Detonation city. Not high enuff octane. Your jetting is on the rich side but fuel does not have enuff octane.
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do u think i should try to run a bigger squish ??? or what i should do to solved problem
Concept Carbon
New member
what is your squish
The squish size is only part of the equation. Combustion chamber is a big part of it. Bottom line your fuel quality/octane is not good enuff for your sled.
terret725
New member
ive run .050 no problem on 93 and my brother with .048 for 7000 miles. looks more like a lean burn to me. its on the exhaust side. which 90% of the time means lean. altho ur piston wash doenst look bad not saying it can be detination but just my position tells me lean. id check for air leaks just to be safe.
i guess ill put a bit more squish and take some compression out of it ...and hope for the best
i'm sure its not a air leak cause all of those 3 piston melt like that in the first time..this time i put bigger jet in it and only one piston melt the top of it
ill wait to see what don think about them
any idea mr viper ??
what pilot jets and wheres the needles set at?
when you droop the exh edge it is from being lean, although the wash on pistons look rich, but if the midrange circuit isnt rich enuff no matter how big the main is the first mid throttle run you make can do this.
is the airbox modded?
when you droop the exh edge it is from being lean, although the wash on pistons look rich, but if the midrange circuit isnt rich enuff no matter how big the main is the first mid throttle run you make can do this.
is the airbox modded?
pilot jet are 45 set at 1 turn more than that the sled is aways run like on choke always hesitate are to explain but i hope u understand... needle clip have been lower one clip .. not sure but i think that happend on wide open throttle...cause i could feel something grabbing in the motor so i let the throttle back off and discover that again .. do u think i should put back stock air box ..
ok, needle is in the 4th clip down from the top? but where are the plastic shims placed at?
the only thing being done to the airbox should be some holes in the upper box top under the foam,the middle shelf must remain stock, untouched with the 3 baffle tubes, if thats not like that, it needs to be changed!
the only thing being done to the airbox should be some holes in the upper box top under the foam,the middle shelf must remain stock, untouched with the 3 baffle tubes, if thats not like that, it needs to be changed!
ok ill change the second parts of the air box plastic ...shims are under the clip
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well if i'm ritch i guess putting back a stock air box and maybe put that clip in the 5 groove from the top should solved my problem ?? its sounds like went it switch from full throttle too midrange circuit it turn lean is in it ???
Yama49601
New member
Putting the clip farther from the top makes it even richer. The closer the clip is to the top of the needle the leaner it will be. Also, taking the shelf out of the airbox leans it out and makes it a lot harder to get jetted right. And I know you said you're putting it back in or something but I meant before when you had it out would have leaned out whatever jetting was in there before.
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well its the second time piston burn that way .. so i try to figure why it does that ... so ill put back the air box stock with the same jetting its in right now 153.8 .. i guess it run lean somehow somewhere ...but piston seem to indicate that it run ritch.. i guess the difference is huge went u open up the air box bettween mid and full throttle