unburnt fuel/ premix on swingarm

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CanadianKDX220
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unburnt fuel/ premix on swingarm

Post by CanadianKDX220 »

Recently bought 1998 220 from older gent. On first long ride noticed black ooze on swing arm and brake cover. Seems to be coming out of forward joint on PC2 muffler. New to 2stroken. Am I just burning out his build up in cylinder? It has lessened and it was recommended to me that 32:1 was too much so I've backed off.to 27.5:1 . Muffler packing? Shitty gas? Burly rev pipe , boysen carbon fiber reeds, rad valve..any ideas?
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scheckaet
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unburnt fuel/ premix on swingarm

Post by scheckaet »

No offense but, whoever told you to go from 32:1 to 27.5:1 doesn't understand how 2 stroke works...
the words: RICH / LEAN refers to the ratio: fuel / air
27.5:1 is (edited) LEANER than 32:1 (less fuel for the same volume).
that black stuff is the result of an incomplete burn of your mix (gas AND oil)
Your JETTING is off, check my sig for jetting how to, problem easy to solve.
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adam728
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Re: unburnt fuel/ premix on swingarm

Post by adam728 »

scheckaet wrote:No offense but, whoever told you to go from 32:1 to 27.5:1 doesn't understand how 2 stroke works...
the words: RICH / LEAN refers to the ratio: fuel / air
27.5:1 is RICHER than 32:1 (more fuel for the same volume).
that black stuff is the result of an incomplete burn of your mix (gas AND oil)
Your JETTING is off, check my sig for jetting how to, problem easy to solve.
I think you are backwards. 27:1 fuel/oil will have more oil and less fuel for a given flow than 32:1.

But you are right in that it is typically jetting that causes it.

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scheckaet
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unburnt fuel/ premix on swingarm

Post by scheckaet »

:rolleyes:
yup i got it back ward the 1st time but corrected it!
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adam728
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Re: unburnt fuel/ premix on swingarm

Post by adam728 »

scheckaet wrote::rolleyes:
yup i got it back ward the 1st time but corrected it!
It's easy to get lost in the whole "A/F vs oil mix" ratio thing. Been there many times.

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CanadianKDX220
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Re: unburnt fuel/ premix on swingarm

Post by CanadianKDX220 »

270 mils of oil per 1 litre of gas is more then 320 mils? Hmm
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Re: unburnt fuel/ premix on swingarm

Post by CanadianKDX220 »

Oops . Sorri guys..found a great metric chart that tells me I'm running 40:1.
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scheckaet
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unburnt fuel/ premix on swingarm

Post by scheckaet »

please read
read rich vs lean
and spooge threads in the "newb thread"
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kawagumby
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Re: unburnt fuel/ premix on swingarm

Post by kawagumby »

FWIW my 200 is jetted spot-on with an RB modded striker carb. I even custom-modified the needle to get perfect linear throttle control I couldn't get with an array of available needle sizes. The bike just sings...BUT...it is the spoogiest bike I've ever owned. I think spooge is as much due the kind of riding you do as much as jetting/oil mix. If you are into tight stuff where you're shifting a lot , braking hard, accelerating etc. the exhaust volume/speed is ever changing which leads to the heavier oils condensing on the cooler elements of the exhaust system. Same goes if you are riding in a more relaxed mode.
The most maintenance I do on my KDX's is cleaning spooge after every ride LOL...
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
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Re: unburnt fuel/ premix on swingarm

Post by sms »

May want to check your packing in your silencer my bike did same thing when I first got it changed out old oil soaked packing and good now.
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Re: unburnt fuel/ premix on swingarm

Post by KarlP »

Yeah, I'd change the packing first and see how it does. You may have a faster riding style than the PO and are blowing out an accumulation. It would be nice to know what jetting is in there if only for your own reference.
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