Topic: Cam Chain sprocket

[Bodain]

Working on Honda 75 CB550. Just had cylinders rebored. Put it all back together. Head is on. Cam is in. Cam sprocket is detached from cam with the cam chain over it. Now it's time to slide the cam sprocket onto the cam and attach with two bolts. Only it won't go. Not  enough slack in the cam chain. It needs to come up about .050 to seat on the cam. There is no tensioner pressure on the chain. This is not the issue.

If the head was not torqued properly this might expain it. Book states about 15 ft. lbs. I'm under this. Very cautious her. Has anyone actully put 15 ft. lbs on without stripping the bolts?

Any ideas on the cam chain. There must be something I'm missing.

[murtceps1]

Sounds like you are having same prob as I.
I think you must be running the chain between the 2 tensioners. It must run OVER the front blade and the rubbing face of the front guide faces forward. As you lower the head onto the barrel fit the guide in with chain running over ( around ) it and then lower the head down making sure the horizontal pins fit into the slot on the top of the barrel and the head.
Also make sure the adjustable tensioner is seated in the cavity just behind the camchain sprocket on the crank. Its easy to miss and have it slide behind therefore not supported at its base. I compressed it and then lowered it into place before the barrel was fully seated so I could get the adjuster bolt through and then tightened the locknut which holds the tensioner retracted. Instal cam from left side and feed chain over ( right side ) of flange so you can lift cam up enough to feed sprocket in position. Drop cam down and feed chain back across flange and onto sprocket. Time cam with crank mark at  " T " mark cyl 1\4 and notch on right side of cam horizontal, forward, centre level with top face of head.. Fit cam sprocket to cam and bolt up. Turn motor a couple of times and recheck marks line up and then you can release locknut on tensioner to tension chain. NB the chain guide has UP marked on it on the block where the pins go through so don't put it in upside down. Hope that helps

[Bodain]

You sir are a man with experience. Experience is everything! You hit it right on the head. I found the problem about 2 hours after posting that message. I had turned the INNER cam chain guide into an outer cam chain guide. It was on the outside of the cam chain taking up all the the slack. I ripped it apart turned the guide around and got it located on the inside.

Amazing how easy it all went together when you do it right.

Thanks for the reply..

[murtceps1]

Glad to be of assistance it nearly drove m around the twist 

[bryanj]

Oh you rotten people giving away the secrets! I used to let the new apprentices struggle for hours with that one!! Still I suppose most youngsters wont ever work on these any more so its OK really

[Bodain]

Actually I struggled with that one for a total of about 10 hours. The problem was time.... The day I took it apart and the day I put it back together were seperated by about 4 weeks....  Too much time between the two makes me forget. <GRIN>

When I put the valve cover back on I had backed all the tappet adjusting bolts all the way out. Then it came time to adjust the valves. I did cylinder no. 4 per the manual instuctions.. It was on TDC... The manual also says now rotate the engine 360 degrees and do cylinder no. 1... In my mind this wasn't necessary, since both 1 and 4 are TDC at the same time. So I adjusted no 1 without turning the engine over. Did the same for 2 and 3... When it came time to start the thing. It clattered bad...and would not run well at all. I just stepped back and thought about it a bit.  As soon as I pulled those tappet covers It was obvious... I had about .200 clearance on a few. Did the entire procedure again and followed the instructions to the letter. Engine clatter gone.
All this after a rebore and new pistons and rings. Sunday was the first day this thing ran reasonably well since I started this project.
That was a good feeling...

[bryanj]

Nothing better than hearing YOUR work start and run. Have fun and dont run it in too gently as you will "glaze" the bores