Topic: Engine valves on rebuild

[Lost and Confused]

Hello,  I have a question about valves. I'm rebuilding my 750, I've bought new valves, springs, and retainers and wanted to know if lapping the valve seats is always  neccesary. The dome area of the head had a lot of black soot. Former owner ran it rich, I guess. Thanks for any info.

[tlbranth]

I would check the guides for wear and replace them if necessary and have the valve seats refaced. Then lap very lightly. I'm not a fan of heavy lapping because, if you think about it, lapping wears away the part of the valve seat that's touching at the time. When it gets hot and rides up a tad on the seat, You're into new, unlapped territory a lttle bit.

[lucky]

You must check the valve guides for wear. No use lapping a wobbly valve. Do it the way the book says.

.004 max tolerence.