Smoking alot and spoogy exhaust

coolbreeze

Member
Nov 22, 2004
1
0
Hi all,
I just repacked my muffler and got my bike set up after purchasing it used, 1991 KX 250 H2. The idle mixture is 1 and a half turns out, idles fine and starts on first kick. When I pull the plug, it is soaked with oil around it but I have put about 6 hours of trail riding time on it without any foul outs. When the bike first starts, the smoke is almost unbearable and I clear out anyone who is in the surrounding area. Mix is 40:1 with yamalube or red line. Smoke cuts down after warming up but still seems like a lot. The exhaust is dripping with oil but 40:1 seems somewhat conservative. I'm not sure when the top end was last rebuilt, but I'm certain it was sometime ago. The bike is running great but the smoke surely indicates something is wrong. The coolant level is not decreasing so I'm not sure what will remedy the situation.
Thanks for any insight
 

Jeff Gilbert

N. Texas SP
LIFETIME SPONSOR
Oct 20, 2000
2,963
2
Your bike is intended to be revved out probably more than you are doing on the trails. It's normal for 2-strokes to smoke when 1st started and lugged around, won't hurt it a bit except yoou may foul a plug. If you're going to be doing trail riding and lugging the engine, you will want to jet it correctly. Sounds to me like the previous owner (if he was from your area) has the bike jetted for his conditions & riding style. To learn about jetting take a look at Eric Gores website or the KDX forum, lots of good info on there.
 

darringer

LIFETIME SPONSOR
Dec 2, 2001
1,029
0
If your right side crank seal is leaking, it will smoke like crazy. Maybe check your tranny oil to see if it's disappearing. It could be getting drawn into the combustion chamber through that right side seal. Drain and refill the tranny to the correct level, and check frequently to see if it drops. Or, it may just be a simple jetting issue.
 
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