Please Help! Putting intake/exhaust cams back on

[kaijetucker]

Replaced head gasket. reassembled to the point that I need to put cams back on. Having trouble. Here's the run down:

1. It is an '81 gs 750
2. cams shafts and chains are all original/correct parts
3. trying to put cams on, but there is *barely* not enough slack in chain to fit around the teeth of the cam shafts while they are in their seated position
4. cannot move chain back/forth with hand
5. are you supposed to be able to turn the chain by hand?
6. is it possible that the chain is stuck?
7. if so, is it possible that there may be something like a washer down in there? I don't remember dropping a washer, but is something like that common?

[Steve]

You have the tensioner removed?

You have both cams removed?

You have the spark plugs removed?

You have the ignition cover on the right end of the crank removed?

Assuming those four conditions, you should be able to use your hand to tansion the chain and turn the crank to ensure it is not bound up on the lower sprocket. It is then possible to watch #4 piston come to the top, verify the exact timing at the marks on the crank, then install the exhaust cam, holding tension on the front of the cam chain to make sure it is straight. When the exhaust cam is in place, install the intake cam, making sure you count the proper number of pins between the marks on the cams. When the intake is bolted in, install the tensioner. Be sure to release the plunger, then adjust the set screw properly and lock it in place. Finally, turn the crank slowly for two full turns CLOCKWISE to make sure that nothing is hitting.

Where are you? Nothing in your profile that hints at location. Someone might be close enough to lend a hand.

.

[kaijetucker]

I'm in the Omaha, NE area. Papillion, actually.

Ok, I met the conditions you gave, as far as what should be removed. There was no movement in the chain and no slack whatsoever to fit the intake cam on. Do you think the chain is bound up? Should I take the engine block back off to look inside?

[Nessism]

Try holding up the cam chain with your hand while turning over the engine with a wrench. The chain is most likely bound up a little on the crank sprocket and that should free it up. That's a good sanity check anyway to make sure you got the pistons and rings installed anyway.

[Steve]

Should I take the engine block back off to look inside?

Probably no need to disassemble the engine. Hold the chain up with one hand, try moving the crank in both directions with the other hand. Chain might be bound around the sprocket, rocking the crank might set it free.

.

[kaijetucker]

I'm sorry for the stupid question, but how do I turn it over with a wrench?

[Nessism]

I'm sorry for the stupid question, but how do I turn it over with a wrench?

There is a 19mm hex under the ignition cover, on the RH side of the engine. You know to align the crank at 1-4 T before installing the cams right? Do you have a service manual for your bike? It's all in there. In case you don't have a manual you can download one for free here...http://members.dslextreme.com/users/bikecliff/

[kaijetucker]

Oh yeah, sorry. I have been following the manual, but I did not need to remove the cylinder block or the ignition cover. I'm going to try to locate it. Currently I have the cylinder block AND cylinder head on the bike. I was trying to put the cams in, and there was not enough slack to fit around both, and the chain would not move.

[Nessism]

Oh yeah, sorry. I have been following the manual, but I did not need to remove the cylinder block or the ignition cover. I'm going to try to locate it. Currently I have the cylinder block AND cylinder head on the bike. I was trying to put the cams in, and there was not enough slack to fit around both, and the chain would not move.

Well, you can't time the cams without removing the ignition cover since the alignment marks under under there. Sounds like someone needs to slow down and READ the manual completely before going any further.

[kaijetucker]

Okay, I went to the reassembly portion of the manual and got it figured out, except the actual initial problem, which is there is simply not enough slack to put the chain around both cams.

[kaijetucker]

so, is there any kind of typical problems where there is not enough slack to engage both cams in seated position?

[loud et]

Go to bikecliff site and download the manual. Step by step instructions with pictures. Easy easy....take your time, relax, so you don't break anything. Manual covers it all.

[Nessism]

Did you do as Steve and I suggested? Hold up cam chain while rotating the crank? Can you spin the crank a full turn while holding the chain up?

[7981GS]

so, is there any kind of typical problems where there is not enough slack to engage both cams in seated position?

As they probably mentioned, you can hold the chain up with one hand while turning the crankshaft back and forth to relieve the knot of chain that you must have at the crankshaft that is not giving you the slack that you need.
Take a flashlight and shine it down through the frame backbone and you can see the knot of chain.

Eric

[kaijetucker]

Okay, figured it all out. I had cranked it by hand, set the timing as suggested in the manual (I own a paper copy of it) and followed all suggestions step-by-step. The problem (wasn't mentioned in the manual) was the the tensioner was stuck, and once I got it un-stuck, it needed to be adjusted. I loosened a bit until I could fit the cams in, then re-adjusted.

Sorry for any confusion, guys.