Help - JR50 engine bogs
Joe Blow
In article <33554F...@novell.com>
Benjamin Cristi <benjami...@novell.com> wrote:
>
> I've got the service manual on order. In the meantime, can someone
> advise what to try? It's a 1978.
>
> SYMPTOMS:
> -It bogs down when the throttle is opened around mid rpm or higher, and
> under a load. low rpm's are fine.
> -It revs freely under no load when warm (in neutral)
> -If I free-rev (scream) it, it seems to 'clean out' and run better for a
> while.
> -It doesn't bog as bad if the choke is partially opened.
>
> What I've checked/tried so far:
> -New spark plug, checked points and gap.
> -Checked top end, it's ok.
> -decarbonized exhaust port, and as much of the exhause pipe as I could.
> -checked carb for dirt & deposits, checked float level
> -checked for restrictions in fuel line and filter.
> -cleaned air filter.
u may need new points and a condenser. or maybe your bike is jetted wrong
for your area.
Benjamin Cristi
Benjamin Cristi
Please reply to the list for now. My email is acting up.
MX Tuner
>SYMPTOMS:
>-It bogs down when the throttle is opened around mid rpm or higher, and
>under a load. low rpm's are fine.
>-It revs freely under no load when warm (in neutral)
>-If I free-rev (scream) it, it seems to 'clean out' and run better for a
>while.
>-It doesn't bog as bad if the choke is partially opened.
Have you cleaned the silencer. If it clogs up, you may experience
these symptoms.
Oh, and it doesn't have points or condensor.
MX Tuner
Benjamin Cristi
I forgot to mention, I did pull off the non-stock spark
arrestor/muffler, and the bogging problem diminished somewhat. The pipe
end is also fairly restrictive.
How do you decarbonize a pipe?
Also, it does have points. I pulled the left side cover off, you can see
the points through slots in the magneto/flywheel? Remember, it's a '78.
Thanks for the advice,
Ben
Joe Blow
In article <5j3np3$h...@camel7.mindspring.com>
mxt...@atl.mindspring.com (MX Tuner) wrote:
>
>>SYMPTOMS:
>>-It bogs down when the throttle is opened around mid rpm or higher, and
>>under a load. low rpm's are fine.
>>-It revs freely under no load when warm (in neutral)
>>-If I free-rev (scream) it, it seems to 'clean out' and run better for a
>>while.
>>-It doesn't bog as bad if the choke is partially opened.
>
> Have you cleaned the silencer. If it clogs up, you may experience
> these symptoms.
>
> Oh, and it doesn't have points or condensor.
>
> MX Tuner
if it doesnt, then what kind of ignition it got? im positive it aint
digital and i know of no other ignitions on dirt bikes.
MX Tuner
>I forgot to mention, I did pull off the non-stock spark
>arrestor/muffler, and the bogging problem diminished somewhat. The pipe
>end is also fairly restrictive.
>How do you decarbonize a pipe?
The only way I know of besides a chemical dip is to heat it with a
torch. The carbon will burn out. Oh, and it makes a BIG stinkin'
smokin' mess!
MX Tuner
TMaxel
In article <33563F...@novell.com>, Benjamin Cristi
<benjami...@novell.com> writes:
>How do you decarbonize a pipe?
>
>
Ben, I didn't offer any advice because I am not too familure with the
JR50... But, now you have asked a question I am familure with. :-)
My PW 50 pipe would fill up pretty quick. About once a month I would
build a little bon fire in the back yard and put the pipe in the fire.
Now
you have to be very, very careful (If your not an adult, please ask some
one else to do this for you) there will be flames that will shoot out the
ends of the pipe and you can not leave it lay too long or the pipe will
get soft and warp (deform).
Move it around, take it out once and a while and let it cool a little bit
and
once the flames stop coming out the ends your ready to take it out. At
this point you have the oil and fuels burnt up and everything should be
good and hot inside. Let the pipe cool just enough that it won't bend
on you (about 5 to 10 min) and start tapping the pipe and let the carbon
fall out. Once this is all done, hit the pipe with a wire brush, spray it
with some grille paint and its good as new!
As for the silencer, you can do the same thing and repack it with new
packing (if its packable, I'm not sure).
If you blow oil right away (out the end of the pipe) I would look into
leaning out the injector pump a little bit. I know on the PWs, the pump
is setup that with time it will richen itself and you have to adjust it
back
to the stock setting which will lean it out a tad.
