Author Topic: Parts catalog drawing question for 1976 cb750f (Read 3713 times)

oldskullero · « **on:** April 12, 2016, 05:17:44 AM »

Hi guys, just an update referring to the shifting problem i have. Had it opened today and i found 8 clutch discs inside. Which i wanted to replace all just so that everything will be all fresh. But the thing that stops me from getting the parts is that there is something that i need to know about the part identified in the drawing with a no 5 and 6 is underneath it. Is this for my engine or another engine model perhaps? The counting also does not indicate. Its actually blank. Anybody can help clear this out?

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70CB750 · « **Reply #1 on:** April 12, 2016, 05:25:00 AM »

Some clutches have a double steel disc in the middle of the pack. The number of plates changed some over the time. My K0 had just plates, while the 78 CB750F had the dual disc in the middle.

flybox1 · « **Reply #2 on:** April 12, 2016, 06:33:29 AM »

+1 the '6' is the double thick steel plate.
You'll have to pull your plates to see what you have.
As long as they are not warped, all steel plates can be cleaned and reused.
You probably only need to buy new cork plates.

oldskullero · « **Reply #3 on:** April 12, 2016, 07:37:20 AM »

Hmmmm. Ayt then. Ill take note of that.

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Jerry Rxman Griffin aka MuthaF'er · « **Reply #4 on:** April 12, 2016, 07:42:43 AM »

Only the final few 76's upgraded to the double disc. It requires either a later/longer basket or the removal of one disc as the field upgrade for a noisy clutch.

oldskullero · « **Reply #5 on:** April 12, 2016, 08:24:05 AM »

And this is what i found out. I saw a total of 8 disc. That makes sense 6 plus 2. Quite confused at first thats why i asked. Ill post some photos tomorrow guys.

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oldskullero · « **Reply #6 on:** April 12, 2016, 08:26:04 AM »

Quote from: Jerry Rxman Griffin aka MuthaF'er on April 12, 2016, 07:42:43 AM

Only the final few 76's upgraded to the double disc. It requires either a later/longer basket or the removal of one disc as the field upgrade for a noisy clutch.

Im interested on this bro. Can you explain further about this one?

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Jerry Rxman Griffin aka MuthaF'er · « **Reply #7 on:** April 12, 2016, 06:26:48 PM »

Honda issued a Field Fix Service Bulletin dated 12/8/1976 "CB750 Clutch Noise Update". It's posted up here somewhere. They came up with 'the fix' in response to the noisy clutches. They took a 75 - 79 ?? GL double metal plate and added it to the middle of the clutch pack in place of 1 stock metal plate, the 4th from the bottom of the stack, and removed one fiber plate, the one from the bottom of the stack, to make room. The 'permanent' fix in late '76 was to make a slightly longer basket to accommodate all the fibers AND the double metal disc. You can swap out all the parts. Works nicely. It gives you 2 options for a noisy clutch or you can keep the original set up. If you go with using a 77/78 clutch set up you also need to get a 77/78 clutch cover or modify your stock one by grinding down the inner ridges.

oldskullero · « **Reply #8 on:** April 13, 2016, 04:51:03 AM »

Hi guys. These are the clutch discs i found. There is a total of 8. How could this be?

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oldskullero · « **Reply #9 on:** April 13, 2016, 04:52:28 AM »

Can somebody enlighten me why there are 8 friction discs inside?

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70CB750 · « **Reply #10 on:** April 13, 2016, 05:28:37 AM »

My collection of service bulletins, not sure if the clutch is in there.

https://sohc4-forum-attachments.s3.amazonaws.com/honda_cb750_service_bulletins.pdf

oldskullero · « **Reply #11 on:** April 13, 2016, 06:07:01 AM »

Thanks @ 70Cb750. I tried to check it but the clutch disc issue didnt appear to be in those service bulletins but still big thanks. @ Jerry Rxman Griffin aka MuthaF'er . Can you check the clutch disc photos i posted.

madmtnmotors · « **Reply #12 on:** April 13, 2016, 06:25:22 AM »

Quote from: oldskullero on April 13, 2016, 06:07:01 AM

Can you check the clutch disc photos i posted.

