250 kx 250 two stroke blowing too much oil out exhaust?

I just bought an 09 kx 250f aluminum frame with a 04 kx 250 motor (kx250af). I have only rode the bike once up my road for about 5 minutes. When i got back to the garage the brand new back fender was painted black. I know this is common with a two stroke but this is a little extreme. The bike has a brand new top end in it and the oil gas mix is 32:1 which is usually what it should be I think. I also believe the bike is jetted good. It also has a brand new silencer. So what else could be the problem? Any ideas would be much appreciated.
 

James

Staff member
I just bought an 09 kx 250f aluminum frame with a 04 kx 250 motor (kx250af). I have only rode the bike once up my road for about 5 minutes. When i got back to the garage the brand new back fender was painted black. I know this is common with a two stroke but this is a little extreme. The bike has a brand new top end in it and the oil gas mix is 32:1 which is usually what it should be I think. I also believe the bike is jetted good. It also has a brand new silencer. So what else could be the problem? Any ideas would be much appreciated.
Sounds like a sweet ride, any pictures to share with us?

Have you tried changing the oil mixture ratio and where did you get the 32:1 ratio from, the manual or previous bike? That's about the only thing I can think of, then again I'm a 4 stroke guy. :P
 
I just bought an 09 kx 250f aluminum frame with a 04 kx 250 motor (kx250af). I have only rode the bike once up my road for about 5 minutes. When i got back to the garage the brand new back fender was painted black. I know this is common with a two stroke but this is a little extreme. The bike has a brand new top end in it and the oil gas mix is 32:1 which is usually what it should be I think. I also believe the bike is jetted good. It also has a brand new silencer. So what else could be the problem? Any ideas would be much appreciated.
Sounds like the fuel mixture, maybe drain the tank and the carb, check out the jetting and compare it to stock, and change premix and or your ratio.
 
if the piston rings are warn you will never get rid of the spooge:prof: I read back through your post. If the top end is new, post up the jetting that is in there now and what is factory jetting.
 
Lean it by jetting or back the air screw out some. 32:1 is what you want. You have to be in the pipe hard not to get spooge. The harder I ride the less I have.Don't rule out the crank seal on the clutch side> It can be leaking trans oil into you crank chamber mixing in with the premix. it will cause all kinds of spooge. I would drain and fill you trans case with the correct amount and then after a couple rides check it to make sure you have the same amount.
 
40:1 is fine unless he is running the bike really hard. For the average rider 40:1 is more than sufficient. Stewart or Carmichael that's another story. I agree with these guys that you should check out your jetting first though.
 
It idles great. I ride the bike pretty hard so im a bit nervous about leaning the mixture. The bike has a new top end so its not the rings. I guess Ill look in to the jetting.
 
Lean it by jetting or back the air screw out some. 32:1 is what you want. You have to be in the pipe hard not to get spooge. The harder I ride the less I have.Don't rule out the crank seal on the clutch side> It can be leaking trans oil into you crank chamber mixing in with the premix. it will cause all kinds of spooge. I would drain and fill you trans case with the correct amount and then after a couple rides check it to make sure you have the same amount.
Thanks, didnt think of that. gonna ride it tomorrow.
 
32:1 is the mixture I have ran in all my two stroke biikes that i remember, although I havent had one in a few years. Im not sure how to upload pics. The picture attachment asks for a web address :noidea:
 
if your bike idles do not lean out the pilot circuit, start with the needle and lower it 1 position, so raise the clip up 1 notch from where it is now
 
Adjust the idle to best idle speed. If you are not out more than one turn you need a richer pilot.If more than 2.5 turns need a leaner pilot.
 
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