Good luck, hope this helps you. :-)
TMaxel
Alright Jeremy! Go TEAM Nac Nac!
McGrath, Albertyn, Heemsbergen and Maxel... What a team! Go Zuki!
EMail -> MAXEL%MTC...@Navistar.com
RM 250, #53, Me
RM 80, #44, Tommy
KX 60, #44, Tommy & Tyler
LEM CR3, #35, Tyler
SSmyers102
>If you blow oil right away (out the end of the pipe) I would look into
>leaning out the injector pump a little bit. I know on the PWs, the >pump
>is setup that with time it will richen itself and you have to adjust it
>back
>to the stock setting which will lean it out a tad.
Just to make sure no one misinterprets this-and I agree with Ben- If
the oil pump increases the volume of oil in the fuel/oil mixture, the
fuel/air mixture has been leaned-- reducing the amount of oil will richen
the fue/l air mixture.
I think Benjamin knows what he is trying to say, "leaning " the pump
menas it will flow less oil , but some might think the actual fuel/air
mixture was what was being leaned, and it is actually the reverse.
Benjamin may have also touched on what is wrong with the bike- if the
symptoms seem to be that it is running real lean- maybe it is getting too
much oil- If it seems to be too rich it may not be getting enough- but I
don't think you can judge the mixture by the spooge coming out of the
pipe- as lots of spooge probably means that it is getting too much oil and
it is actually lean- confusing. eh ? So I would attempt to set the
injector back to stock settings and then look at the pump output- most of
these pumps can be tested by measuring the output (service manual should
cover this) and then get the carb in the ballpark- if the pump adjustment
drifts as Ben pointed out the previous owner may have adjusted the carb to
compensate and now it is all out of whack.
BTW, spooge(TM) courtesy of Tom Webb, who probably lifted it from
Super Hunky ( great name for a candy bar btw)
Scott Smyers- anxiously awaiting the return of his KTM from the doctor,
where a saddle height reduction is in progress
Neil Wig
In article <19970418141...@ladder01.news.aol.com>, tma...@aol.com
(TMaxel) wrote:
> In article <33563F...@novell.com>, Benjamin Cristi
> <benjami...@novell.com> writes:
>
> >How do you decarbonize a pipe?
> >
> >
>
> Ben, I didn't offer any advice because I am not too familure with the
> JR50... But, now you have asked a question I am familure with. :-)
>
> My PW 50 pipe would fill up pretty quick. About once a month I would
> build a little bon fire in the back yard and put the pipe in the fire.
> Now
Would it work to take it to an engine shop and have them toss it into the
hot tank overnight? I used to run VW bugs (Full modified, cammed to the
nuts.....) and we used hot tanking to remove paint from the engine tin
(cooling shrouds) before the custom paint went on. The tin came out shiny
clean. I assume this would also work for the pipe, with a lot less risk
than burning it out. The last batch of engine tin cost me $15 so I would
expect a pipe would cost about $10.
--
Neil Wig
"There may be a Heaven, and there may be a Hell. I'll take the sure thing and take my Heaven now" Pat Wicker 1988.
TMaxel
In article <19970418172...@ladder01.news.aol.com>,
ssmye...@aol.com (SSmyers102) writes:
> I think Benjamin knows what he is trying to say, "leaning " the pump
>menas it will flow less oil , but some might think the actual fuel/air
>mixture was what was being leaned, and it is actually the reverse.
>
>
Actually, I, was talking about leaning the pump... Your right, I was not
real clear on that. By the way... Why do you call me Ben? :-)
(I don't know why, but I was the one that replied, Ben's name was
pasted when you replied) :-)
RacerX
We perhaps own the worlds fastest JR-50 having raced them when my son
started. You know that the first Loretta Lynn 50cc championship was
won by a JR50. I know you have looked but I'm willing to bet one of
the passages in your carb is blocked. It doesn't take much and all
that stuff about the pipe, it has a small screen in it and even the
worst I ever saw wasn't even 1/4 restricted (we had to cut them up to
make modified pipes back then)....Chem boil the carb. Heck if you live
in Texas I'll give you a stock carb to try.
Dan Galvin
In article <335c203...@news.flash.net> RacerX, Rac...@race.track
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If you want to do the pipe I have my sand blasted when I have the frame
done I am not sure about the passages in the pipe itself and the removal
of sand from these passages though.
On another note does anyone know if there are decal kits and seat kits
available like the ones available for the PW 50. Thanks