Topic: CB400 Trouble fitting Cam

[Lynx]

Hi all,
I'm in the final throws of my CB400F engine rebuild but I'm now stuck. My manual says put the can sprocket in the chain then feed the cam through it from the right side. I tried this but I now have the cam wedged in half way. I can't move it either direction  . Am I going about this wrong or in my chain too short? It's a DID bought from M&P. Any advise gratefully received. I DO NOT WANT TO STRIP IT DOWN AGAIN  .

[oldbob]

First off, try to back the cam shaft out of its current position. You put it there, so it must be possible to get it back out.

As far as I remember, I slipped the cam shaft through the sprocket and "seated" the cam shaft *before* placing the chain on the sprocket. Then (and only then) did I bolt the sprocket to the cam.

Bob

[thrutheframe]

Make sure your cam chain tensioner is backed off all the way and unbolt the sprocket from the chain.   Figure out a way to clamp the sprocket to the cam so the force is paralell to the length of the cam.  That will keep excess strain off of the parts as you back the bolts out.  When you release the clamps do so slowly and evenly.  Sorry I cant be more specific but I've never seen a 400F cam.  If it's not possible to use the clamps just back the bolts out equally 1/4 - 1/2 turn at a time in a x pattern if there are 4.

+1 on what Bob said about putting the chain on the sprocket last.

[Lynx]

Done it! Thanks. The hard part was getting the sprocket off the cam, but with the wife's help, a large screwdriver as a lever and a hammer, got it to go back over the cam lobe. I re-fitted it as about. Quite fiddly but it worked and is in place and timed correctly  . What a relief. It was looking like I have to split the chain and fit a soft link for a while.

[oldbob]

Let me re-phrase what I wrote. With the cam in place (and through the unbolted sprocket), position the chain on the sprocket. Make absolutely certain that the lines on the sprocket align with the corresponding surface on the cylinder head while the crank shaft is at TDC. To get everything into position, you will almost certainly have to reposition the chain on the sprocket. Once the parts are correctly positioned, bolt the sprocket to the cam. (You will probably have to rotate the cam; not a big deal.

Bob