Fuelish questions - Pinging '96 KTM 360 EXC
n...@bnc106nbl.bently.com
I just got a '96 KTM 360 exc and it seems to ping badly under moderate
loads at rpm's between 2000-3500. I use Chevron super unleaded with
maxima oil at 40:1.
Do I need to use race gas?
What about avgas?
What about octane boosters? which ones are good, if any?
a challenge: explain the octane rating system coherently.
thanks for your help,
nate littrell (N8)
-------------------==== Posted via Deja News ====-----------------------
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Mark Klein
>I just got a '96 KTM 360 exc and it seems to ping badly under moderate
>loads at rpm's between 2000-3500. I use Chevron super unleaded with
>maxima oil at 40:1.
Check to see which head you have. You probably have the early
production head. I don't know the markings, but I know who
does.....CARIBOU, where are you?
> Do I need to use race gas?
Wouldn't hurt.
> What about avgas?
Definitely not.
> a challenge: explain the octane rating system coherently.
Piece of cake. Octane is the rating system used to describe the
anti-knock capability of fuel.
Now the tough part (for me, anyway).
There are two (common) methods of figuring octane. The "research"
method and the "motor" method. From what I understand, the research
method is more of what a fuel is designed to do whereas the motor
method is an actual measurement of what it can do. I know this is not
100% correct, but is something along these lines.
So when you see the R+M/2 label on gas pumps, that means it is an
average of the two methods. When you compare fuels and their octane,
be sure they are measured using the same system. One can be something
like 10 points higher when not averaged with the other. Can be
misleading.
MX Tuner
Simmonsmc
Try raising the needle a notch,you might be a little lean in the mid
Mike Simmons
Simmonsmc
Mark why do you say not to use avgas?, I used it in my husky for well over
a year
with great results it is always the same and is 110 octaine,my owners
manual rec
ommands 98+ ! I Only stoped using it when I discovered it would run fine
on pump gas,with alittle octane booster, avgas is only about 2.00 a gallon
vs. 5.00 for race
Just curious to know your opinion, my bike is a 93 and still on the
origional piston
I checked it a month ago it still had about .002 clerance. I think it is
from the oil I have always used DUMONDE TECH DTP have you ever heard of
it? you should look into it, it works great!!
Mike Simmons
Bruce Arnold
Caribou1 <cari...@ptd.net> wrote in article <33009B...@ptd.net>...
(snip...)
> I've never tried octane boosters in a bike (does anyone else have
> feedback on that?), but I did run it in my old '69 Judge (Ram Air IV).
> --
> Caribou 93 Ariens ST-8 Blower "Frosty"
I used to have a 1982 XR-250R that pinged in very low-RPM/high-load
situations, especially if it was too hot (which it almost always was). I
used STP octane booster at about twice the recommended ratio, and it worked
great, and never caused any problems that I am aware of. Of course, XRs
are not nearly as highly tuned as a modern 2-stroke, so I have no idea if
it could cause any negative consequences in a race bike. Still, it seems
like the best solution would be to correct the problem, rather than hiding
it with additives. My old XR probably just needed some minor jetting work
(and a lighter rider).
Bruce
Kerry Simmons
There was a service bulletin a couple years back from Kawasaki saying
NOT to use octane boosters. It was under a large WARNING header and
said that octane boosters can cause serious damage. When I inquired
further, I was told octane boosters can eat away at rubber and nylon (ie
carb needle & seat; crank seals).
I had used octane boosters years prior to reading this with no problem
whatsoever (although I never had a bike more than 2 years), but decided
it wasn't worth the risk. So I went to race gas. Bike runs a lot
better with race gas anyways, so it's well worth it!
