. I guess when you have some special carb cleaning
aptitude, that's where the diagnosis always leads.
paul c
I'd agree about the compression being a bit of a red herring, ie., if
everything else is okay it should start even though it would probably
run roughly. (eg., it should start even if the carb to cyl #4 is
blocked off.) But the OP didn't state whether he has ever been able to
start it so for all we know the plug wires are connected to the wrong
cylinders or the carbs are massively out-of-sync or the choke/enrichener
is not adjusted or a few other things. I'd say the only useful result of
a leak-down test, at least as far as getting the engine started is
concerned, would be to confirm that the valve timing hasn't been
reversed by somebody who's had it apart. The OP did say he had clean
gas but as you suggest the slow jets could still be blocked or the carbs
seriously mis-assembled after cleaning (the OP didn't say whether the
carbs are the slide type or CV type but either way it's not hard to muck
things up when there are four of them). Also, he didn't say whether he
had spark on the cylinders that have decent compression. Still, I'd
agree that it is kind of a waste of time to do a leak-down test when the
immediate problem is getting the engine started.
The Older Gentleman
> That explains what is essentially no compression in one cylinder? That
> is an issue that needs to be addressed, don't you think? BTW, if you
> had actually read the initial post, he said the bike sat for about a
> month - that's all. Stale fuel? That's an interesting theory.
It seems to be the case. nine times out of ten, when somebody has left a
carb-fed[1] bike sitting for months without using it. A simple Google of
this and other groups will show you that.
>
> >Look, get SWK to strip down the carbs properly. Best solution is
> >ultrasonic cleaning, but proper professional-style cleaning plus
> >cleaning out all the jets with tiny strands of copper wire and lots of
> >compressed air will, if you're patient, do the job.
>
> Right, that should get the compression back up.
The compression isn't the issue here. It really, really isn't.
>
> As they say, when the only tool you have is a hammer, every problem
> looks like a nail. I guess when you have some special carb cleaning
> aptitude, that's where the diagnosis always leads.
I don't. But I've got a bit more experience with bikes than you have.
[1] Less of an issue with FI. I wonder if you can work out why?
The Older Gentleman
> >Someone with this much ignorance of the bike in question shouldn't
> >really be trusted, IMHO.
>
> So I guess you missed the "if" in my reply?
If (hah!) you have to speculate, you *really* don't know what you're
talking about.
>
> >> Maybe excessive oil pressure holding them open.
> >> Maybe deposits on the valve stems, again holding the valves open.
> >
> >Not a problem since about 1920.
>
> It still happens on cars, so why not bikes? Reminds me of the
> "ignorance" comment.
It is *such* a rare thing to happen on bikes built in the last 30 years.
The 'excessive oil pressure' thing we can safely discount. You're not
doing well here.
Apply Occam's Razor. The bike has been sitting for nearly four months.
It's reasonable to assume it was running before "it was put away", or
the OP would have said "it hasn't run since x", but it's not a given, I
grant you. Still, if it has been sitting for *longer* that only makes
the stale fuel likelihood even more likely.
> >>Did
> >> you check the oil level? Is it good oil? Also, did it run okay the
> >> last time it did run?
> >
> ><Holds head>
>
> As am I. Sarcasm work best if you know what you're talking about.
And you don't. Now, apologies for being curt, but there are times and
places when...
Futility Man
engine actually has hydraulic lifters? If we're dealing with solid lifters and
adjustable tappets, it's entirely possible that two cylinders have tight valves
causing low compression.
And it's entirely possible that it was left sitting with 10% ethanol fuel in the
carbs, which has dried out and left the idle circuits plugged. Many bikes will
not start if the throttle is not at idle position (none of mine will), so if the
idle circuit is plugged, it's not going to start at idle position and opening
the throttle during cranking will not help.
It would help if Rabbit would come back and tell us exactly what he did when he
"cleaned out the carbs".
--
Futility Man
The Older Gentleman
> All sniping and lack of snipping aside, have we determined whether or not
> this engine actually has hydraulic lifters?
FFS. Yes, we have. It doesn't.
>If we're dealing with solid lifters and adjustable tappets, it's
>entirely possible that two cylinders have tight valves causing low
>compression.
Irrelevant here due to above.
>
> And it's entirely possible that it was left sitting with 10% ethanol fuel
> in the carbs, which has dried out and left the idle circuits plugged.
> Many bikes will not start if the throttle is not at idle position (none of
> mine will), so if the idle circuit is plugged, it's not going to start at
> idle position and opening the throttle during cranking will not help.
Yes, you're right on the money here. Ethanol fuel or not, the carbs are
gunged.
> It would help if Rabbit would come back and tell us exactly what he did
when he
> "cleaned out the carbs".
And on the money here, too.
The Older Gentleman
<snip>
Just for the record, a minuscule percentage of Japanese bikes have or
have had hydraulic tappets.
A few big cruisers and HD-wannabes. I think later iterations of the Gold
Wing did. And the Honda CBX750 and its variants (Nighthawk, etc) did. A
tiny, tiny percentage.
Mark Olson
> All sniping and lack of snipping aside, have we determined whether or not this
> engine actually has hydraulic lifters? If we're dealing with solid lifters and
> adjustable tappets, it's entirely possible that two cylinders have tight valves
> causing low compression.
