Valve cover pressure??????

[68chevy]

my bike keeps pushing the gasket out by the end of the cams. must be building up pressure. any ideas why? is there a vent i need to check?

[DonTZ125]

It could be swollen with age / chemicals. There is a crankcase breather on the top of the transmission area behind the carbs; this should be plumbed to the airbox.

[pefrey]

It also could be that somebody tightened the cover's bolts too tight and squished the gasket. The cover bolts don't need to be very tight.

[68chevy]

idiot owner before me had the breather vent tube pluged off with a bolt.........who would of figured!! thanks for help and ideas guys