Kerry
MotoPlex2
http://www.impactracing.com
Mark Klein
>I used to have a 1982 XR-250R that pinged in very low-RPM/high-load
>situations, especially if it was too hot (which it almost always was). I
>used STP octane booster at about twice the recommended ratio, and it worked
>great, and never caused any problems that I am aware of. Of course, XRs
>are not nearly as highly tuned as a modern 2-stroke, so I have no idea if
>it could cause any negative consequences in a race bike. Still, it seems
>like the best solution would be to correct the problem, rather than hiding
>it with additives. My old XR probably just needed some minor jetting work
>(and a lighter rider).
When you're dealing with detonation, there are a few things which can
cause it. One or any combination of these can create "pinging". High
compression, timing advance, and fuel/air mixture being too lean among
other things. Most of todays two strokes have low enough compression
ratios to the point that is not one of the causes. Also, as stated
earlier in this thread, squish band can aggrivate a detonation problem
(i.e. YZ490's, KTM360's, etc.).
4 strokes, on the other hand, rely on higher compression to get some
horsepower out of 'em.
MX Tuner
Cam Mitchell
Classic KTM syndrome.. don't worry, in a week you will have other bigger
problems that will take your mind off of the pinging.
--
/-------------------------------------\
| bcm...@bikerider.com |
>-------------------------------------<
| http://users.uniserve.com/~cmitchel |
\-------------------------------------/
High Lord Gomer
Caribou1 <cari...@ptd.net> wrote:
>I agree. As I understand it, octane stabilizes the rate of flame
>propagation and reduces the propensity of the mixture to detonate from
>compression. The more consistent the rate of flame propagation, the
>greater the timing advance you can run (within limits of course) and the
>more effeciently you can burn the fuel. For many years they used lead
>compounds which worked great except for the side effects (re: Gomer ;)).
Oh yeah, like *nobody* else has a few extra appendages!
> I've never tried octane boosters in a bike (does anyone else have
>feedback on that?), but I did run it in my old '69 Judge (Ram Air IV).
>If its the same stuff, do NOT get it on your skin. It gets absorbed and
>causes cyanosis, which causes your blood to stop absorbing oxygen, and
>can make you pass out. Come to think of it - everything looked orange.
Apparently doesn't wear off, either.
Gomer
95 YZ250 (Old Man)
95 XR100 (Young kid)
96 50SXR (Younger kid)
Jeff @ MX SOUTH
I agree with everything that I have read in this thread including the
warning about AV-gas.
If you decide to go with race fuel I have a very good race fuel for
you to try. It is made by Klotz and is a concentrate. Don't be
confused now, it is not a booster it is a race fuel concentrate. You
mix it with pump fuel and you will get a very good and stable race
fuel that is 10 octane points higher than the pump fuel you chose.
I can ship this concentrate right to your door. It comes in either 1
gallon or 5 gallon cans. A 1 gallon can of concentrate will make 10
gallons of race fuel and a 5 gallon can will give you 50 gallons of
fuel. The final cost of your race fuel will end up costing around $3
a gallon depending on the price of the pump gas you buy. Wich is
usually very good as far a race gas goes.
Jeff
n...@bnc106nbl.bently.com wrote:
>I just got a '96 KTM 360 exc and it seems to ping badly under moderate
>loads at rpm's between 2000-3500. I use Chevron super unleaded with
>maxima oil at 40:1.
> Do I need to use race gas?
> What about avgas?
> What about octane boosters? which ones are good, if any?
> a challenge: explain the octane rating system coherently.
>thanks for your help,
>nate littrell (N8)
>-------------------==== Posted via Deja News ====-----------------------
> http://www.dejanews.com/ Search, Read, Post to Usenet
Jeff @ MX SOUTH
m...@pipeline.com
http://www.bews.com/mxsouth
305-255-3718
305-255-2555
Caribou1
Gosh, thats excellent advice Cam...
--
Caribou 93 Ariens ST-8 Blower "Frosty"
91 True Value Shovel "@!&*ing Snow!"
78 KTM 250 (AHRMA 626) "Katie"
95 KTM 300 MX/C "Sissy"
90 Intruder 1400 "Suzie"
Lynn 96 XR100 "Putt-Putt"
Caribou1
Mark Klein wrote:
clip..