It most defintely does not have hydraulic lifters or lash adjusters. Without
looking at the fiche, it's either screw and locknut adjusters or shim under
bucket... OK I cheated, it's screw and locknut, and the forked rockers look
identical (but they're not) to the ones used on my ZG1000. It's possible that
the clearances closed up and the the valves burned, I suppose.
> And it's entirely possible that it was left sitting with 10% ethanol fuel in the
> carbs, which has dried out and left the idle circuits plugged. Many bikes will
> not start if the throttle is not at idle position (none of mine will), so if the
> idle circuit is plugged, it's not going to start at idle position and opening
> the throttle during cranking will not help.
Very likely. As others have said, while the low compression on #4 is a concern,
presumably when it was put away it did run, however poorly.
Since I do have a homemade leakdown tester, I would definitely use it, but they are
available to all, for not too much money (< $40) at your local cheap chinese crap
store, and using one will definitely help to find where the compression is being
lost:
http://www.harborfreight.com/cylinder-leak-down-tester-94190.html
> It would help if Rabbit would come back and tell us exactly what he did when he
> "cleaned out the carbs".
Agreed.
Kevin Bottorff
news:mk4up61jjhab6b2dk...@4ax.com:
> On Fri, 8 Apr 2011 07:18:44 +0100, totallyde...@yahoo.co.uk (The
> Older Gentleman) wrote:
>
>>Bill Vanek <bilv...@invalid.com> wrote:
>>
>>Learn to snip....
>>
>>
>>> You're right that a leak-down test it the next step. Anyway, if it's
>>> valves, if it has hydraulic lifters, it could be insufficient oil
>>> pressure to the lifters to open the valves. If that's the case there
>>> will be no leak-down.
>>
>>Someone with this much ignorance of the bike in question shouldn't
>>really be trusted, IMHO.
>
> So I guess you missed the "if" in my reply?
>
>>> Maybe excessive oil pressure holding them open.
>>> Maybe deposits on the valve stems, again holding the valves open.
>>
>>Not a problem since about 1920.
>
> It still happens on cars,
In my 30 years working on cars NEVER has a deposit on a valve stem held a
valve open. carbon on the valve face yes, stem Not a chance. KB
The Older Gentleman
> t's possible that
> the clearances closed up and the the valves burned, I suppose.
If the clearances haven't been checked for yonks, yes. Or if someone
cocked up the adjustment. As you imply, though, the low compression is a
red herring here.
It's the carbs. It's always the carbs.
Kevin Bottorff
news:1jzf5x9.1md8gt41uqghc5N%totallyde...@yahoo.co.uk:
> Futility Man <nu...@futile.org> wrote:
>
>> All sniping and lack of snipping aside, have we determined whether or
>> not this engine actually has hydraulic lifters?
>
> FFS. Yes, we have. It doesn't.
>
>>If we're dealing with solid lifters and adjustable tappets, it's
>>entirely possible that two cylinders have tight valves causing low
>>compression.
>
> Irrelevant here due to above.
>
>>
>> And it's entirely possible that it was left sitting with 10% ethanol
>> fuel in the carbs, which has dried out and left the idle circuits
>> plugged. Many bikes will not start if the throttle is not at idle
>> position (none of mine will), so if the idle circuit is plugged, it's
>> not going to start at idle position and opening the throttle during
>> cranking will not help.
>
> Yes, you're right on the money here. Ethanol fuel or not, the carbs
> are gunged.
>
>> It would help if Rabbit would come back and tell us exactly what he
>> did
> when he
>> "cleaned out the carbs".
>
> And on the money here, too.
>
>
your so sure its the carbs, why won`t it start on either then, he did
say he tried it!!!!!!!!!!!!!!! doen`t make sence to me. KB
The Older Gentleman
> your so sure its the carbs, why won`t it start on either then, he did
> say he tried it!!!!!!!!!!!!!!! doen`t make sence to me.
No, I'm sure it doesn't. Don't lose sleep over it.
`
> 3) Adding oil to cylinders 3 and 4 did not bring back sufficient
> compression, so a valve service (lapping valves to give a better seal)
> is required. Would adjusting the valve clearances give any benefit?
By all means, check the valve clearances before you remove the
cylinder head to do a valve job.
The 600 Ninja has simple screw type valve adjusters, so you don't need
to remove the camshafts to adjust valve clearances.
Did the engine smoke on start up and stop smoking after it warmed up
before you stored it for the winter?
Smoking on start up is a symptom of leaky valve guide oil seals and
oil that leaks down onto the valve head will turn into wet carbon that
will block the intake valves from closing, thereby causing a loss of
compression.
The exhaust valves run a lot hotter than the intakes, so they burn oil
off the heads of the valves.
But my GS1100's intake valves actually burned and pitted because of
leaky valve guide oil seals.
The easiest way to remove this carburized oil from the valve heads is
by a *shock treatment* of Techron Concentrate in the gasoline.
Techron is a copper chemical that prevents carbon from attaching
itself to the intake valves.
Futility Man
Gentleman) wrote:
>As you imply, though, the low compression is a
>red herring here.
True, but it's another strike against the engine starting without correcting
anything. If either of those two cylinders have a functioning idle circuit, it
would help if they had any compression.
>It's the carbs. It's always the carbs.
Unless it's something else. Crosswired, a mixture of brake cleaner, ether, and
Ged knows what else sprayed into the intake, tight valves (not necessarily
burned - yet) ... ;-) Head gaskets don't normally fail sitting in a garage.
