Topic: Cam chain noise after adjustment

[xxHillratxx]

Hi there all,

I tried the search function and have read about cam chain adjustment on this forum and decided to do the easiest method of starting the bike and releasing the set bolt on the tensionor and then re tightening. Now I have more valve train noise than I did before the adjustment. Is this normal or does the tensionor make noise when its doing its job?

Thanks for the help

 

[70CB750]

What bike?

[nccb]

you need to set it while the bike is off.  Take the #1 tappet cover off and your points cover.  Rotate that plate until it is 15 degrees past the T mark for the 1-4.  Check to make sure the number 1 valve is open and then undo the tensioner screws.  Tighten it up and you should be good to go.

[xxHillratxx]

Sorry. 1974 CB750k.
Ive read that both methods are acceptable.

[nccb]

now that you have tried it that way.  Try it the static way and see which is best.  I have also read to put a bit of pressure on the kickstart when you tighten it back up.

Also, if you use the google search on this there have been numerous conversations about how Honda changed the procedure in the later years, I forget the speculation as to why but I think the consensus is to do it the way I described from the older manual.

[Black 750K8]

now that you have tried it that way.  Try it the static way and see which is best.  I have also read to put a bit of pressure on the kickstart when you tighten it back up.

Also, if you use the google search on this there have been numerous conversations about how Honda changed the procedure in the later years, I forget the speculation as to why but I think the consensus is to do it the way I described from the older manual.

You are correct. Mostly with the plugs out. The engine in this position wants to roll back and light pressure will prevent this. A socket on the big nut at the points and ratchet with the handle pointing at the front tire is all you need.

[xxHillratxx]

Thanks for the tip with the kick start. I did just try the static method and it seemed to solve the noise for about a minute. As soon as I started riding It started clattering away again. I'll try the kickstart hold method next attempt and see how that goes.

[ekpent]

In some more rare instances,especially if the bike has been sitting a long time the adjustment rod can have a light seize and will not move, a tap with a punch may help. On new to me bikes I usually remove the tensioner and clean to check while the carbs are off..
  Another issue can be when people crank the bolt down too hard it can create a dimple on the  adjustment ramp of the tensioner so when the bolt is re tightened the ramp simply slips back into the old dimple location. Never adjusts to the "new" location. The cure for that is to dress the ramp to removed the dimple.
  Other parts like rollers etc get old also and yours just may run a little more noisy.

[MCRider]

All that ^^^

To see if the plunger is not moving freely, with the engine turned off, and the lock bolt loose, insert the short end of an Allen wrench in the hole at the rear of the tensioner. Move the engine forward and rearward with the ignition nut.

The plunger should react to the chain getting tight and loose, pushing the wrench in your hand in and out.

[xxHillratxx]

Ekpent and MCrider: that makes alot of sense. Thanks. I will rip the tensioner off this eve and inspect. Will it come off with the carbs installed?

[katman]

I am putting my 77 750K back toghether after a frame down restore. Do you need to use the timing marks set at the correct position then add pressure
to the kick start lever.

[lucky]

Hi there all,

I tried the search function and have read about cam chain adjustment on this forum and decided to do the easiest method of starting the bike and releasing the set bolt on the tensionor and then re tightening. Now I have more valve train noise than I did before the adjustment. Is this normal or does the tensionor make noise when its doing its job?

Thanks for the help

I cannot believe you would take a chance or ruining your engine to do this procedure with no instructions from the manual.


Thinning of the herd I guess.

[katman]

Who said anything about not using the manual. What I am saying is setting the marks were they are supposed to be with 1 exh fully open.
I have read and been told from a 750 mechanic that putting pressure on the kick lever takes the slack out of the front of the chain.

[MCRider]

I am putting my 77 750K back toghether after a frame down restore. Do you need to use the timing marks set at the correct position then add pressure
to the kick start lever.

My understanding is that if you set the crank at 15deeg ATDC (left side of spring post) putting pressure on the KS is unnecessary. At that position the valve springs are very taught and turning the engine forward with the 17mm Ig nut, is all that's necessary.

[xxHillratxx]

Well Lucky, as stated, I did research on this forum and read both methods for setting the tensioner. From what I have read, the Clymer says to use the static method and the Honda shop manual says to use the dynamic. I'm not an idiot and I dont need to be thinned from the herd.

As for everyone else, thanks you for the input. I have tried both methods now including disassembly and inspection of the tensioner. The tensioner is moving smoothly and is not indexed from an overtightened set bolt. I am thinking perhaps the noise I am hearing is not cam chain related.

The noise is definately more prominent when I lean the bike to the right and subsides a bit when I lean it to the left. It is a tick/knock/clatter that follows engine rpm. Ill try to upload an example video this eve.

[nccb]

you might have done this already, but have you adjusted your valves and synched your carbs?  They can make some similar noises if you aren't used to hearing something like that.

[krusty]

Have you checked the primary chains?

[MCRider]

Well Lucky, as stated, I did research on this forum and read both methods for setting the tensioner. From what I have read, the Clymer says to use the static method and the Honda shop manual says to use the dynamic. I'm not an idiot and I dont need to be thinned from the herd.

