Topic: 750 Cam Chain Tensioner Adjust Procedure Confusion

[Rosinante]

In looking for the precise "static" (engine not running) procedure, and recalling there is a specific crank/cam position to use, I came across this thread:

http://forums.sohc4.net/index.php/topic,90776.0.html

In this thread, several people INSISTED that the Honda factory K8 manual says to adjust the cam tensioner with the engine idling.  Others said the factory for earlier models also say this.  Running an engine with the tensioner bolt loosened sounds to me like a good way to bend valves.  One person said he used this method and the engine made a rattling noise.  Then he used the static method and the engine quieted down.

So.....is this done with the engine running?  Or is it done static?  At 15 degrees ATDC #1?  If it is done at 15 degrees ATDC, then what exactly is the timing mark pointed to in the little window of the ignition timing plate?

[Tim2005]

I've always done it static, and yes just after TDC where there's a little post visible through the window, whether it is exactly 15 degrees I don't know. Basically I just wind the crank to there & keep pressure on the spanner while undoing & tightening the tensioner. I always do it with the engine hot too. This seems to work for me, my 750 is on around 160000 miles now.

[Rosinante]

Thanks Tim.  That is pretty helpful.  The pressure on the spanner thing, and the temperature.

[newday777]

Yes back in the 70s I learned from the guys out back to do it static when I was learning from them how to work on my own 750.
I didn't hear anything about idling until it was brought up in threads on here. That never made any sense to me.

[ekpent]

In the pictures in a manual they show a post where a spring attaches being in a certain position to set it with #1 rockers loose at least on pre 77-78.

[denward17]

Thanks Tim.  That is pretty helpful.  The pressure on the spanner thing, and the temperature.

What is meant by spanner?

[Tracksnblades1]

In looking for the precise "static" (engine not running) procedure, and recalling there is a specific crank/cam position to use, I came across this thread:

http://forums.sohc4.net/index.php/topic,90776.0.html

In this thread, several people INSISTED that the Honda factory K8 manual says to adjust the cam tensioner with the engine idling.  Others said the factory for earlier models also say this.  Running an engine with the tensioner bolt loosened sounds to me like a good way to bend valves.  One person said he used this method and the engine made a rattling noise.  Then he used the static method and the engine quieted down.


So.....is this done with the engine running?  Or is it done static?  At 15 degrees ATDC #1?  If it is done at 15 degrees ATDC, then what exactly is the timing mark pointed to in the little window of the ignition timing plate?

I’ve read somewhere about adjusting the cam chain at a “fast”  idle with the engine at operating temperature (expansion) but can’t provide any documentation. I know I’ve read it and tried it. However, I think it was in the operator’s manual or a Haynes or Clymers service manuals.

 Because:
The attached photos are from the online service manuals here which indicate statically adjusted and is vague about Engine position. The online service supplements don’t seem to redress any changes to the procedure.

Our local Honda Guy (HondaMan is already used here) 😁 required you to: while at operating temperature touch the cam chain tensioner while engine idled at 1500rpms and mentally remember what vibrations were present. Shut engine off remove alternator cover, and while holding slight counterclockwise torque on the alternator nut, let the cam chain lock loose (monitoring any slight inward movement of the adjuster shaft), continue holding slight counterclockwise torque on alternator nut, and retighten lock on cam chain adjuster. Start engine, set @1500rpms,  touch cam chain adjuster to verify it wasn’t vibrating worse than before adjusting the cam chain.

He was worried about over tightening the cam chain, especially when the engine and chain was cold. But he did go through the period where there were a few cam chain guide failures and was privy to all Honda’s service bulletins and updates. Should have bought all his Honda tools when he retired..

[Rosinante]

What is meant by spanner?

A British wrench. 

Yeah, I always thought it was done static.  But the guys in the thread I linked INSISTED the Honda manual says to do it at idle.  Frankly, I'm not sure how that would work.  First, the cam would be bobbling around the proper position instead of holding still and the cam chain would be wobblng around.  So....I think static is the way to go.  And maybe I just guess at where the timing mark is at 15 degrees ATDC.  I think there is a spring post there.  On the plate.

[HondaMan]

If the cam chain is adjusted with the engine running, it will NOT tension the chain.
The original procedure, from the K0 days when the Honda Service reps were the only gospel and before the famous green Honda shop manual apeared, the procedure was:
1. Remove the #4 intake valve tappet cover.
2. Slowly kickstart the engine over until the intake valve start to open, then look in the points plate's port to watch for the spring stud post to appear. This is about 15 degrees past TDC of the #4 cylinder. NOTE: do NOT turn the engine using the large nut near the points: turning it CCW direction even once WILL bend the mounting shaft, which then causes erratic ignition timing until the shaft is straightened again
3. Release the locknut on the can chain tensioner and release the bolt at least 1 full turn, then retighten the bolt, then the locknut. The reason for this order and 1-full-turn instruction is: the tensioner's shaft is tapered wider toward the engine to help prevent the tensioner from pushing the shaft back, out of adjustment again. Loosening it 1 full turn will help ensure it has plenty of space to slide inward and take up the chain slack.

[Tracksnblades1]

What is meant by spanner?

A British wrench. 

Yeah, I always thought it was done static.  But the guys in the thread I linked INSISTED the Honda manual says to do it at idle.  Frankly, I'm not sure how that would work.  First, the cam would be bobbling around the proper position instead of holding still and the cam chain would be wobblng around.  So....I think static is the way to go.  And maybe I just guess at where the timing mark is at 15 degrees ATDC.  I think there is a spring post there.  On the plate.

👍 Just if you could see the chain at a slow idle as she plays that shunka, shuncka, shuncka song 😁…