honda atc 90 (need help)

[dankclimes]

I found out my 1978 Honda atc 90 has a 54mm piston in it and was wondering if stock 90cc head gasket will work with the over sized bore and piston? also when adjusting valves if you don't have a .002 feeler gauge is there a general rule for adjusting the valves correctly or close enough?

[bigworm626]

climes,
Welcome, indeed stock head gasket should not be problem when using an oversized bore & pistons. I would recommend a feeler gauge evertime. Is your bike running at the moment for checking the valves?

[dankclimes]

no my bike isn't running right now. i have the engine disassembled I was thinking about throwing a bigger piston in because of its inefficient top end speed in 4th gear only to find out it already had a larger piston installed. After finding that out I decided to clean every thing up replace all gaskets and check the condition of valves, piston, cylinder wall, and I lapped my valves while i had taken apart. My valves are way off now because I accidentally measured them to .020 with a feeler gauge, oops. My bike wouldn't idle no matter what air fuel mixture I had the carburetor set at do i need a bigger carb for that piston or could it be just a timing issue? The new head gasket im trying to install over laps the cylinder about 2mm all the way around but you think it shouldnt be an issue?

[dankclimes]

Thanks for the quick reply earlier and the free advise it is greatly appreciated.

[dankclimes]

trying to get this trike ready for mud fest