Topic: Cb750 clutch problem

[Mbg1247]

Hey guys,this my first post and I'm a definite newb to old bikes. I have a 72 cb750k recently brought back to life. I was cruising the other day and lost all my gears. Heard a lot of clanking and turns out my clutch cover blew apart where the actuator is. Nothing fancy done to bike, drag pipes and jetted. Any reason the clutch cover would do this? I'm gonna order a new cover but I don't want this to happen again. Thanks in advance.

[Mbg1247]

Here is a picture of the aftermath

[HondaMan]

My guess: someone before you has installed too-strong clutch springs (and maybe improperly as well). Find some good used Honda clutch springs for the CB750 K0-K5 bike and install those instead, when you install your new cover.

The original clutch and springs for the K2 can handle nearly 90 HP. There is absolutely no reason to install stronger springs or "better" clutch plates in that engine. All that usually does today is cause problems from incorrect and marginal aftermarket clutch parts.

I fix a LOT of 750s that have gone through this, so I'll call this my 5 cents' worth...   

[scottly]

Pull the clutch cover off and take a picture, please.

[Mbg1247]

Thank you , Hondaman. Scotty, I will upload a pic tomorrow after I get the cover off. It's late and I'm in bed

[HondaMan]

Thank you , Hondaman. Scotty, I will upload a pic tomorrow after I get the cover off. It's late and I'm in bed

I understand. I used to sleep next to my 750, too.

[Lost and Confused]

Recently I replaced my clutch as part of rebuild. When starting from a stop, had a noise like grinding. I had put Barnett springs in. So I took it apart and replaced the springs with Honda springs. Problem solved. I wish I had known about using stronger springs in these bikes. Thanks  Hondaman.




Bob

[Mbg1247]

Here's a pic with the cover off...



I think I know what happened. The nut that holds the clutch pack together backed off, probably explains lack of any forward gears. Springs, age, and abuse probably account for the cover breaking the way it did. It was originally my fathers bike, bought it brand new in '72 when he was 18 and I know for a fact that thing was rode hard and put away wet.

[Mbg1247]

In other news, with a broken down bike it gave me time to work on my yard...

[HondaMan]

Here's a pic with the cover off...



I think I know what happened. The nut that holds the clutch pack together backed off, probably explains lack of any forward gears. Springs, age, and abuse probably account for the cover breaking the way it did. It was originally my fathers bike, bought it brand new in '72 when he was 18 and I know for a fact that thing was rode hard and put away wet.

The bolts holding the spring plate down are not OEM, nor are those clutch plates. It looks like the plates were changed and the nut not cinched back in place, then?

[Mbg1247]

Is the nut supposed to be staked? The threads on the nut were mostly torn out, i definitely have to get a new nut. The clutch plates arent anything special other than a stock replacement. I just hope that new springs, new nut, and new clutch cover plate will take care of it. I cant wait to get some winter riding in  . Best part about riding in the winter... There is no winterizing necessary!

[HondaMan]

Is the nut supposed to be staked? The threads on the nut were mostly torn out, i definitely have to get a new nut. The clutch plates arent anything special other than a stock replacement. I just hope that new springs, new nut, and new clutch cover plate will take care of it. I cant wait to get some winter riding in  . Best part about riding in the winter... There is no winterizing necessary!

The nut is still available, so is the staking plate. I just bought 6 of each last Spring for the engines I have here.