Originally Posted by simonpig
Interesting. I had a feeling it might be the hydraulic cam chain tensioner. The only thing is that upon inspection, you cant tell its working or not since it relies on oil pressure.
The cam sprockets look ok to me, and not worn at all. I was going to pull the rotor today and pull the chain to compare it to a new one to see. You mentioned measuring it while on the crank. How do you do that?
FYI, just want to note this the WR250R dual sport model and not the 250F racing yamaha's. Does this manual chain tensioner work on my bike?
I've been in touch. I am getting a gasket to do the job, we'll communicate on this. I've done the CBRF/F2 and the CBRF3/F4/F4i tensioners which used oil pressure. They just block off the flow, no problem.
There should be a spec for measuring the cam chain while on the bike if it is a dual overhead cam. It is measured from one pin to another over a certain number of teeth. Unless you have several thousand miles with a junk tensioner, I'm betting it's still good.