yz85 spark plug fouling

[tonimarie613]

Hi,I just purchased a used 2004 yz85. It runs fine for a day or two, then the spark plug fouls, we clean the plug and it starts but will not run like before. Then it just dies within a short time. When I put a new plug in it does the same thing. Runs for a day or two and then it dies again. We are using BR10eg/NGK spark plug. 32:1 gas/oil ratio. If anyone could help me with this problem I would really appreciate it. Thanks, Tonimarie

[trickSX]

Try going down to a BR93g, but you just might not be riding it hard enough

[mtk]

Your jetting is wrong.

Changing spark plugs is treating the symptoms, not the actual disease. Fix your jetting and plugs will last indefinitely.

[Yzrider054]

you are either not running it hard enough or the jetting is off ! remeber a perfectly jetted 2 stroke will go a long ways on a plug.

[SirFallsALot243]

You should be able to ride it as slow as you want without fouling a plug. A plug shouldnt ever foul from not riding it hard enough. Jet it.

[ShaneRider]

It's more than likely your jetting. Get that fixed.

[robertc]

its' not jetting. when i first got my 2 stroke i fould about 5 plugs until i learned to ride it. If ur just riding around slow, every few minuts, pull in the clutch and revv it. It has been about 4 months since i've fouled a plug once i learned how to ride a 2 stroke.

[Silver_Fox]

Originally Posted by robertc

its' not jetting. .

Yes it is.

[FFRacing11x]

Originally Posted by robertc

its' not jetting. when i first got my 2 stroke i fould about 5 plugs until i learned to ride it. If ur just riding around slow, every few minuts, pull in the clutch and revv it. It has been about 4 months since i've fouled a plug once i learned how to ride a 2 stroke.

You might have learned how to ride it(??), but you haven't learned how to jet it!

[Mr.Boof]

go to a 132 main jet... it happpened on my friends yz

[mtk]

Originally Posted by robertc

its' not jetting. when i first got my 2 stroke i fould about 5 plugs until i learned to ride it. If ur just riding around slow, every few minuts, pull in the clutch and revv it. It has been about 4 months since i've fouled a plug once i learned how to ride a 2 stroke.

Short and sweet: you're wrong.

Your jetting is off and rather than correct it, you're trying to limp around the problem.

Your options are: A) fix it right by rejetting, or B) continue to do the stupid "clutch in and rev it" BS in an effort to keep from fouling plugs.

[Doom Crew]

Originally Posted by mtk

Short and sweet: you're wrong.

Your jetting is off and rather than correct it, you're trying to limp around the problem.

Your options are: A) fix it right by rejetting, or B) continue to do the stupid "clutch in and rev it" BS in an effort to keep from fouling plugs.

Yep, my buddy had this problem just rejet it and you should be fine.

[ShaneRider]

It won't kill you if you feather the clutch a little bit even when your jetting is fixed. Feathering will get you on the power faster.

[robertc]

well, i guess you can re-jet. i didn't on my bike but since everyone seems to say that u should, i guess they are right.

[mad_biker]

i'd probly just get the next 3 smaller main jets and start with the bigger of the three and go smaller if needed .

[ossagp]

There is a good post by Faded on setting a float. Buy all the jets and turn all the screws you want, and you will still not be as crisp as you could be if that simple item was set right. From there I would work with the low speed screw. Turning it in will place more fuel in the fuel air mix and likely increase your fouling. Turning it out will lean out the low speed circuit. If you have to go more than 2.5 out, consider the next smaller pilot jet.

There are lots of threads on here about jetting. Some are pretty good.

Jetting is on a "per rider" basis. Most any rig can be jetted for the type of riding and the type of rider.

I see nothing wrong with changing a heat range to get a certain affect, but changing it because you are fouling plugs is as MTK said, just treating the symptom.