QuestionI can't find a book on a 82 honda 650 (nighthawk) It has 20000 miles and runs great but makes a little noise at idle, I supect the cam chain but don't know the adjustment specs. Any advice?
AnswerJoe, turn the motor over so that the crankshaft is at about 15 degrees after TDC compression on the left, #1 cylinder. At that point you will see that there is a lock nut and slotted screw looking tensioner bolt at the base of the cylinder block. Loosen it, wiggle the bolt back and forth with a sharp edges screwdriver, to ensure that the bolt is loose, then tighten the nut up again, gently. The tensioner is spring loaded.
Go here:
http://www.powersportspro.com/partsfish/login.asp
Signup login, find the HONDA CB650 microfiche illustration labled camchain tensioner and check out the details for yourself.
After the adjustment, you can put a wrench on the end of the crankshaft and "rock" it back and forth very slightly.
If the camchain is still loose, there will be a slight "pause" and some slack before the crankshaft catches up with the chain slack. No slack means a properly tightened chain... and hopefully less noise. Don't forget to check the valve clearances, while you are doing maintenance. .002" on intakes and .003" on exhausts, cold on their respective compression strokes TDC.
More links and info at www.sohc4.us
Bill Silver
www.vintagehonda.com
