Hi guys,

just wondering if anyones got any advice, my sherco 290 (03) is pumping oil from the crankcase breather.

I have replaced the crankcase seals but after a recent trial found i had lost all off the oil, topped it back up with 450ml and sure enough the same problem from the breather.

could this be a fault with the crankcase bearing? or am i clutching at straws cos this bike has had nothing but problems with seals since i had it.

any adivce would be gratfully recieved thanks

could it be centre gasket..dodgy casting/machining crank halfs, does it suck and blow,

I have never heard of this being anything but a seal problem. How old are they, and what brand?

I doubt the bearings would be the issue unless they are terribly loose, being able to move the crankshaft up-down 1mm or so. Probably sound rough too.

Another way to test for excess gearbox vent pressure would be to submerse the end of the tube in a cup of water and look for bubbles.

Edited March 12, 201115 yr by copemech

I have never seen oil go out the breather unless over filled or upside down.