slipped cam chain

So I am in the process of rebuilding my engine (again, it seems gasket sealant is necessary...) and I am hung up. I got the head back on, but the cam chain came off of the gear on the crank shaft and I don't know how to get it back on there, I really don't want to remove the head again since I sealed the gasket properly and it has been on there long enough to dry so I was wondering if there were any tricks available to get the chain back on that gear. Right now the cam chain just spins freely in my hands so that is how I know it is not on the gear. Thanks in advance for any and all help.

 

You don't have to pull the head again but you may need to remove at least one camshaft sprocket (or camshaft itself) to gain enough slack in the chain to hang it down far enough to capture its sprocket again.

If "fishing for the sprocket" from above alone doesn't work, you could always drop the sump and then get a buddy to help, one from below one from above.

 

Thanks for replying Brian, I still have both camshafts out since I did not want to put them in without having the cam chain hooked below. I do not remember the chain falling off the last time I had the engine apart so I don't know how this happened. If I remove the sump will I be able to hang the chain from above and hook it myself or is it for sure a two man job at that point? Also, the engine is still in frame.

 

try fishing a little more, you'll get it

 

Get a small mirror and a light to see what your doing down in there.

Takes a bit but you'll get it.

 

I’m looking at the book, haven’t been that deep in a XJ yet.

Could the chain be off of the starter idle gear?
Can you see either gear with a good flashlight?

Keep fishing, close your eyes so that “may the force be with you.”
Seriously it’s going to be a touchy feely thing.

ab

 

AB, he's fighting the cam chain, not the primary.

Consensus seems to be you don't have to get as radical as dropping the sump. Dunno, had one head off an OHC multi once and didn't lose the chain. Haven't had the need on the XJs yet (I can tell you it takes three trained hands to drop the head back on a Norton but it has pushrods.)

Good luck, as always...

 

It's off the crankshaft gear for the camchain. Once you give it some slack like when your pulling the head, it will drop down a bit and when you pull it back up it sometimes will go along side of the gear.

 

Now I AM confused, didn't think the 650's had a primary chain.

ab

 

I have done it & it's APITA, you have to remove the rear can chain guide & tentioner, else you will never get the sucker back on.

 

I know you don't want to hear this, ...

But, I think you are going to have to remove the Rear Chain Guide to get the Chain back on the Crank Sprocket.

If I were faced with this dilemma; I'd get somebody to help me.
Pull the Cams for as much slack as you can get.
Pull the Tensioner to let the Rear Chain Guide give you as much room to maneuver as possible.

Have an assistant turn-over the Engine BACKWARDS while you try to get the Chain on the Sprocket ... {like we had to do when the chain came off the sprocket on a bicycle} ... and hope it doesn't bind while being replaced.

There's a Vertical Hex Bolt and Lock Nut below the Tensioner that locks the Rear Guide.
You may need to loosen it to allow the Rear Guide to be loose enough to let the Cam Chain have any room it might need if the Rear Guide stays locked.

 

Sorry; my fault.

It's not a "true" primary chain, but Yamaha calls it that. It goes from the crank to the "jackshaft" that the starter and alternator are on. Primary drive on the shaft-drive bikes is by gears.

The 550s jackshaft chain IS a true primary chain, as it drives the clutch also, and it has an oil-pressure adjusted solid tensioner that doesn't disintegrate.

Side note: The "primary" chain tensioner is the time bomb in every old shaft-drive XJ. If/when it starts to break apart, chunks get stuck in the gear change mechanism and... (It didn't keep me from buying one either.)

 

Alright everyone, thank you very much for the replies and the help. I ended up going to harbor freight and buying a small mirror on a stick and a couple of long pick tools. I hung the mirror above so I could see what i was doing and worked at the chain with one hand while I spun the crankshaft with my other hand, after a while I was able to get them in sync and snagged a chain link with a gear tooth A couple hours later and the bike was put back together. I rode it out to my moms house since I am running out of room in my garage. She just bought a house with a huge basement she doesn't use so I took one of the rooms and made it my workshop. It was nice getting it out there and it will be nice working on it inside there but good lord, 20 miles in 34 degrees at night SUCKS.


Here she is back together along with my new baby.