Motorcycle Repair: Honda valve adjustment, honda valve adjustment, feeler gauge

Question
Hi Bill,
I'm trying to understand the proper way to adjust the valves in a 1982 CB650SC SOHC Nighthawk.

My delima lay in the fact that the set screw/nut are undernieth the valve cover, as is the valve stem/ rocker arms. This makes a feeler gauge, and other tools very hard to work around.

This may be one for more specialized tools. What or how would you do this job?
Thank you,
Rick

Answer
Rick, for the basics, go here
http://www.dansmc.com/valveclearence.htm

For specialty tools to make the job easier, see this site:

http://www.dual-star.com/index2/Tools/Tappet%20Feeler%20Gauges.htm

Be sure that you are checking the valves when they are loose at the 1-4 or 2-3 marks on the flywheel. If you turn the flywheel to T and the valves are not loose, then turn the motor over ONE turn and check again. You can pretty much do them all in two turns. Check and adjust all the valves that are loose at the F mark alignment, turn motor over one turn and check the rest of them.

You may have to remove the horn or anything that is directly in the way of the tappet covers. The bent gauges are the way to go, though. Should be available at most m/c shops. Get a .002-.003" combination gauge for the intake/exhaust clearances.

Check the camchain tensioner, too. Turn motor about 90 degrees past TDC #1 cylinder compression, loosen the tensioner bolt/nut about a turn, then tighten again. Watch the valves as you turn the motor back and forth with a wrench to see if there is any "slack" between the cam and crankshaft. Adjust until they both follow each other in either direction, without delay. You may want to check the mechanical spark advancer to be sure that it is functioning properly, as well. Grab the end of it and twist it to check for proper motion and return with spring pressure.

Manuals are often on Ebay or order OEM manual from www.helminc.com

Bill Silver