One of the hardest to correct operator errors I ever saw was on my own bike, a
Suzuki DR250. Someone who should know better was trying to start it by rolling
on the throttle as he thumbed the starter. Got it so flooded I ran the battery
down trying to correct it and had to bump-start it, it rolled a good 100 yards
before it ever fired. When I got it back to the house, he said "Interesting
starting procedure. What do you do when you're not on top of a hill?" I shut
off the ignition, turned it back on, and touched nothing but the start button.
Fired right up.
RABBIT? What exactly, step by step, did you do when you cleaned out the carbs?
Did you take the whole carb bank off the engine? Did you separate the carbs
from each other? Did you have any parts left over? Have you had more than one
plug wire off at a time?
--
Futility Man
Keith
> On Fri, 8 Apr 2011 07:18:45 +0100, totallydeadmail...@yahoo.co.uk (The
>
> Older Gentleman) wrote:
> >One cylinder does look rather low, and one looks worryingly low, but it
> >should start anyway.
> >Your problem is stale fuel in the carbs; jellied fuel that's blocking
> >key passageways and jets.
>
> That explains what is essentially no compression in one cylinder? That
> is an issue that needs to be addressed, don't you think? BTW, if you
> had actually read the initial post, he said the bike sat for about a
> month - that's all. Stale fuel? That's an interesting theory.
Yep the compression is a worry BUT it wont keep it from starting.
Stale fuel? Interesting theory? Sir you are either sarcastic or a
blithering idiot...frankly from what you've posted so far I'm inclined
to believe the latter and call bullshit if you claim the former.
>
> >Look, get SWK to strip down the carbs properly. Best solution is
> >ultrasonic cleaning, but proper professional-style cleaning plus
> >cleaning out all the jets with tiny strands of copper wire and lots of
> >compressed air will, if you're patient, do the job.
>
> Right, that should get the compression back up.
The compression means fuck all if it isn't running.
> As they say, when the only tool you have is a hammer, every problem
> looks like a nail. I guess when you have some special carb cleaning
> aptitude, that's where the diagnosis always leads.
And you madam are a TOOL.
Keith
Oh shut the fuck up you idiot...
The Older Gentleman
> Oh shut the fuck up you idiot...
Cruel but succinct and accurate.
The Older Gentleman
> >It's the carbs. It's always the carbs.
>
> Unless it's something else.
It's the carbs. Gummed up, and he didn't clean them properly. Or worse
still, buggered them further in trying to clean them.
`
wrote:
> Oh shut the fuck up you idiot...
Try and make me shut up, you retarded midget.
Rabbit
and to answer some of your questions:
1) The oil level is in the middle of the range of LOW – HIGH.
2) It is OK oil, not the most expensive and hasn’t been changed in
about a year.
3) It ran fine the last time it was out (and the time before that), no
issues. It does occasionally die once warmed up or kinda bog down and
won’t go past about 4kRPM ish. Then after a while it clears itself and
all is fine again (accompanied by some smoke out the exhaust).
4) I don’t believe it is stale fuel as I put brand new fuel in about a
month ago when I cleaned the carbs out. I also fitted an in-line fuel
filter at the same time.
5) I’ve stripped GPZ carbs about 3 times over the years, when I
suspect a fuel issue, and it has always run fine afterwards. This time
it has not but I believe I’m competent at the job. I did a more
thorough job than what I have seen mechanics do, which is a quick
spray of all the bits with carb cleaner and air hose. They are CV
carbs.
6) When I cleaned out the carbs I completely disassembled them,
cleaned out all the jets, passageways, etc will carb cleaner (the idle
jets were clogged). This includes all the little passageways, float
bowls, etc. Everything was very clean going back together, adjusted to
the settings they were at previously. Everything that needed it was
oiled (eg, throttle spring). Throttle butterflies were adjusted so
that they all open at exactly the same time.
7) I don’t believe leaving a bike on its side-stand will cause head
gasket failure, that would be ridiculous. I thought it may be a
contributing factor. Perhaps there was moisture around the engine that
freezed/thawed over the sub-zero winter. I don’t know, just thought it
might be a useful question.
8) My method to getting it started: Iginition (got good spark with
charged battery and new plugs), fuel (think this is OK due to new
fuel, smell of fuel, cleaned out carbs, in-line filter and it won’t
start n brake cleaner), so then looked at compression (found 2 low
pressure cylinders).
9) The valve clearances were adjusted by a garage about a year ago.
10) Have checked the HT leads go to the correct plugs, even double
checked with the wiring diagram.
11) Had a strong spark on all 4 cylinders.
Hope this helps. :)
`
> 1) The oil level is in the middle of the range of LOW – HIGH.
Low oil level will not affect whether or not the engine starts.
> 2) It is OK oil, not the most expensive and hasn’t been changed in
> about a year.
The quality of engine oil will not affect whether or not the engine
starts.
> 3) It ran fine the last time it was out (and the time before that), no
> issues. It does occasionally die once warmed up or kinda bog down and
> won’t go past about 4kRPM ish.
That tends to indicate a carburetor problem.
> Then after a while it clears itself and
> all is fine again (accompanied by some smoke out the exhaust).
Bluish white smoke coming at the exhaust indicates that the rings
aren't sealing or that the valve guide oil seals are leaking.
If the rings aren't sealing, the engine will smoke all the time.
Valve guide oil seals leak so little oil it collects in the combustion
chamber and burns off when the engine is first started.
Oil smoke is thick and it hangs around for a while.
