Topic: I can't get the cam chain over the cam sprocket

[clayherget]

I cannot seem to get enough slack to get the cam chain over the sprocket.  I have had to re position the tensioner and guide and I compressed the tensioner by hand and locked it into place to give me the maximum slack but still can't seem to get the chain over the sprocket.  The last attempt I did not have the top end torqued down simply because I have had to remove the top end four times now for various reasons and I was hoping I could get the chain on then torque it down.  Could that be the problem?  or am I missing something else?

[evinrude7]

it's been a couple years but i recall taking the cam chain tensioner out.  putting the chain on the sprocket and feeding the cam through sort of like a puzzle.  memory is fuzzy though. 

[goodtryer]

It's a very particular process.

See if this helps:
http://forums.sohc4.net/index.php/topic,369.msg57914.html#msg57914

[bryanj]

WHAT BIKE

[clayherget]

77 cb550

[bryanj]

Check you have the cam chain cushion(front of cylinder) fitted correctly. Its a common fault

[clayherget]

I think you are talking about the cam chain guide and yes.  I had it in wrong at first and had to take the head off to readjust it  I looked it over several time so I am pretty sure I have it in right now.  I appreciate the advice here I do feel like I have followed the steps pretty closely.  I am going to give it one more try today so hopefully it will fit.

[Bodi]

It's fiddly work, I assume you have the sprocket loose and shifted over to the smaller diameter cam area? It is not possible to get a chain on or off with the sprocket mounted as far as I know.

[goodtryer]

Think of it like a puzzle. If you're trying to stretch or bend or force it, the pieces are not positioned correctly.

Look very carefully at the picture. In the starting position for installation, sprocket is loosely in place near the center of the cam, slightly offset to the #4 cylinder side. You lift the cam chain and slide the cam into position from the #4 side moving toward #1.

The cam will be able to fully rest in the normal operating position with the chain looped over it and the cam sprocket loose in the smaller diameter groove.

Now lift the chain and place it in position over the sprocket. The sprocket is still in the narrow groove until the chain is in place.

Once the chain rests properly in the teeth of the sprocket, you can then move the sprocket into the final position.

If you find yourself trying to stretch or bend or you start scratching parts together, STOP! Something got out of position.

It's like a puzzle, it fits together easily & logically. It's just not obvious at first.

Once you get the sprocket in place, you might find that you have to "walk" the sprocket one way or the other in order to get the bolt holes and timing marks all lined up.

You can do it!

[clayherget]

It sounds logical and I know what you mean by if you have to force it its not positioned correctly.  I will give another shot this afternoon and hopefully will get it right.

[JLeather]

If you look at the cam sprocket one of the clearance notches around the center is bigger than the others and will let it drop down the farthest.  You wiggle the cam and sprocket together but loose through the chain until it's chain, sprocket, cam (in that order left to right), and turn the sprocket so it's sitting in the deepest notch on the cam next to the spot where it should be bolted down.  There will be JUST enough slack to get it onto the sprocket.  Cam has to be fully seated in position.  Once you've got the chain on the sprocket you will have enough slack you can walk it one tooth at a time forward or back to get the cam timing correct.  Recheck that timing after you release the tensioner before you put the cover back on.  Mine ended up off a tooth after releasing the tension and I had to back the tensioner off and walk the chain a tooth forward.

[kerryb]

I just did this on that bike, jleathers description is very good but, you just keep looking at how the sprocket could sit lower on the cam while making sure the chain isn't hung up on the lower gear.  When it does fit, you say to yourself.   "how come it took so many tries?"   I found it frustrating, intriging, and satisfying when it finally went together only two teeth from where it needed to be.  Don't give up...ever!