Done my valve check...Question?

After 5 hours on bike, I found the intakes were within spec.

The exaust were both at 20mm. which is at the tight end of spec. So I pulled out the two shims and they were both #182 pads, so I replaced them with #175 pads. My clearance now is 27mm a little on the loose side. Is this going to be o-k ? I was figuring that the exaust valves would stretch the most from the heat, makeing them fall out of spec faster if I would have left them both at 20mm. Maybe I should have put 180s in there ?

The manufactures specs take care of average conditions that they expect the engine to be in such as heat. Therefore as long as you are within their spec.s on the vavle adjustment you will be fine. A pro racer might try to get it 100% perfect but, they spend a lot more on motor work.


The range spec. on the exaust valves according to the book should be 20mm to 25mm, mine is at 27mm after I changed shims. I figure better to be to loose than to tight!

Well that depends...

Does an exhaust valve typically tighten up or loosen up over time?

That would be my deciding factor on being on one extreme or the other.

I've run into the same problem and have run the valves on the loose side without any problems. The valves always tighten up (valves receed into the head), so the next time you look at them chances are they will be bang on. Rule of thumb - better loose than tight. I wouldn't loose any sleep over it.

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