2004 yz450f cam timing?

Im about to buy a yz450f for 1000 that only has cam timing issues. The guy replaced the cam chain and tensioner jisy could not get the timing right. Would it be an easy fix? Could anyonr possibly post a link with instructions on how to set the timing. I have the tools to do it just dont know how. Thanks!!





Remove the two plugs in the left crankcase cover and run the engine up against the compression stroke.  Then, using a socket on the crank, advance it to TDC.  There are 3 marks on the flywheel.  Reading from left to right, the first two (usually connected by a horizontal mark) are for ignition timing ;ignore them and line up the third one with the index on the case.  NOTE: if the PO installed a weighted flywheel, the marks will not be visible.  In that case, pull the spark plug and find TDC with a Phillips screwdriver.


At that position, the cams should look as follows:  There are two marks on the exhaust cam; one should be at 9:00 o'clock and the other at 12:00, with the 9:00 mark aligned with the head surface.  The intake should have 3, "E" "." and "I", with the "I" at 3:00 o'clock and aligned with the gasket deck on top of the head.  The intake may only have two marks, in which case they are positioned at 12:00 and 3:00.

I just did the valve clearances on my 04 YZ450. I hadn't disturbed the timing chain on the crank gear so it wasn't like timing it from scratch. A special cover means it was easier to find TDC with a probe - I used a small Allen key. I did find it trickier to get the cams back in to position correctly aligned than I expected. The first attempt ended up with the exhaust cam one tooth out. Being more used to a Gilera bialbero motor with a long rubber belt and sprung tensioner I had not paid enough attention to the chain tension. Once the manual tensioner was reinstalled the relationship of the cams shifted a tad. Perhaps my chain is reaching the end of its life. I was able to get the tension perfect and the marks correctly aligned at the second attempt. Hopefully I will have the knack better next time. The proof of the pudding is that it started easily :)

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