im having problems with the plugs fouling out quick. i rebuilt the motor and carb not long ago and
can not figure ouy why it fouls so quick. the plugs are dry when i take them out but they are black.could it have something to do with the vales?

 

sounds like to me your running too rich. What size jet are you useing and where is your needle jet clip at. I would try to move that clip up a notch and see how it runs then. If it runs a little better move it up another notch and see how it runs.

 

i have tried the needle jet in the top,middle, and bottom. no change
i think it has a # 35 jet, but my plugs are dry. i rode it this morning at it fould out in 10 min.

 

my friends did the same thing but he need new rings.. and you said u just rebuilt it not long ago so im not sure.

 

it could be your valve seals because the oil that goes up in the cam to lubricate it might be seeping back threw the valve stems and into the piston area. im haveing the same problem but mine dosent foul them that fast mine takes about 6 hours of riding to and i know i need new valve seals. what all did you rebuild on it?

 

i honed the block. put new rings, gaskets, timing chain, and carb. kit.
when i take the plug out i can whipe the black off pretty easy.

 

then it might be your valve seals

 

If it is your valve seats leakin then your plug should smell like burnt oil... Does it smoke at all???

 

no smoke.

 

How is the compression?

Also, a hotter plug might help.