To lap or not to lap

[97af]

Ok guys,the B4 has 16 new valves,16 new valve stem seals,32 new springs and of course 32 new cotters.Now the manual calls for NO Lapping after new valve seats are cut.I did not cut new seats. The valve seat surfaces are flawless but they do have 13000 or so miles of the old valves slamming into them.I'd rather not do it but if its neccesary,I will.As the subject says..To lap or not to lap? That is the question......

[pmackie]

Ideally you would have the valve seats "touched up" by someone with a set of of proper angle cutters. f(frequently grinding stones).

I cannot speak for the Bandit 400 engine, but many older Japanese engines' valves are only surface hardened (usually carborized) and any significant lapping removes some of the hardened surface, reducing the life of the valve. This is usually why lapping is NOT recommended.

A local shop should be able to touch up the seats for a pretty nominal fee? This should result in maximum sealing, power and engine life.

[gsxr400 racer]

stick two valves in and put fluid in port hold valves tight see if it leaks :yikes:if it dont