> When you're dealing with detonation, there are a few things which can
> cause it. One or any combination of these can create "pinging". High
> compression, timing advance, and fuel/air mixture being too lean among
> other things. Most of todays two strokes have low enough compression
> ratios to the point that is not one of the causes. Also, as stated
> earlier in this thread, squish band can aggrivate a detonation problem
> (i.e. YZ490's, KTM360's, etc.).
>
> 4 strokes, on the other hand, rely on higher compression to get some
> horsepower out of 'em.
>
> MX Tuner
Don't forget carbon deposits either. They increase compression and can flouresce
causing pre-ignition.
Dennis Kennedy
This should be the '96 KTM 360 EX/C jetting faq:
Subject: Re: 97 360 ktm jetting
From: Tom Niemela <Tom_N...@ccm2.hf.intel.com>
Date: 1996/11/06
This will make the mighty 360 run like it should:
'96 Katoom 360:
*Make sure it does NOT have the cylinder head code #360-1(too much
compression)
*replace stock pipe and muffler - wrong stinger diameter on it. *45 or 48
pilot
*175 or 180 mainjet
*1467"NS" Honda needle - be SURE it says NS!
*reed spacer: KTM was trying to make more low end volume. Don't need it
if you're using the above mods.
'97 Katoom 360:
*just change jetting to above numbers
Note: both 250 and 360 needles for woods riding are too radical of fuel
delivery curve. Honda makes it more linear. The bike really does like
GOOD fuel i.e. race gas mix. Suggest approximately 1/3 race gas with
pump.
Hope that helps.
Volker Bartheld
Hi !
Caribou1 wrote:
> Mark Klein wrote:
> > >I just got a '96 KTM 360 exc and it seems to ping badly under moderate
> > >loads at rpm's between 2000-3500. [...]
> You might try a richer needle with the same clip setting.
I just fiddled around with my '94 XR600R's carb. I had similar
problems. Especially when the engine was hot (which seems to be the
usual thing for an XR600...) it tended to 'ping' when accelerating
from low RPM with half...full throttle. Changing the main jet didn't
help (spark plug looked OK - a light brownish tan), so I assumed that
the mid-range mixture was too lean. I raised the jet needle one notch
(i.E. dropped the clip one notch) and ... hey ! Worked fine. No
pinging, more torgue. The only disadvantage of that 'operation' is,
that you'll have to remove the carb every time if you want to change
the needle position. This includes removing the gas tank, seat,
and some plastic parts... Approx 1 hour of work.
> > > Do I need to use race gas?
> > Wouldn't hurt.
If paying more money for fuel than necessary doesn't hurt, I
agree. I use standard pump gas and care of my jets and air filter...
> > > What about avgas?
> > Definitely not.
Uuups. 'avgas' ? Never heard.
> [...] As I understand it, octane stabilizes the rate of flame
> propagation and reduces the propensity of the mixture to detonate from
> compression. The more consistent the rate of flame propagation, the
> greater the timing advance you can run (within limits of course) and the
> more effeciently you can burn the fuel. For many years they used lead
> compounds which worked great except for the side effects (re: Gomer ;)).
Right. But trying to cure a heavily de-jetted engine with higher octane
fuel is not the right approach to the problem as it seems to me.
> I've never tried octane boosters in a bike [...]
'Standard' 4-strokes (no special cylinder head, high compression
modifications) shouldn't need such add-ons. Save the money for
and oil-cooler (as I do for my XR at the moment)...
Bye,
Volker
mtr...@cohvco.org
This brings up a question that I have about fuel. I apologize if we discussed
this a few months ago. I run straight 108 race gas during the winter months
(Denver uses some type of oxy. fuel from November - March) and mix 108 race
gas and premium pump gas during the summer.
