Topic: cb750 clutch cover question

[Don R]

 Is there a way to ID early and late 750 clutch covers? I'm putting together a pair of early engines and seem to remember a clearance issue or possible visual differences with a late cover on an early engine. I found nothing useful on google search,
 I'm off to study the covers I have, a mongrel mix at best.

[madmtnmotors]

Is there a way to ID early and late 750 clutch covers?

Yes. The later clutch covers were modified to clear the taller stack of clutch plates after the "double plate" was added to the center of the stack on the later models. The biggest visual clue can be seen on the inside of the clutch case cover. Locate the screw bosses where the outer tin cover attaches, specifically the one closest to where the kick starter shaft passes through the clutch cover. This screw boss extends about an extra 1/4" into the case on the earlier models when compared to the later model clutch case covers. This extra 1/4" of material is enough to lock the clutch up solid if an early cover is used on a later engine (ask me how I know...). The good news is that this extra material can be ground away permitting the use of an early cover with the later clutch. Some have said that the webbing on the inside of the early cover that extend out from the center can also interfere, but careful measurement should determine whether or not this would be the case.

This thread has a picture of the later model cover:

http://forums.sohc4.net/index.php?topic=104570.0

Notice the "flat top" on the screw boss near the kick starter shaft opening.

[Jerry Rxman Griffin aka MuthaF'er]

Later should work fine on early as long as it's not the sand cast. Early on later is a no-no without a little grinding of the inside ribs. The later one has the ribs 'indented' (for lack of better description) while the earlier ones are straight/smooth. Post up a picture, it's easy that way.

[madmtnmotors]

Later should work fine on early as long as it's not the sand cast. Early on later is a no-no without a little grinding of the inside ribs. The later one has the ribs 'indented' (for lack of better description) while the earlier ones are straight/smooth. Post up a picture, it's easy that way.

Jerry is correct. Later covers will work on earlier engines (with the exception of the nine hole sandcast), but early covers require some clearancing to use on later engines.

[Don R]

 Actually it is for a sandcast. I made a 10 bolt cover into a 9 bolt cover to make my 2695 engine complete. It looks good but I have concerns about it working right since it was an unknown year cover. That said, it was in a 75 bike and had a 10 bolt cover on it. The PO said it was the best running cb750 he owned and that's saying a lot, I bought 6 from him. They fit, just half of the 10th bolt hole hangs over.
 I'm making another one, I can do better.

[Don R]

https://photos.app.goo.gl/OaqhvKg1TyIdafci1

[HondaMan]

https://photos.app.goo.gl/OaqhvKg1TyIdafci1

Very slick!

[madmtnmotors]

Very resourceful indeed!

[Don R]

 Thanks.