As for everyone else, thanks you for the input. I have tried both methods now including disassembly and inspection of the tensioner. The tensioner is moving smoothly and is not indexed from an overtightened set bolt. I am thinking perhaps the noise I am hearing is not cam chain related.

The noise is definately more prominent when I lean the bike to the right and subsides a bit when I lean it to the left. It is a tick/knock/clatter that follows engine rpm. Ill try to upload an example video this eve.

Does the noise go away when you pull in the clutch lever?

[lucky]

Well Lucky, as stated, I did research on this forum and read both methods for setting the tensioner. From what I have read, the Clymer says to use the static method and the Honda shop manual says to use the dynamic. I'm not an idiot and I dont need to be thinned from the herd.

As for everyone else, thanks you for the input. I have tried both methods now including disassembly and inspection of the tensioner. The tensioner is moving smoothly and is not indexed from an overtightened set bolt. I am thinking perhaps the noise I am hearing is not cam chain related.

The noise is definately more prominent when I lean the bike to the right and subsides a bit when I lean it to the left. It is a tick/knock/clatter that follows engine rpm. Ill try to upload an example video this eve.

The Honda CB750 cam chain slack is taken out by adjustment when the engine is OFF. NOT when it is running. Some Honda cam chains ARE checked when running, but NOT the CB750.

You did not tell us how many miles are on this engine. The cam chain rollers could be dried up broken rubber bits circulating all through the oil system and that includes the crank oil journals. 40 years old cam chain rollers.

Did you check the sump screen?


Quote:
"I tried the search function and have read about cam chain adjustment on this forum and decided to do the easiest method of starting the bike and releasing the set bolt on the tensionor and then re tightening. Now I have more valve train noise than I did before the adjustment."

You will be lucky if the cam chain did not slip a tooth. I hope not.

[lucky]

Sorry. 1974 CB750k.
Ive read that both methods are acceptable.

Where did you read that?
Was it a forum member?

Do not trust that information. Check the book again.

[78whiteorbs]

Lucky, I also have read that the manuals states to do it with the engine running. I think there have been a few threads on this topic. Seems the old manuals stated to do the static method and the newer ones Honda said to do it running or vice versa I don't recall.

[Viktor.J]

The shop manual does NOT state that the engine should be running. I both read it, I printed it out to a fellow cb750 rider and discussed it with a honda mechanics since 1967. Static and 15 ATDC is the way that's stated in the manual, at least the manual for my bike. The honda mechanics first thougt it could be running but then quickly changed to that this was the later on cb900 and perhaps the DOHC 750(at least what he could recall, he's starting to get old these days).

I just wanted to be clear on that point.

[MCRider]

The shop manual does NOT state that the engine should be running. I both read it, I printed it out to a fellow cb750 rider and discussed it with a honda mechanics since 1967. Static and 15 ATDC is the way that's stated in the manual, at least the manual for my bike. The honda mechanics first thougt it could be running but then quickly changed to that this was the later on cb900 and perhaps the DOHC 750(at least what he could recall, he's starting to get old these days).

I just wanted to be clear on that point.

If the manual you are referring to is for your K2, that's the point. The earlier manuals, pre K7, had the static method. The later ones had the running method.

I was in a cam chain thread a few years ago where a copy of the pages of the K7/K8 manual was posted and sure enough, it very clearly stated to adjust with the engine running. And it was referring to the CB750, no mistake.

Nothing had changed in the design of the parts, so I still maintain that the static method is better.

But people stating they read the running method in a CB750SOHC manual are not crazy, they read it. AS have I.

PS: And in that thread several people stated they did it while running and got an acceptable result.

[Viktor.J]

The shop manual does NOT state that the engine should be running. I both read it, I printed it out to a fellow cb750 rider and discussed it with a honda mechanics since 1967. Static and 15 ATDC is the way that's stated in the manual, at least the manual for my bike. The honda mechanics first thougt it could be running but then quickly changed to that this was the later on cb900 and perhaps the DOHC 750(at least what he could recall, he's starting to get old these days).

I just wanted to be clear on that point.

If the manual you are referring to is for your K2, that's the point. The earlier manuals, pre K7, had the static method. The later ones had the running method.

I was in a cam chain thread a few years ago where a copy of the pages of the K7/K8 manual was posted and sure enough, it very clearly stated to adjust with the engine running. And it was referring to the CB750, no mistake.

Nothing had changed in the design of the parts, so I still maintain that the static method is better.

But people stating they read the running method in a CB750SOHC manual are not crazy, they read it. AS have I.

PS: And in that thread several people stated they did it while running and got an acceptable result.

That's my point, make sure its the correct manual for your bike. And K7/K8 are nearly ( hahah) a DOHC so that doesn't count.

And regarding that some get accepteble resaults with dynamic method, Two wrongs doesn't make a right

[Dream750]

The CB750 engine running adjustment procedure first appears with the 1977 750 K7. For whatever reason, Honda never published a shop manual supplement showing that a running adjustment was to be used on the K0 to K6 models. The static method that I have was last updated in the K1 to K4 supplement – pictured below.

Is there a newer shop or owners manual reference published by Honda that shows a running adjustment procedure for the K0 to K6 models? If so, I would like to see it.

Until then, I’ll stick with the static method.