White smoke that rises from the exhaust pipe and dissipates rapidly is
either condensation of coolant leakage into the combustion chamber.
If two adjacent cylinders have low compression that might indicate a
leaky head gasket, and a leak down test would prove if that was the
case.
> 4) I don’t believe it is stale fuel as I put brand new fuel in about a
> month ago when I cleaned the carbs out.
An engine will start just fine on stale fuel. I've started engines
that had gasoline in the tank that was two or three years old.
The volatile fractions that help keep carburetors clean and non-
polluting also cool the combustion process and when the additives are
gone the engine will ping when it gets really hot.
> 5) They are CV carbs.
One of the problems that confuses newbies is that CV carburetors don't
have a real plate type choke. They have cold starting enricher valves
which are opened when the "choke" lever or knob is moved to the ON
position.
The enricher valves are AIR valves which bypass the throttle
butterflies.
Air flow through the enricher passages causes enough vacuum to suck
fuel directly out of the float bowls.
But the throttle butterflies must be completely CLOSED when cranking
the engine with the electric starter.
One trick is to turn the master idle knob all the way
*counterclockwise* so the throttle butterflies are not open the least
little bit.
The engine should start and idle on the fuel air mixture which comes
through the cold start enricher circuit, even on a cold day, if the
enricher valves are fully open.
However, the starter jet is a hole in the bottom of the float bowl. I
hope you squirted carburetor cleaner through all the starter jets in
the float bowls.
> 6) When I cleaned out the carbs I completely disassembled them,
> cleaned out all the jets, passageways, etc will carb cleaner (the idle
> jets were clogged). This includes all the little passageways, float
> bowls, etc. Everything was very clean going back together, adjusted to
> the settings they were at previously. Everything that needed it was
> oiled (eg, throttle spring). Throttle butterflies were adjusted so
> that they all open at exactly the same time.
Like I said above, turn the master idle knob all the way
counterclockwise and apply full "choke" and don't twist the throttle
when trying to start the engine.
Sometimes I've found it necessary to hand choke the carburetors by
putting the palm of my hand over the inlet of each carburetor in order
to get the engine vacuum to suck fuel up into the idle jets and idle
passages.
The last time I had to do that, the engine hadn't been run for 4 years
and I removed the carbs and cleaned them thoroughly.
There wasn't a lot of gum and varnish in the carbs, but the engine
just wouldn't start until I hand choked each carburetor.
`
London) wrote:
> Keith <stevenkei...@hotmail.com> wrote:
> > Oh shut the fuck up you idiot...
>
> Cruel but succinct and accurate.
Go jump off of Tower Bridge, you stupid cocksucker.
paul c
When you say it 'ran fine' at one time, I presume that it was generally
startable and rideable, even though not as powerful as it would be with
four good cylinders. Regarding points 3) and 6), it does seem that the
immediate starting problem is related to air/fuel mixture which is
pretty crucial (ie., roughly speaking, if the ratio is less than approx
12:1 or more than 17:1, it will probably be impossible to start):
a) Perhaps there are leaks in the intake manifold, especially if it's
the rubber kind that deteriorates with age and also can easily get
distorted with repeated carb removal and installation. Sometimes this
results in the low speed symptoms mentioned in point 3). If so, the
carbs might well have been adjusted rich in the past to make it run but
the leak is just getting worse. If there is a manifold air leak you
might find that turning the idle screws out even further will make it
start, although it won't idle very well once it's warm - this would give
further evidence of an air leak. Hard to find an air leak unless you
can get the engine started. I'd also double-check that the enrichment
circuit or choke (whichever these carbs use) is on. If there is a choke
plate on the air side that could be checked visually, if enrichener
passage you'd need to blow air or fluid through the carb orifices to be
sure. If one or more carbs has an accelerator pump that might need
checking to (usually service manuals say how). I forget the name but
sometimes there's another device on carbs that shuts off fuel when the
throttle is released at speed to avoid backfires.
(Possibly a leak-down test could show a manifold air leak but I'm not
sure it would be easy to notice in this case since we already have some
leaking cylinders.)
b) I would also double-check the idle mixture screws (slow jet) against
factory settings (ie., number of turns out), if you can find a reference
for that. Also make sure each one of the screws still has its spring,
washer and o-ring intact. Similarly for the floats (ie., level).
c) In spite of the apparent good visual spark, in case the ignition
components are marginal/weak, I'd try to set the spark gap to the narrow
side of the recommended range which might help in at least getting it
started so that you spray the manifold to see if it's leaking. Cross
your fingers that it's not just pickup coils going down hill because
that's a little harder to diagnose.
I'm pretty sure that most any of the Japanese four-cylinder bikes will
run after a fashion with only two good cylinders and can usually be
started in a couple of tries.
paul c
...
>> 5) They are CV carbs.
>
> One of the problems that confuses newbies is that CV carburetors don't
> have a real plate type choke. They have cold starting enricher valves
> which are opened when the "choke" lever or knob is moved to the ON
> position.
Minor point - at least a few CV carbs do have a 'plate' choke, eg., the
ones on the 1982 DOHC CB750's.
paul c
All good points from what I've seen. (It took me a long time to learn
to ignore the advice of neighbours to try to start with WOT. Amazing
how so many people think a high-speed engine throttle setting is better
for starting which is necessarily done at low speed.)
Also, with four carb bowls, if they've just been installed after
cleaning, it can take ten or more start attempts just to get the bowls
filled with fuel.
