2001 CR250 Exhaust Valve Drive shaft

[Mike_socal]

How much up and down movement should there be on the exhaust valve drive shaft? I have some and I think it's the cause of an air leak(I have air leaking from the exhaust valve pinion shaft hole). I loosened the allen screw and adjusted the up and down play out of the shaft. Even with no up and down movement I think there's enough height on the exhaust valve pinion shaft pin to properly engage the drive shaft crow's foot thing but I'm only eyeballing it as I don't have a gasket set handy to put the cylinder back on. I also greased the shaft and it's bushing in hope this seals any air escaping down the shaft hole. The manual says to tighten the exhaust valve assembly allen screw after the cylinder is put on but it doesn't say to lift the drive shaft, push down on the valve assembly or how much up and down movement of the drive shaft there should be. Any opinions?

 

[Mike_socal]

Well I got the cylinder and head put back on and the pinion shaft no longer leaks air. So the combination of grease and adjusting the up and down movement out of the exhaust valve drive shaft sealed the air leak. It now leaks about 1.5 psi over 5 minutes. I think there might be a very slight leak in the left crank seal but it doesn't seem like enough to start tearing apart the left side.