Optical Illusion or Reality

I bought a YZ cam (according to official Yamaha part number) for my WR450F to change the timing to YZ. My mechanic who´s about the install the part says that he has compared the two parts (WR cam and new YZ cam) and say they are identical, just the dot is 1 tooth advanced. I told him that according to what I have read on this site the difference should be more, because simply advancing one tooth will disable the auto decompression for a 450 (different than the 400/426) He says that there is no optical difference to the position of the auto-decompression vs. the curve on the camshaft. Is this an optical illusion from my mechanic. I am afraid that I have bought the wrong cam than although the part number is the YZ one and the dot is one tooth advance. What should I do?

The YZ cam has a different length decompression pin to compensate for the change in timing. It's subtle but if you look closely you can visually see the difference.

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