Valve Clearance

2003 XR650R, 150 miles

When checking Valve clearance the Honda manual (pg 3-8) has you roll the fly wheel CCW 2-3 turns to align the "T" mark with the index notch. And then make sure you are at TDC on compression. (decompressor has free play)

When I roll the engine CCW 2-3 turns I observe the intake valves open with the piston lowering in the cylinder(intake stroke). Intake valves close(exhausts are already closed), piston starts coming up in the cylinder (compression stroke) "T" mark lines up, but piston doesnt reach TDC for about another 1/8 inch of stroke.

At this point the intake and exhust valves are on the flat part of the cam so the valve clearance is not impacted, but whats up with the manual requiring the "T" to be lined up with the index and the piston at TDC on compression(my engine does not line up).

Also while adjusting the valve clearance the intakes were right on .006 with a slight drag on the feeler gauge. The exhausts were a little tight I could get a .008 gauge in but it was real tight so I lossened the exhausts up. Now I have some tappet noise. I would rather have some tappet noise rather than tight valves. Part of the exhaust clearance problem was probably the straight feeler gauge I was using. It is hard to get at the exhausts because of where they are located. I have ordered some bent tip Motion .006 and .008 feelers. The exhausts should tighten up some with time right? Comments?

In my experiences the intakes tightened up first and the exhaust were always ok. I think that's the normal consensus also. These bikes should sound like a fine tuned sewing machine when running. If you've got an aluminum skidplate it just magnifies it. I put a bead of silicone on my framerails as someone else suggested and it helped the sound a bit.

Don't know about the T - possibly easier to explain than "make sure the cam lobe is on the flat spot?" :thumbsup:

I line the t up with the notch on the motor casing as the manual states. Haven't had an issue yet. You need to pull the stator case off though. The site window is small and tough to see.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now