Bill Vanek
Older Gentleman) wrote:
>Bill Vanek <bilv...@invalid.com> wrote:
>
>> >Someone with this much ignorance of the bike in question shouldn't
>> >really be trusted, IMHO.
>>
>> So I guess you missed the "if" in my reply?
>
>If (hah!) you have to speculate, you *really* don't know what you're
>talking about.
I was talking about engines in general, not motorcycle engines. I was
an auto mechanic.
>> >> Maybe excessive oil pressure holding them open.
>> >> Maybe deposits on the valve stems, again holding the valves open.
>> >
>> >Not a problem since about 1920.
>>
>> It still happens on cars, so why not bikes? Reminds me of the
>> "ignorance" comment.
>
>It is *such* a rare thing to happen on bikes built in the last 30 years.
Something changed here. It was not 1920 30 years ago.
>The 'excessive oil pressure' thing we can safely discount. You're not
>doing well here.
Yes, with solid lifters.
>Apply Occam's Razor. The bike has been sitting for nearly four months.
Can you actually read? It sat for a month, if that. But "I'm not doing
well", eh?
>It's reasonable to assume it was running before "it was put away", or
>the OP would have said "it hasn't run since x", but it's not a given, I
>grant you. Still, if it has been sitting for *longer* that only makes
>the stale fuel likelihood even more likely.
One month or less. Like I said, *read* the original post.
>> As am I. Sarcasm work best if you know what you're talking about.
>
>And you don't. Now, apologies for being curt, but there are times and
>places when...
You don't pick your spots too well.
Bill Vanek
<kevyN...@netins.net> wrote:
>In my 30 years working on cars NEVER has a deposit on a valve stem held a
>valve open.
So what? I have seen it.
> carbon on the valve face yes, stem Not a chance. KB
"Not a chance"? I don't know where you worked, but I worked in
dealerships (GM), and dealer mechanics see a lot of strange things
that get worked out before the cars start hitting the independents. GM
had this issue with one of their SUV's around 2005. I don't remember
which engine because it was a "foreign" vehicle - Chevy or GMC in a
Cadillac dealer. We took it in as a favor to the owner, called the
factory on a no-start problem, and that was the cause. Something to do
with tight clearances, and gasoline additives.
Bill Vanek
Older Gentleman) wrote:
>Bill Vanek <bilv...@invalid.com> wrote:
>
>> That explains what is essentially no compression in one cylinder? That
>> is an issue that needs to be addressed, don't you think? BTW, if you
>> had actually read the initial post, he said the bike sat for about a
>> month - that's all. Stale fuel? That's an interesting theory.
>
>It seems to be the case. nine times out of ten, when somebody has left a
>carb-fed[1] bike sitting for months without using it.
Once again, one month or less is not "months".
>> >Look, get SWK to strip down the carbs properly. Best solution is
>> >ultrasonic cleaning, but proper professional-style cleaning plus
>> >cleaning out all the jets with tiny strands of copper wire and lots of
>> >compressed air will, if you're patient, do the job.
>>
>> Right, that should get the compression back up.
>
>The compression isn't the issue here. It really, really isn't.
It is *an* issue. Or do you just shrug that sort of thing off? I mean,
what's a couple of dead cylinders, right? There's two more after all.
>> As they say, when the only tool you have is a hammer, every problem
>> looks like a nail. I guess when you have some special carb cleaning
>> aptitude, that's where the diagnosis always leads.
>
>I don't. But I've got a bit more experience with bikes than you have.
I'm sure you do, but probably not with engines & driveability problems
in general.
Bill Vanek
<steven...@hotmail.com> wrote:
>On Apr 8, 8:03 am, Bill Vanek <bilva...@invalid.com> wrote:
>> On Fri, 8 Apr 2011 07:18:45 +0100, totallydeadmail...@yahoo.co.uk (The
>>
>> Older Gentleman) wrote:
>> >One cylinder does look rather low, and one looks worryingly low, but it
>> >should start anyway.
>> >Your problem is stale fuel in the carbs; jellied fuel that's blocking
>> >key passageways and jets.
>>
>> That explains what is essentially no compression in one cylinder? That
>> is an issue that needs to be addressed, don't you think? BTW, if you
>> had actually read the initial post, he said the bike sat for about a
>> month - that's all. Stale fuel? That's an interesting theory.
>
>Yep the compression is a worry BUT it wont keep it from starting.
>Stale fuel? Interesting theory? Sir you are either sarcastic or a
>blithering idiot...frankly from what you've posted so far I'm inclined
>to believe the latter and call bullshit if you claim the former.
The bike sat for a month. Do any of you actually read the posts your
replying to? Or do you just fire up the mindless sarcasm when you
think you see an opening?
>> >Look, get SWK to strip down the carbs properly. Best solution is
>> >ultrasonic cleaning, but proper professional-style cleaning plus
>> >cleaning out all the jets with tiny strands of copper wire and lots of
>> >compressed air will, if you're patient, do the job.
>>
>> Right, that should get the compression back up.
>
>The compression means fuck all if it isn't running.
Right. Fuck the dead cylinders.
>> As they say, when the only tool you have is a hammer, every problem
>> looks like a nail. I guess when you have some special carb cleaning
>> aptitude, that's where the diagnosis always leads.
>
>And you madam are a TOOL.
Gee, that hurts.
Bill Vanek
not going to start. It's more effective to replace than clean.
