New Member Carb Questions

[poorboy6977]

Hey Guys, Ive got an 86 250r, stock motor and carb. For some reason its VERY picky about air/fuel. I keep fouling plugs right and left. Last weekend i went through 5 plugs!!! Any suggestions? Thanks.

[kildea250r]

What are you runnin for your mixture? What oil? What's your jetting? What heat range plug are you runnin?

[Yamaha_Freak]

Go down 1 or 2 jet sizes

[kildea250r]

Do you bog the engine when you ride? I mix 20:1 still with 110 octane. 155 main jet and maxim synthetic oil. A br9es ngk plug and held wide open till you find a corner. Pushed her home once and learned not to bog again.

[poorboy6977]

I run Klotz Benol, 40:1, NGKB8ES, and i drag race most of the time with a few trails here and there.i NEVER bog. It will show no signs of fouling......then it just dies.

[poorboy6977]

Oh, Im running stock jets with FMF fatty and power core II and a K&N

[bones9401]

jetting big guy. alter the air intake and/or the exhaust and your stock jetting will also have to be altered. i have a similar set up as far as exhaust and filter go and i had to fiddle with my carb for days to get it right. i run 40:1 also and i can run
b8es or b9es and never foul a plug. it was really trial and error with the jetting and to be honest with you i don't remember what i ended up with.

[poorboy6977]

I thought since i added more air flow it would make it leaner, not rich. Just doesnt seem right to have to go smaller than stock onthe main, or are you referring to the pilot. My first REAL 2-stroke. Never had this problem before.

[kildea250r]

Try runnin a 155 main and a 42 slow jet. Set the air screw about 1 1/2 turns out and run the jet needle in the 4th groove. This is the set-up I run with a fmf fatty and silencer. I'm bored thirty over with a open element filter. No problems ever for me. This should get you close then fine tune with your air screw.