What's better running straight race gas or mixing something like Klotz
concentrate with pump gas? I would assume it's better not to use any of these
big city winter oxy. fuels at all if possible.
I ask the question because I can't always get out during the week to get race
gas and I've been thinking about buying some Klotz concentrate. That way I can
just pick up some pump gas to add to it when I fill up the truck on the way
out of town.
Mike Troast 97 KTM300exc
Dennis Kennedy
I've done this so many times on my KTM 360, I can do it in about 15
minutes now. It really helps to have an 8mm t-handle.
Dennis
Volker Bartheld (bart...@afmp04.mppmu.mpg.de) wrote:
: pinging, more torgue. The only disadvantage of that 'operation' is,
: that you'll have to remove the carb every time if you want to change
: the needle position. This includes removing the gas tank, seat,
: and some plastic parts... Approx 1 hour of work.
: Bye,
: Volker
Mark Klein
>I ask the question because I can't always get out during the week to get race
>gas and I've been thinking about buying some Klotz concentrate. That way I can
>just pick up some pump gas to add to it when I fill up the truck on the way
>out of town.
I like to use race gas if for no other reason than it comes out of
drums and is 100% uncontaminated and I know it is the same every time
I get some.
MX Tuner
Jeff @ MX SOUTH
mtr...@cohvco.org wrote:
>This brings up a question that I have about fuel. I apologize if we discussed
>this a few months ago. I run straight 108 race gas during the winter months
>(Denver uses some type of oxy. fuel from November - March) and mix 108 race
>gas and premium pump gas during the summer.
>What's better running straight race gas or mixing something like Klotz
>concentrate with pump gas? I would assume it's better not to use any of these
>big city winter oxy. fuels at all if possible.
>I ask the question because I can't always get out during the week to get race
>gas and I've been thinking about buying some Klotz concentrate. That way I can
>just pick up some pump gas to add to it when I fill up the truck on the way
>out of town.
>Mike Troast 97 KTM300exc
Mike,
The Klotz concentrate will stabilize the pump gas that you use, so you
should'nt have a problem with whichever pump gas you use.
If you don' t already have a source for the concentrate I would be
happy to ship it right to your front door.
Happy octane,
Jeff
Charles Etris
>I just got a '96 KTM 360 exc and it seems to ping badly under moderate
>maxima oil at 40:1.
The one thing that helped my MXC the most was having the early head
modified for lower compression. The early heads were stamped at the
factory with <3601>. I removed my head (the bike's actually), sent it
back to KTM through my dealer, and in about a week I had it back. They
modified it at no charge and stamped a <5> next to the <3601> using a
hand stamp so you can tell that it has been modified.
I still get some small amount of pinging at very low RPM under heavy
loads running premium pump gas. I suppose there is some performance
loss with this mod but the only thing I really noticed was a slightly
smoother mid-range hit compared to the original head. I have not tried
milling the .4mm off the head, I think I saw this mod in one of the mags
and they claimed it helped some.
Chuck
Dennis Kennedy
Caribou1 (cari...@ptd.net) wrote:
: Cam Mitchell wrote:
: >
: > Classic KTM syndrome.. don't worry, in a week you will have other bigger
: > problems that will take your mind off of the pinging.
: >
: > --
: > /-------------------------------------\
: > | bcm...@bikerider.com |
: > >-------------------------------------<
: > | http://users.uniserve.com/~cmitchel |
: > \-------------------------------------/
: Gosh, thats excellent advice Cam...
: --
: Caribou 93 Ariens ST-8 Blower "Frosty"
: 91 True Value Shovel "@!&*ing Snow!"
: 78 KTM 250 (AHRMA 626) "Katie"
: 95 KTM 300 MX/C "Sissy"
: 90 Intruder 1400 "Suzie"
: Lynn 96 XR100 "Putt-Putt"
What would you expect from someone who has owned as many dirt bikes (let
alone KTMs) as Cam has. ;)
Dennis
gra...@aol.com
>This brings up a question that I have about fuel. I apologize if we discussed
>
>this a few months ago. I run straight 108 race gas during the winter months
>(Denver uses some type of oxy. fuel from November - March) and mix 108 race
>gas and premium pump gas during the summer.