Not sure how you got eight friction disks, unless someone installed an aftermarket "extra disk" clutch pack. Did you take pictures, or at least some notes, about the order of the steel plates in relation to the friction plates? You will have to measure the thickness of the steel plates as well as the thickness of the friction plates to try and determine what you are working with. How many steel plates were in your clutch pack?

flybox1 · « **Reply #13 on:** April 13, 2016, 07:51:20 AM »

Quote from: oldskullero on April 13, 2016, 04:52:28 AM

Can somebody enlighten me why there are 8 friction discs inside?

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One is not like the rest

madmtnmotors · « **Reply #14 on:** April 13, 2016, 09:24:56 AM »

Quote from: flybox1 on April 13, 2016, 07:51:20 AM

One is not like the rest

That is true, the later style uses a slash cut friction on the outermost location. The later style still only uses seven frictions, including the outer slash cut one...

Jerry Rxman Griffin aka MuthaF'er · « **Reply #15 on:** April 13, 2016, 10:56:57 AM »

I do believe that the one outer most plate B would have larger tabs. Can't tell, are your tabs all the same size?

8 = aftermarket

later basket is slightly longer

oldskullero · « **Reply #16 on:** April 13, 2016, 04:32:39 PM »

Well that explains it. Another kudos for jerry. I also would like to thank hondaman for his very informative story on how things have happened during those years regarding the clutch issue. I was hoping then to ask you guys to post the part nos ill be looking for these. I believe the best approach is to buy the whole sets and replace them all to rectify the problem.

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madmtnmotors · « **Reply #17 on:** April 13, 2016, 04:43:17 PM »

Quote from: oldskullero on April 13, 2016, 04:32:39 PM

Well that explains it.

Explains what?

You still don't know what you have. You have to measure the thickness of the friction disks and the thickness of the steels to know for sure. The aftermarket "extra disk" clutch packs have thinner disks (both steel and friction). If your steel and friction disks are the same thicknesses as stock, then some goob put too many stock friction disks in your stack...

oldskullero · « **Reply #18 on:** April 13, 2016, 05:16:48 PM »

That explains the problem i had before why it doesnt shift properly coz the combinations inside are wrong. The bulletin explains it. And correct i should measure the thickness first.

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madmtnmotors · « **Reply #19 on:** April 13, 2016, 05:28:25 PM »

Quote from: oldskullero on April 13, 2016, 05:16:48 PM

That explains the problem i had before why it doesnt shift properly coz the combinations inside are wrong.

Okay, we're all on the same page then. If the components you have are stock, and if they are within spec, then it may just be a matter of assembling them properly (i.e. only seven friction disks). How many steel disks were in the stack?

oldskullero · « **Reply #20 on:** April 13, 2016, 05:49:26 PM »

@madmtnmotors > 7 steel plates as well

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madmtnmotors · « **Reply #21 on:** April 13, 2016, 05:55:32 PM »

Quote from: oldskullero on April 13, 2016, 05:49:26 PM

@madmtnmotors > 7 steel plates as well

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So now we just need to know the thicknesses to determine whether you've got the "extra plate" aftermarket, or an over enthusiastic previous owner that just kept stacking stock plates. Since you also have an extra steel plate (there should only be six plates if they were stock), it's likely that you do indeed have the "extra plate" aftermarket clutch.

Was one of the steel plates the double thick riveted plate (clutch plate "B" in the diagram posted by Jerry)?

oldskullero · « **Reply #22 on:** April 13, 2016, 06:02:22 PM »

Nope i didnt see that. Thats whybi was wondering. It was all identical.

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madmtnmotors · « **Reply #23 on:** April 13, 2016, 06:09:34 PM »

It could be one or the other:

>It could be the early style stock setup, with too many plates (one extra steel and one extra friction), but this seems more and more unlikely, since I'm not sure you could cram that many stock plates in the basket (but I've been wrong before!)
>Or you do indeed have the extra plate aftermarket setup. Measuring the plates thicknesses will tell for sure.

oldskullero · « **Reply #24 on:** April 13, 2016, 06:12:10 PM »

Maybe ill have to go for the service bulletin setup. Its the best way to go.

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Author Topic: Parts catalog drawing question for 1976 cb750f (Read 3713 times)