Honda cb350f

[oldmanriver]

Hey all, Im new to this forum but Ive heard good things. I have a 72 350F. I recently had the top end redone. Cylinders bored with Japanese Big Bore kit (396). Head machined and completely redone (valve seats recut, valves refaced, should be good as new) good compression, but its still burning oil like mad. Hoping I can get some thoughts here. Most of what I've read and heard seems to be valve guide issues...seals probably. The guy that did the work says I need to ride it for 500 miles for a break in, but I dont think thats right...shouldnt be burning oil.....right.....am I nutz here?

 

[mydlyfkryzis]

If the CB350f uses valves like the twins in design, they valves cannot be refaced. the hardened surface is only 0.002 thick. A reface will remove the hardening, and they will wear out quickly. You should replace the valves.

I may be wrong on this, but all the other Honda's of the era had surface hardened valves that could not be refaced. check your factory manual for that.

 

[oldmanriver]

Thanks for the reply..i havr not heard that but its def...worth some research.

 

[crazypj]

Pre 1977 valves had thicker hardening.
Stellite welded face on exhaust valves that could be ground but I prefer not to.
Don't grind intake valves