oil leak from airbox?

[Justin B.]

If the breather valve is stuck closed then I suppose the crankcase pressure could cause all sorts of oil leaks.  I know that in cars when the PCV valve sticks shut it can be a real mess as oil eventually blows past seals, etc...   Also, make sure you haven't overfilled the crankcase.

[Bob_Roller]

You're right about crankcase pressure, remove the oil dipstick, start the engine, and see how much airflow you get out of the dipstick hole !!!!!!!!!!!!

 Looks like an '81 or later bike, it should have the 'reed' type ventilation valve, not very likely to stick closed.

[steve_wicks]

According to chassis number it is a 81 model.

I'll whip off the airbox this weekend and see where this damn pcv valve thing is and what I can do.

I have to admit I find the $70 Haynes manual only slightly more useful than a telephone directory.....

[Bob_Roller]

The 'PCV' valve is under the top cover of the engine, next to the starter.

[steve_wicks]

Since I fiddled with crank breather pipes and airbox my oill leak has all but disappeared. It seems there were two issues:
First was the pipe from the breather going into the airbox was kinked and split which effectively blocked it.
The other problem is that oil was new and at 3/4 full mark and with the build up of pressure in the crankcase, it all started oozing out of weak areas.

[nhmaf]

That's good that you found the likely suspect !

It is very rare that the actual valves on the post-1980 bike fail and stick closed, but it is much more likely that the plumbing to which it is connected gets blocked up, as you discovered.   The air pressure has got to go somewhere !