Topic: CB750 Clutch spline 25mm washers - different for different model baskets??

[Ace]

I've pulled apart some clutches and never too much notice until I was putting a clutch together tonight.  I know there are differences in clutch baskets for early and later model bikes, hub lengths etc. While I was putting together a K2 with a late model clutch basket in it I noticed that I couldn't find the usual thick spline washer.  The only washer I had was a small one that looked like out of the transmission assembly. I pulled it apart 2 months ago and didn't take much notice. Pictures are below of the two in question. The K2 engine has the F2 later model basket and the F2 spline washer.  Is this how it's supposed to be with the later clutches? I noticed that I couldn't fit the thicker K2 washer and turn it into the groove (if you know what I'm trying to talk about).

[Ace]

Thinking about it a bit more and I have also noticed that the difference between washers is probably directly related to the primary drive shaft.  My K1 doesn't have a groove to put a circlip in that holds the clutch basket in, where as the primary drive shaft in the engine I'm putting together does. Since it has been apart before, if they changed the primary drive unit they probably also put in a late model clutch. By doing this you would have to change the spline washers out to ensure correct fitment. More subtle differences with clutch setups.

[scharny61]

Hi Ace
did you resolve this issue? I have a K6 engine with a K2 basket I think and need help sorting it out. Were the shafts different between the K2 and the k6?
cheers

[Ace]

Hi Ace
did you resolve this issue? I have a K6 engine with a K2 basket I think and need help sorting it out. Were the shafts different between the K2 and the k6?
cheers

G'day Scharny61, the setup is now back to early model basket. I haven't taken it for a ride a I pulled the head off to fix an oil leak and was 2 orings short in putting the head back on.

I've since found out that the shaft that the clutch basket fits on which goes into the primary drive are different throughout the models. The larger washer fits on the shaft that doesn't have a groove cut out of the outer end for a circlip to fit on to hold the clutch basket on. The later models shafts have this circlip groove and use the smaller washer to make it all space out correctly (I think anyway).

As soon as I've got the bike back on the road I'll let you know. Hope this helps. I don't have any picks either, I'd have to google for pics.

Catcha.

[scharny61]

Thanks ace, always learning eh? Will be interested in the outcome.

[Jerry Rxman Griffin aka MuthaF'er]

Later style



The smaller 25mm spline washer fits INSIDE behind the splines while the earlier larger 25mm spline washer fits outside

[Ace]

Later style



The smaller 25mm spline washer fits INSIDE behind the splines while the earlier larger 25mm spline washer fits outside

Yep there you go, pictures make it easier. Thanks Jerry.

[scharny61]

Thanks Jerry, good pic. Is it unusual to have a non circlipable shaft in a motor that is a k6? do you happen to know which models had the shorter springs? These clutches seem to be all over the place.

[PeWe]

I had similar thoughts when I had my K6 clutch apart and putting it together. It took too long time until I put it together so I was not sure about the washer. (Maybe something lost in the garage...)
I used the parts charts at CMSNL for my model... looked at US model too.

One important detail is that US K6 and European K6 has different clutches. The EU -K6 version has not the double metal plate and therefore different hub.

[Jerry Rxman Griffin aka MuthaF'er]

The US did not go to the double plate either until very late in the 76 F1 model and it did not go into the K until the K7 model from best that I can research.

[andrewk]

Not too many things surprise me anymore with these bikes.  35 years is the youngest of the breed,  anything can happen in that time, lots of things get changed along the way,  stories not excluded.  Is the engine serial verified as a k6?

Honda made a ton of little changes to combat clutch rattles.  You would have to find the service bulletins to get an exact serial number break, but these changes were rolling production changes, so if your k6 is late enough, it might have been stock, or might have been a service update, etc.

[Jerry Rxman Griffin aka MuthaF'er]

I posted the Honda service bulletin (The Wrench) in another thread. That is where my information is from. Beginning serial numbers for the double GL1000 Clutch Plate B p/n 22322-371-313 are: CB750 E #2700014 and CB750F E #2557523.