kz750 four head/block machining

My 1980 kz750 4 cylinder is leaking a little bit of oil between the head and block. I am sure this is due to a scratch that was put into one or the other during a previous rebuild. Does anyone know how much material I can safely remove from the head and/or the block?

You can't take much off the head before hitting the valve seats. The cylinder is less restrictive.

Sounds like you are getting ahead of yourself. Pull the engine down and check everything out and then decide what needs to be done.

One thing I do know is that aftermarket gaskets range in quality from passable to pure crap. Spending a little extra and getting proper OEM Kawasaki gaskets is the way to go if you value oil tightness.

Thanks for the tips, I'll make sure to look it over before I send it out to get it cut

I ended up taking .003" off the head and .007" off the top of the block. The head machining cut into the valve seals a bit but it didn't go deep enough to get into the contact areas. Bike's back together and runs great

Awesome, thanks for sharing the results!