Excessive smoke (please help!)

[sbleakle]

My '89 KX250 smokes like crazy and I've been going on the assumption that it has a leaky crank seal. Trying to build a pressure tester but haven't found a suitable plug for the exhaust port. Here's some specifics on the bike and I do appreciate any assistance:

Compression: 173 psi
Fuel: 32:1 Yamalube semi-synthetic/89 octane pump gas.
Carb: New Keihin PWK39 from Carb Parts Warehouse (prejetted by them and I didn't check what they put in it).

Bike smoked when I bought it (with the old stock carb). I screwed up and soaked the carb body, killing those special o-rings, hence new carb.

It sat from 7/02 until last weekend when I revived it. Some yahoo had stripped the tranny drainplug in the past so over time it leaks it all out. I started the motor the other day with no visible oil in the site glass since I figured I was just testing the motor and not the drivetrain. The glass is low on the engine, maybe lower than the crank seal itself. It still smoked like crazy so how can it be burning tranny fluid if it didn't have any in it? I topped up the tranny and it made no difference in the amount of smoke. What else could be causing this embarrasing excess smoke?? I'm afraid to take the thing into public but would love to ride it.

Thanks!
Steve Bleakley
A BMW guy with a few old dirtbikes.

 

[j_freak]

If it were me I'd double check the jetting before I did anything else...

Also make sure the air filter isn't soaking wet with oil

 

[kawdude]

I agree check the jetting first and the oil filter. If it smoking and the there's no oil in the bottom end then obviously it's not coming from there. It could be leaking between the cases. I'm not positive but you may be able to change the main seals on that bike from the out side. I have a 94 kx500 and I have to split the cases. I would assume that the age of the bike says that you'd be better off just replacing the seals to eliminate them from the equation. But do start with the jetting and filter.