Topic: Another cam chain tension help :/

[My73andme]

76 CB750 engine.

So today I tried to quite this noise and I just can’t seem to figure it out. I have read every thread and I have done the 15 degrees past top and have listened and re tightened the chain adjuster bolt. I even took the tensioner off and cleaned it and checked the spring and parts and all seem good so I reinstalled it. Re did the 15 past top and still nosiy

When it’s running and I listen close I am like 99% sure that it’s the cam chain.

I also watched a guy do it on YouTube and he seemed legit.

When I remove the tappet cover and feel for play I have to use two fingers to get the tappet to move. The guy in the video just pushed and one side with one finger and your could hear the click. Maybe that means something?

Also after I go 15 past T my next move is to loosen the adjuster bolt correct (making sure the tappet is moving) once I break that adjuster nuts I should hear the tentioner move into proper placement...is that correct? Anyway it still sounds the same soooooif I am doing it correctly and there still is noise it’s time to remove engine and take a look...? Is that the only other next step?

HELP

[evinrude7]

my guess is you are hearing clutch rattle. 

[My73andme]

Interesting...what makes you say that? How is clutch rattle adjusted? I plan on installing new clutch springs this week. Is there something else to look into while I have it open and replace before sealing it up?

[evinrude7]

the clutch rattle is inherent on these bikes from what i hear and that it's nothing to be concerned with.  i went through this same thing trying to quiet down the motor on my 76.  a lot of the response i received from the forum was that it's just the way the bike is.  also stuff like get your carbs synced.  it helps quiet things down.  i have read that there are fixes for this depending on the year motor you have, that you can add an additional spacer plate to the clutch.  i'm not the expert on this however.  search the forum for that.    since you are opening up the clutch you may want to look into doing the basket modification.  worked great for me.  here's the link.  http://forums.sohc4.net/index.php?topic=78643.0

[My73andme]

Awesome thanks so much. I just read that too I also have been re searching and re reading the forums and it seems like maybe I have dimple that my tensioner keeps slipping into as I remember there being wear in one area of the rod. So I will pull that off and check it more throughly. I also read I can turn the shaft and fell the plunger for proper movement.

I have brand new carbs and exhaust that sound so beautiful and this rattle is just too nosiy. But if that’s the way they are then I will live with it. But I will try most everything before that

What’s the best way to take the dimple out? File? Sand paper? New plunger?

[evinrude7]

i was told file. 

[pjlogue]

What Evenrude7 said; make sure the carbs are synced.  Check your tappet clearances and adjust them before you try and sync the carbs.  Adjust the idle air screws after syncing the carbs for best idle (keep idle at 900-1000 rpm while adjusting the idle air screws)  If you then are getting excess rattles after these adjustments then start looking for the cause.  Some rattles are inherent in the 750 SOHC engine. 

-P.

[My73andme]

Thanks friends 😎