1979 YZ250 Troubleshooting help

Good Day!  


I have a 1979 YZ250 that I am trying to get running right but I am having some issues.  First off I have already changed the crankcase oil, and cleaned out all fuel lines gas tank etc and started with the 32:1 ratio of premium fuel to Bel ray 2 cycle oil.  I also removed the exhaust and moved the piston to TDC and rings, piston and cylinder look really clean and good, however I noticed that the compression just seemed low.  Like during my kick starting a few kicks would be hard solid with compression and then a few would be easy.  Just seemed weird.  My symptoms are below and thanks in advance:


-Smoking like a wildfire, thick white smoke and lots of it

-Oil Spray after test ride on silencer, and rear left swing arm.  Oil is dark. not translucent

-While riding it feels like nothing is really happening like its missing in first and second and it seems like midway through second I 

get that smooth running fast motor almost power bandish, but then when I let off it feels like its missing



I was thinking that it might be running rich and that the Mikuni Carb is just dirty and is dumping fuel in the cylinder and not burning off then blowing out of my exhaust.  My second thought was crank seals.  


Any thoughts?  Advice?  Steps?  My manual is in the mail.


Thank you again 

David Lindley

Probably crank seals, you may also want to check your reed petals are sealing properly.

That would be a YZ250F.

I'd start with carb. Make sure the float isn't sticking, clean it and make sure all passage ways are clear. Sounds to me like it's just loading up

With any engine, old or new, the first thing I would check would be for air leaks. This is super simple to do, and will tell you the integrity of the complete bottom end chamber.

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