`
> Also, with four carb bowls, if they've just been installed after
> cleaning, it can take ten or more start attempts just to get the bowls
> filled with fuel.
Well, Rabbit's Ninja does have a PRIME position on the fuel tap, so it
should be no problem to fill the float bowls.
What I see as the biggest problem here is Neil Murray (TOG) trying to
shit all over the thread (as usual), and if Rabbit doesn't know that
Neil Murray is an asshole he will be confused by his spurious
"adviceis"
M.Badger
> Hi.
>
<snip lots>
Before you do any tear down, take the air filter out and try the compression
test again -after- making damn sure all the slides are rising under finger
pressure, hence taking the air filter out, you may be able to get your
finger in to raise the slide.
If you cant get in to raise the slide manually, take the carbs off. If it is
something as simple as a sticky slide, the compression pressures will rise.
If it isn't, well, they were coming off anyway weren't they, so no biggie.
Won't take long to do.
The Older Gentleman
> Can you actually read? It sat for a month, if that. But "I'm not doing
> well", eh?
>
> >It's reasonable to assume it was running before "it was put away", or
> >the OP would have said "it hasn't run since x", but it's not a given, I
> >grant you. Still, if it has been sitting for *longer* that only makes
> >the stale fuel likelihood even more likely.
>
> One month or less. Like I said, *read* the original post.
I did. The mniddle of winter makes it worse. It's now sat for four
months.
The Older Gentleman
> It does occasionally die once warmed up or kinda bog down and
> won't go past about 4kRPM ish.
It's the carbs.
The Older Gentleman
This is Krusty. Accuracy is optional.
The Older Gentleman
> Right. Fuck the dead cylinders.
It doesn't have two dead cylinders.
The Older Gentleman
> >The compression isn't the issue here. It really, really isn't.
>
> It is *an* issue. Or do you just shrug that sort of thing off? I mean,
> what's a couple of dead cylinders, right? There's two more after all.
It doesn't have two dead cylinders.
Want a JCB for that hole you're digging?
The Older Gentleman
And that qualifies you to speak about engines incredibly more
sophisticated and with massively higher specific power outputs? With the
best will in the world, I've heard loads of people pontificate "because
they know about cars".
Loads of people have told me that the bike I'm thinking of buying, and
which I can see has been bodged, has been serviced by their dad who
"knows all about motors"[1].
Even if it does, the point is one of simple probability. You can
half-remember *one* vehicle which had some sort of issue in the last
decade.
This ng gets loads of people complaining that their bikes don''t start
after (usually winter) lay-offs. And I can't remember one that *wasn't*
fuel related, though there may have been one.
Now, winter can bollox carbs in a surprisingly short time. I left one of
my bikes parked outside in January 2010. I'd been using it as a daily
commuter, and it ran perfectly, every day. Went on holiday. Came back.
Would it start? Would it buggery. It had sat in two weeks of the
nastiest winter we've had here for many years. I tried everything.
Heating the plug, new plug, fresh fuel, you name it. Got it going in the
end and it ran as rough as feck. I ended up stripping down the carb and
cleaning it and rebuilding it *properly*, and all was well.
What had happened to the carb while it had been standing for a mere
fortnight? No idea. I'd guess at something condensing in the carb and
then freezing, but really, I've no idea. All I knew was that the problem
wasn't going to be the head gasket )although there's a tiny weep from
it) nor the compression, nor the ignition, nor anything *except* the
carb.
And here's you asking him to check the oil, check the type of oil,
suggesting checking hydraulic lifters, saying that it has two dead
cylinders when it doesn't, suggesting the valve stems may be carboned up
and stopping the valve from closing, suggesting plugs may be carbon
tracked (when did that last happen on any Jap bike other than a
two-stroke??), and all kinds of similar, highly unlikely, things when
the most likely problem area is...
... the carbs.
Could be a duff fuel tap as well, but that's so easy to check.
Incidentally, let's move onto the compression issue. The OP now says it
"ran fine the last time it was out". On ukrm a while back we had a bod
who had such incredibly low compression on *all four* of his cylinders
that I (and others) told him that the dealer couldn't have been checking
correctly. I can't remember what the readings were, but they were way,
*way* lower than the lowest reading on the one possibly-problematic pot
that this engine has.
I mean, you don't get compression failure on *all* cylinder
simultaneously unless something catastrophic has happened.
And then he admitted, shame-faced, that he'd accidentally run the thing
on diesel. OK, that'd do it.
Decades ago, I neglected the shims on a GS Suzuki (I was skint and just
couldn't afford to pay a dealer and didn't then have the nous to DIY).
Turned out it had compression that was damn near atmospheric, but it
still ran. One cylinder with a tested compression of 30-48psi, even
assuming that figure is accurate (I've nothing to say it isn't)....
Is
Not
Going
To
Be
An
Issue
Here.
[1] Or, almost as often, who "knows all about bikes" because he had a
BSA in 1960.
Rabbit
Some more details:
1) When I said it would occasionally plutter, smoke and then run fine
the smoke was black, not too thick and didn't hang around for a while.
It is generally after riding for more 5 minutes, during which it runs
fine. This is only happens occassionally but I can't see to see any
major patter, just generally within 5-20mins after starting.
2) I have tried starting it on a closed trottle.
3) When cleaning out the carbs I made sure of cleaning out all the
starter jets and passeways.
