Topic: Looking for info on 750 clutches

[Jerry Rxman Griffin aka MuthaF'er]

I am looking for info on clutch peripherals on 75/76 vs 77/78. Specifically the differences in 2 parts - the clutch adjusting bolts parts 22841-410-000 on the 77/78 and 22841-300-000 on most of the other models AND the Shaft, clutch release 77/78 22820-410 and 22820-300-000.

I suspect the 77/78 parts are longer due to the nature of the upgraded thicker clutch packs??? I have one of these 75/76 on hand but not the 77/78 to compare to.

[Alan F.]

22841-410-000 on the 77/78



22841-300-000 on most of the other models



clutch release 77/78 22820-410-000


22820-300-000


Are these the items? These photos likely won't show you any important differences. I have K3 and K8 parts to measure if that helps.

[Jerry Rxman Griffin aka MuthaF'er]

Yes, those are the parts. Can you measure the K3 and the K8? My feeling is the K8 are shorter maybe? I was also under the impression the actual clutch cover difference(s) was just the inside ribs had been cut down to allow the longer K7/8 basket to fit inside but perhaps there is also a difference (thickness) in the center where all the parts go through.

I do have my original 75 F clutch cover as a spare I can use to visualize but the K8 unit is installed on one of my 2 bikes just not sure which mix and match. My other engine is a K8 so it's likely on that. Too damn many spare parts laying around to use and get me in trouble. LOL. I have already found I had an earlier basket with the later clutch pack installed and it created a binding that caused my kick lever to danve around and make funny noises. I fixed that issue by utilizing a later basket so now I'm moving on to this issue. Process of elimination.

Thanks Alan!!     

[Alan F.]

Ok, without stripping down my K8 tonight, I have the k3 parts in my shop.

But have a look at these first:
K3 from ebay:


78 F:


77 K:


And a 78k:

[Jerry Rxman Griffin aka MuthaF'er]

Do you see any difference other than the interior 5 ribs of the 73 are not "indented" ie are straight from one end to the other?

Are the screw posts on the exterior all the same length? This was mentioned as a possible difference but I can not see why that would be or even matter.

At this point I'm just curious why the different part numbers (other than black paint on the F) of the adjuster bolt and the clutch release shaft that you see on the right picture of the 78 K.

Please don't take anything apart or off your bike.

Thanks Alan

[Alan F.]

I just did a little reading, no mention by anyone that these parts have differences.

http://forums.sohc4.net/index.php/topic,167269.msg1935043.html#msg1935043
http://forums.sohc4.net/index.php/topic,64339.msg708509.html#msg708509
http://forums.sohc4.net/index.php/topic,165655.msg1914038.html#msg1914038

And I just took a look through HM's book, came up empty there too. I'll get measurements asap this week since it's the only way to be sure.

[Alan F.]

This is from the first thread I linked below:

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.

My K8 is coming apart anyway, don't worry about that at all.

[HondaMan]

The ribs on the early covers will hit the pressure plate if used on the K7/8/F2/3. That's why the little ribs are trimmed back on the later covers. If you use them the opposite way, you run out of adjuster length when setting the lifter. The whole clutch sits outboard slightly on the K7/8 F2/3 mainshaft, compared to the earlier engines, because its boss is a slightly different shape (so the spacing changed).

[CaptFatCat]

I'm running a lifter plate and adjustment bolt from a k2 on a k8 without a problem. those peices look identical to me.
The clutch plates and basket is a big difference.

[Alan F.]

According to the 'Related Fitment' section you can scroll down to on Partzilla, the clutch release shaft on a K8 fits K2 among others.
https://www.partzilla.com/product/honda/22820-300-000?ref=05738ee4eed13f6d39d7c647d1f97675966328ee

The 'bolt, clutch adjusting' for 77-78 F and K bikes is a superseding part number 22841-410-000
https://www.partzilla.com/product/honda/22841-410-000?ref=05738ee4eed13f6d39d7c647d1f97675966328ee

The previous 'bolt, clutch adjusting' 22841-300-000 fits all the way from K8 to K1.
https://www.partzilla.com/product/honda/22841-300-000?ref=05738ee4eed13f6d39d7c647d1f97675966328ee

So until measuring them side by side, I'll conclude there are no differences, just a superseding part number.

[Laids]

I just finished rebuilding a K8 and had similar issues with parts from different years getting mixed up. The K8 engine I got only came with outer basket so I was going to use the inner and clutch I had on a K1 that was in the bike. The cover I thought was the K8 has a boss on the back by the kick start shaft that rubbed the cover so I ground it down but was still rubbing. I then noticed that while the K8 uses a circlip the splined washer I was using was from a earlier model and was too big around, the K8 splined washer is narrower and fits inside rather than out, that gave just enough clearance.

[Don R]

 Thanks, this gives me a clue about my 1124 stroker engine's tightness and inability to kick start even with the plugs out and an entirely different kicker mechanism.  I had checked the rotating assembly for runout and drag but the issued developed later during assembly.     

[Jerry Rxman Griffin aka MuthaF'er]

Alan, I'm with you on your research

[PeWe]

I updated my K6 clutch last winter. F2 1978 clutch with double metal disc.
Huge improvement more robust and no rattling.

I prepared the F2 clutch cover to fit. Removed paint and added an additional breather.
My old K6 cover worked fine too, I saw no differences.

It is the earlier, maybe early K2 that has a round boss sticking out.
Photos here where I compare with an old NOS cover I have.
http://forums.sohc4.net/index.php/topic,180468.msg2092617.html#msg2092617

[Kevin D]

11/70 build K1