>What's better running straight race gas or mixing something like Klotz
>concentrate with pump gas? I would assume it's better not to use any of these
>
>big city winter oxy. fuels at all if possible.
>I ask the question because I can't always get out during the week to get race
>
>gas and I've been thinking about buying some Klotz concentrate. That way I
>can
>just pick up some pump gas to add to it when I fill up the truck on the way
>out of town.
>Mike Troast 97 KTM300exc
>
>
>
Mike
I run Unleaded preimium for trail & enduro riding, for MX and real fast open riding I use race gas. In Florida Hare Scrables I had to run race gas due to the deep sand and hot air temp. the altitude here allows us to run a lower octane fuel. in the winter I use the pump gas also , BECAUSE it is oxygenated, the factories use oxygenated fuel in the GP bikes. Any time you can get extra O2, then grab all you can!! but you have to jet for it!
the higher the octane the slower the fuel burns,and can give you poor throttle responce. if you are riding and using the bottom end power a lot then you are not building heat as much and there is less chance of detonation. if you are pinned all the time, the combustion temps are a lot higher so it is easier to get detonation with a low octane fuel
Try mixing pump/race gas and see what works best for your riding.
"IF" you don't need it, don't spend all your cash on the stuff.
Graeme Davies AMA 568408
Denver, Co FTR 6-29654
95' KTM 250SX RMEC 2131
94' XR600
gra...@aol.com
Jeff @ MX SOUTH
>Mike
>I run Unleaded preimium for trail & enduro riding, for MX and real fast open riding I use race gas. In Florida Hare Scrables I had to run race gas due to the deep sand and hot air temp. the altitude here allows us to run a lower octane fuel. in the winter I use the pump gas also , BECAUSE it is oxygenated, the factories use oxygenated fuel in the GP bikes. Any time you can get extra O2, then grab all you can!! but you have to jet for it!
>the higher the octane the slower the fuel burns,and can give you poor throttle responce. if you are riding and using the bottom end power a lot then you are not building heat as much and there is less chance of detonation. if you are pinned all the time, the combustion temps are a lot higher so it is easier to get detonation with a low octane fuel
>Try mixing pump/race gas and see what works best for your riding.
>"IF" you don't need it, don't spend all your cash on the stuff.
>Graeme Davies AMA 568408
>Denver, Co FTR 6-29654
>95' KTM 250SX RMEC 2131
>94' XR600
Graeme,
Klotz makes an oxygenated race gas the they call "Extra". It is
always available. Let me know if you want to try it, I can drop ship
it right to you straight from Klotz.
Rich Rohrich
>>I ask the question because I can't always get out during the week to get race
>>gas and I've been thinking about buying some Klotz concentrate. That way I can
>>just pick up some pump gas to add to it when I fill up the truck on the way
>>out of town.
>I like to use race gas if for no other reason than it comes out of
>drums and is 100% uncontaminated and I know it is the same every time
>I get some.
>MX Tuner
It's importnat to realize that REAL Race Gas like Union76 and Sun Oil products
are designed with a fixed Reid Vapor Pressure (RVP), a fixed Distillation
curve, and a standardized additives package.
All these things will change in pump gas based on time of year, altitude and
what part of the country you're in. Just dumping Klotz concentrate(which is a
good product) into a random batch of pump gas is a tuners worst nightmare. If
you're jetting by the "It hasn't blown up yet" method, than it probably
doesn't matter. But if you take it more seriously, try to find an affordable,
consistent supply of race gas from a sealed container source(ground tanks are
a friggin' nightmare) that works, and stick with it. Holeshot-o-Rama!!
Rich Rohrich
cfm Engineering