4) When I said it ran fine the last time it was out it did indeed run
fine. The last time I took it out was to a garage to check out the
shock. It ran fine there, the mechanic said it ran well when he took
it for a test drive the next day, and it ran well the following day on
my journey back home. Then, due to snow, it put away until January.
5) The carb slides all moved smoothly when I reinstalled them but will
check when the airbox is off again.
6) The fuel tap is fine, have tested.
7) I have had the bike tuned on a dyno before and it is these settings
that I returned the carbs to (double checked on disassembly), not what
is in the manual.
8) I filled the float bowls by putting tank on prime and opened the
screws at the bottom of the float bowls.
9) I have replaced the spark plugs.
I will try the following:
a) Fully unscrew the idle adjuster and try to start.
b) As above but with full choke applied.
c) I'll take out the airbox and hand choke the carbs.
d) Investigate air leak at rubbers - unscrew idle screws out further.
Should start but will get poor idle when warm
e) Reduce spark gap and try again.
I'll let you know how I get on.
`
> Cheers for all the excellent posts.
Are you in the UK, or Canada?
> 1) When I said it would occasionally plutter, smoke and then run fine
> the smoke was black, not too thick and didn't hang around for a while.
> It is generally after riding for more 5 minutes, during which it runs
> fine. This is only happens occassionally but I can't see to see any
> major patter, just generally within 5-20mins after starting.
Two possible causes would be (1) the float valve doesn't always seal
properly due to gum and varnish or debris coming down from the gas
tank, and (2) some mechanic has improperly adjusted the idle mixture
screws.
The latter is a very common error amongst shade tree mechanics. They
expect that the idle RPM will increase as they turn the idle mixture
screw more and more counterclockwise.
After about 3 full turns, the idle screw has *NO* further effect to
raise the idle RPM, it has the *opposite effect*, the idle RPM
decreases because the mixture becomes *too rich* and the engine
stalls.
The newbie mechanic then tries to adjust the idle speed screw and this
casues the throttle butterflies to uncover a pattern of three
acceleration transition ports that aren't supposed to be uncovered at
idle.
When the newbie blips the throttle to check for correct throttle
response, the engine gets extra gas through the transition ports and
the idle RPM hangs up at 4,000~5,000 RPM and may take 30 seconds to
fall back down to the specified idle RPM.
A motorcycle with a rich condition like that cannot be ridden safely,
the engine keeps driving it into corners and up to stop signs.
When the engine gets warm, the idle RPM will rise up and hang there,
and the newbie mechanic guesses that maybe there's something wrong
with his throttle cable.
The newbie mechanic may be smart enough to turn the idle speed knob
back down, but by that time he's lost track of what he did wrong,
which was when he opened the idle mixture screws too far.
I can usually find the factory idle screw setting from looking at
parts lists, but it's not in the online parts diagram for the 1986
Ninja 600 at www.powersportspro.com.
Nor does the parts list tell me what size the pilot jet is.
But a typical pilot jet for an engine that size would be around #30
and I would start with the idle screws set around 1.0~1.25 turns out
from lightly seated and check for throttle response upon blipping the
throttle and I would observe whether the RPM hung up when the engine
warmed up.
> d) Investigate air leak at rubbers - unscrew idle screws out further.
> Should start but will get poor idle when warm
The engine should start on full choke, no throttle, regardless of what
the idle screw settings are because the cold enricher system
*bypasses* the idle mixture system.
If the engine starts on the choke with the idle speed screw turned out
the way out, you'll have to hold the throttle open to get it to run as
you re-adjust the idle speed upward.
Then, when the engine is warm, adjust the idle mixture screws if the
engine won't idle or if the idle speed hangs up upon blipping the
throttle or when the engine gets hot.
As I explained above, you don't want to open the idle mixture screws
too far.
The normal procedure is to turn the idle mixture screws *IN*, not out,
and adjust the idle speed *DOWN* not up.
16014 16014-1029 SCREW,PILOT ADJUST | CN
16014A 16014-1054 SCREW-PILOT AIR | CA,US
92063A 92063-1008 MAIN JET,#100 | CN,US
92063B 92063-1009 MAIN JET,#105 | CN,US
92063C 92063-1009 MAIN JET,#105 | CA
92063D 92063-1115 JET-MAIN,#102 | (RACING USE ONLY)
92063E 92063-1116 JET-MAIN #108 | CN,US
92063E 92063-1116 JET-MAIN #108 | CN,US
92063F 92063-1117 JET-MAIN #112 | CN,US
92063F 92063-1117 JET-MAIN #112 | CN,US
92064 92064-1119 JET-PILOT
paul c
That all makes sense to me, at least for an engine that has no other
problems. Just want to mention that I suggested turning out the idle
mixture screws solely to see if that would help the engine start in
which case a manifold boot air leak would be easier to notice. I should
have mentioned I meant that as only a temporary measure. As you say,
it's not pleasant to ride with an engine that's set too rich.
paul c
> paul c<anon...@not-for-mail.invalid> wrote:
>
>> On 08/04/2011 4:56 PM, ` wrote:
>> ...
>>>> 5) They are CV carbs.
>>>
>>> One of the problems that confuses newbies is that CV carburetors don't
>>> have a real plate type choke. They have cold starting enricher valves
>>> which are opened when the "choke" lever or knob is moved to the ON
>>> position.
>>> ...
>>
>> Minor point - at least a few CV carbs do have a 'plate' choke, eg., the
>> ones on the 1982 DOHC CB750's.
>
> This is Krusty. Accuracy is optional.
