So I'm finishing up intalling a new cylinder head on my cbr1000f and I can't quite get the valve timing right. I have the in and ex marks on the cam sprockets lining up together at the cylinder head, but I cannot get them to line up when the crank and chain is at "T". Instead they line up at the F mark on the crank. If I move it one tooth back, it goes to far.

What am I doing wrong? Will the bike run with the valves timed slightly advanced?

 

There are 'How Too's' on here that may help, take a look in the relevant section at the top of the ''Hurricane'' page.

I seem to remember that the markings only line up every second rotation?

I wouldn't try running it unless everything is lined up perfectly, otherwise you could smash the valves up pretty bad!

Haven't done this job myself so wait untill you get replies from the more knowlegable ones

Found the thread I was thinking of, take a look at this it should help.

https://cbrforum.com/forum/how-tos-81/cam-chain-tensioner-replacement-103362/









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Oh rest assured I have read the howtos with careful attention to detail. They have been very helpful. But neither the cam chain tensioner replacement guide nor the valve clearance guide address my issue. They and the Honda manuals all say just line the sprockets up at the t mark.

However, if I spin the engine in reverse slightly, the sprockets do line up at t. How can this be?

 

If you are rotating backwards and they line up, I would say that you are one tooth off.

Rotate the engine CCW and line up the crank to the T-mark. Next make sure that the EX cam is not off by rotating the cam chain CW with just enough hand pressure to take the slack out of the chain.

Here is where I ran into trouble. Every time I install the IN cam it fell one tooth off. I had to rotate it one tooth off before slipping it into the cam keepers. The "T" mark and the EX valve must be monitored while installing the IN cam.

The final check is to rotate the engine CCW slowly and carefully 2 rotations and check again with tention on the cam chain pulling the cams in proper rotation. Hawkwind is correct, the cams rotate 1/2 the revolutions of the crank so you need to go around twice for final checking.