KX85 Fouling Plugs

[JG2448]

My son's kx85 is fouling plugs almost 1 every time he rides it. We are running the oil mixture 32:1.He is staying in the throttle most of the time. However it still puts out spooge on the end of the pipe. I did notice the other day cleaning it that the air mixture screw is staying wet around it like there is gas seeping (Not Dripping). I noticed today it was running fine and I had him rev it up to clear it out real good before he shut it off. He started it back up 15 min later and the plug fouled just after starting it.
Is the gas around the air mixture screw normal? Or could this mean the float is a little out of adjustment?

 

[TimberPig]

This means the jetting of the bike is supplying too much fuel, making their air/fuel mix too rich. You need to rejet the bike, and the problem will go away. There are good instructions in a sticky posted in the 2 stroke forum, on how to jet a bike. Go there, read them, get some brass and tune the bike properly, and your problem will be gone.

 

[JG2448]

That was what the dealer suggested. Just wanted to make sure I was on the right track. Going to let the dealer do it. I have rebuilt and jeted Holley carbs on cars but never messed with one on a bike, but my question is it normal for the air mixture screw to stay wet around it? I was thinking that maybe the float might be set a little to high since the air mixture screw was wet.

 

[mele63]

I can't answer your question about the air screw, but if the dealer is going to tune it he should check the float bowl height. From what I've read, that's part of the carb tuning process.

I'm going to re-jet my KX125 this weekend. This will be my first time but like you, I've rebuilt automotive carbs in the old days (not Holly but Carter Thermoquad). I think there is only so much the dealer can do without having an opportunity to get out and ride it.

 

[TimberPig]

If there is mix seeping around the airscrew, my thoughts are it is probably backed out to the limit trying to lean out the pilot circuit. Fuel is backing up into it, and seeping out around the threads. While the carb is apart, they can check the float level, and readjust the airscrew so that it is not set at its leanest where it is trying to fall out of the carb.

 

[kawicam125]

like the others said, you need to rejet your bike. clearing it out before you shut it off is a very bad thing. you should clear it out before you ride, not before you shut it off. clearing then shutting just loads up the bike, thats why he fouled a plug after just starting it.

 

[JG2448]

My air mixture screw is about 1.5 turns out, from what I have read and what the dealer said that was a good starting point for seting the mixture air mixture screw I haven't really turned it much.
My son raced this weekend he had 4 practices before the race he fouled 2 BR9 plugs. The ceramic electrode was solid black and wet. Another Dad recommended trying a BR8 so I sent the wife to pickup a couple and I put the BR8 plug in and he ran 4 moto's I checked it after each moto to make sure it wasn't runnining two lean. The ceramic electrode stayed a dark brown and the bike ran fine all night. I think im still going to let the dealer rejet the bike. I'm kind of scared to keep running the BR8 plug. Thanks for all of your help.