>
>
I find his technical advice to be routinely pertinent. Over the last
five or six years it's been pretty obvious to me that he is the resident
expert on carbureted fuel problems. There have been a few other
regulars, such as Mark O and Rob K who also give sensible advice on a
variety of mechanical/electrical topics. I mean actionable advice,
without a lot of hand-waving or editorializing.
Keith
IGNORE this idiot...he's so stupid he couldn't pour piss out of a boot
with the directions printed on the bottom in large block letters.
Keith
They aren't dead you dipwad...you are starting to sound as smart as
Krusty.
> >> As they say, when the only tool you have is a hammer, every problem
> >> looks like a nail. I guess when you have some special carb cleaning
> >> aptitude, that's where the diagnosis always leads.
>
> >And you madam are a TOOL.
>
> Gee, that hurts.
It should...
Keith
Gentleman) wrote:
> Bill Vanek <bilva...@invalid.com> wrote:
> > Right. Fuck the dead cylinders.
>
> It doesn't have two dead cylinders.
You know that, I know that but the GM mechanic doesn't think so...then
again the worst mechanics I've EVER met worked in dealerships. Most
were incompetant at best.
Keith
Gentleman) wrote:
> Keith <stevenkei...@hotmail.com> wrote:
> > Oh shut the fuck up you idiot...
>
> Cruel but succinct and accurate.
>
TYVM...I do my best.
Keith
> On Apr 8, 2:02 pm, The Little Okie Retard <stevenkei...@hotmail.com>
> wrote:
>
> > Oh shut the fuck up you idiot...
>
Uh, news flash chid molester...he's taller than you. You are taller
than me...but I can kill you with one hand behind my back and not even
feel a twitch of emotion or give a shit. Now do fuck off you piece of
shit.
Keith
> On 09/04/2011 1:28 AM, The Older Gentleman wrote:
>
>
>
>
>
>
> - Show quoted text -
BULL SHIT...he just cuts and pastes without attribution from other web
pages. But he, go ahead, keep thinking he's smart...but that just
makes you even dumber than he is.
Keith
No, not it isn't hard to get them full to the proper level and it sure
doesn't take 10 attempts to start to do that. But hey, you obviously
went to krusty's ass sucking school of motorcycle exspurtease.
The Older Gentleman
> Over the last
> five or six years it's been pretty obvious to me that he is the resident
> expert on carbureted fuel problems.
He can copy & paste. He has no practical experience, and he's also the
bod who advised a poster to rip out his ignition system when it was
patently obvious it was the carbs that were at fault.
As the poster admitted later, when he fixed them.
`
Shit know as Neil Murray) wrote:
> He can copy & paste. He has no practical experience, and he's also the
> bod who advised a poster to rip out his ignition system when it was
> patently obvious it was the carbs that were at fault.
You're a lying sack of shit. It was your sock puppet's own idea to
remove his coils for testing.
The Older Gentleman
Indeed, and as we've proved before by pointing people to the relevant
postings, you encouraged him to do it.
Next!
--
BMW K1100LT Ducati 750SS Kawasaki GPz750 Honda CB400F
Triumph Street Triple Suzuki TS250ERx2 GN250.
Keith
and you once again avoid admiting encouraging said actions much less
your own misguided and bad advice on the entire matter. Admit it...you
know nothing about anything that matters. Motorcycles, beer and pussy
being the only things in the world that matters. Being a nonriding,
perscription drug abusing pedarastic zoophile that makes it rather
obivous that your advice is best only observed for it's "What not to
do" factor.
Keith
Gentleman) wrote:
> ` <breoganmacbr...@yahoo.com> wrote:
> > On Apr 10, 8:01 am, totallydeadmail...@yahoo.co.uk (The Lying Sack of
> > Shit know as Neil Murray) wrote:
>
> > > He can copy & paste. He has no practical experience, and he's also the
> > > bod who advised a poster to rip out his ignition system when it was
> > > patently obvious it was the carbs that were at fault.
>
> > You're a lying sack of shit. It was your sock puppet's own idea to
> > remove his coils for testing.
>
> Indeed, and as we've proved before by pointing people to the relevant
> postings, you encouraged him to do it.
>
> Next!
Fine. The smoke came of of the coils of my ariel atom*...should I
clean the carb and relube the wheel bearings and see if that will help
it start?
*Note, I wouldn't mind owning an Arie Atom if for no other reason than
I could trade it for old suzuki parts.
walt tonne
motorcycle
production. Squirt a shot of that gummy red stuff into the plug
openings, crank
motor for a couple of minutes, take off.
TOG@Toil
Yeah, *right*. Up there with Instant Rebore (which was applied in the
same way) as one of the great Snake Oil rip-offs.
Keith
heh true that...but to be fair the "Italian tuneup@" using seafoam
does/can work unless the carbs are well and truely buggered or the
rings shot. 8^) It might be snake oil but it does work and if you have
to lay up a motorcycle for some reason it works better than Sta-bil
ime. YMMV IANAL
But if one more idiot tries to sell me on deer whistles I'm going have
their scrotum for a dice bag and their shin bone for a pencil box.
Gus
<stevenkei...@hotmail.com> wrote:
> But if one more idiot tries to sell me on deer whistles I'm going have
> their scrotum for a dice bag
How you gonna convince TOG to let you suck his balls again after a
threat like that?
Keith
<YAWN> oh lookie ol Krusty the kiddie molester morphed again.