Clutch animal, don't you just hate this....


Clutch animal, don't you just hate this....

Postby CBX1000chris » Fri Feb 14, 2020 8:18 am

Hello all,
I've finished my friends bike (thread - - "Curious engine low compression" -- I've added some pictures of the bike to the thread if anyone is interested, as 'specials' go it's pretty good I think), so I thought I'd crack on with my own bike. The clutch has been typically noisy for a while but has recently developed a noise on operation, if it was an old car you'd suspect the thrust race. I ordered the rubber mounting fit from The Six Center to fit as it seems a popular modification. Anyway, to my absolute horror this is what I discovered when I removed the lifter plate bolts.

7956

The bolts look like 1/4" BSF or UNF, can't be sure but why not at least cut them to the correct length, have you no shame!!!!!

Looking at the manual I can see the bolts are 'specials' and that there are two types. It looks like one of the bolt types is used to centre the lifter plates, am I barking up the wrong tree here? If someone has a lifter plate to hand please can you tell me the diameter of the six mounting holes, mine doesn't look to have been drilled out so may be OK.

My plan then is to see if I can get hold of the correct bolts, and if I can I'll Helicoil the six holes in the basket. This was going to be a 5 minute job.......

Also, how much tension should there be on the leaf spring on the inside of the case? I can almost fully turn the lever on the outside of the case before the arm makes contact with the spring.

Thank you in advance and regards,
Chris.
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Re: Clutch animal, don't you just hate this....

Postby EMS » Fri Feb 14, 2020 9:43 am

The bolts are 6mm and the long ones are 30mm (32mm for the CBX-A), the short ones are 24mm
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Re: Clutch animal, don't you just hate this....

Postby CBX1000chris » Fri Feb 14, 2020 11:36 am

Hi EMS,
Looking at the '79 workshop manual the bolts appear to be 'specials'. I've copied the image below.

7957

In the CMSL parts list several '79 CBX models are listed for the different world markets and all have the clutch bolts listed as item number 17 and 24 on the clutch exploded drawing. The information for 17 is:

BOLT,SPECIAL,6X30
product number: 90008415000

However the information for 24 is confusing, there are many different bolts and screws listed against that number.

I'm very confused.....

Regards,
Chris.
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Re: Clutch animal, don't you just hate this....

Postby Jeff Bennetts » Fri Feb 14, 2020 11:37 am

Here's an old EBay link to a late model complete clutch assembly, click the original item ad button then browse the sellers pictures of the clutch components. You'll see the two special shouldered locating bolts that you referred to, and the two recessed tower bosses that they go into, they're also denoted by a casting mark on the star shaped lifter plate!

https://www.ebay.com/itm/1981-1982-Hond ... _cvip=true
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Re: Clutch animal, don't you just hate this....

Postby jnnngs » Fri Feb 14, 2020 12:42 pm

Chris,

You need to be careful with these bolts.

The correct bolts, there should be:
- 2 longer bolts with a shoulder on them
- 4 shorter bolts which are standard m6 bolts (any m6 bolt of the correct length will do.

The longer bolts should be used with the corresponding holes which have the threads recessed to allow for the shoulder. These longer bolts make it easier to attach the lifter plate, and also help centralise it.

The problem is if you put the two longer bolts into the wrong holes, the shoulder will split the aluminium as it is tightened up.

I am sure Honda were trying to make things easier, but has proven over-complicated for most of us!

Hope that makes sense.

Paul.
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Re: Clutch animal, don't you just hate this....

Postby EMS » Fri Feb 14, 2020 12:47 pm

When a bolt is designated "special" it means it does not confirm to any industry standard, like DIN, SAE or JIS. This means, there could be a shoulder on it or the length is "non-standard" or even the pitch may not be standard for the thread size.
These are 6mm bolts (M6) I do not know if the pitch is standard or the original bolts have a shoulder or a waist.
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Re: Clutch animal, don't you just hate this....

Postby CBX1000chris » Fri Feb 14, 2020 12:47 pm

Thanks Jeff,
This was very helpful, I can now see what it should look like.
Sadly it meant when I went to have a closer look at my clutch and I could see the holes in the lifter plate have been damaged where they've rubbed on the threads of the incorrect bolts. I need to know what diameter these holes should be to get an idea of whether the damage is significant or not. The other problem I might have is the fit of the special bolts into the pressure plate, I won't know how much of a problem this is until I can test it with the correct bolts.

I'd be very grateful if someone can tell me the diameter of the holes in the lifter plate please.

So I now think there are two special bolts with part number 90008415000 and four flanged bolts with part number 957200602508.

I suspect I might be in the market for some clutch parts....

Regards,
Chris.
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Re: Clutch animal, don't you just hate this....

Postby CBX1000chris » Fri Feb 14, 2020 12:49 pm

Thanks gents, the last two replies came while I was in the garage so hadn't seen them before I submitted my previous post.
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Re: Clutch animal, don't you just hate this....

Postby Jeff Bennetts » Fri Feb 14, 2020 1:16 pm

The diameter of the lifter plate holes for the special fasteners should be the same as the inside diameter of the recessed boss towers they mate to.

You have everything in front of you to obtain the measurements you seek and the fasteners you need if the pieces aren't damaged, a depth gauge and set of cheap calipers will do it, $12.00 at Harbor Freight!

You can use the shank end of a non-marred drill bit to get a close inner diameter measurement for the recessed bosses for the spl shouldered bolts, use the digital calipers in the mm setting, use the depth gauge for the other measurements.
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Re: Clutch animal, don't you just hate this....

Postby CBX1000chris » Fri Feb 14, 2020 1:23 pm

Hi Jeff,
The towers have been tapped 1/4" and the threads run to the top of the holes so I can't take an accurate measurement.

Paul - I've sent you a pm.

Regards,
Chris.
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Re: Clutch animal, don't you just hate this....

Postby EMS » Fri Feb 14, 2020 4:50 pm

I measure 6.43mm with a digital caliper for the holes in the lifter plate.

All the clutches I have:

All the lifter plates have a circle at the holes
All bolts have a shoulder, two of them, which are longer, have longer ones
The longer bolts are black, the shorter ones are silver.
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Re: Clutch animal, don't you just hate this....

Postby CBX1000chris » Fri Feb 14, 2020 6:12 pm

Thank you EMS.
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Re: Clutch animal, don't you just hate this....

Postby EMS » Sun Feb 16, 2020 12:38 pm

In case you need to replace the lifter plate, there is one on ebay Germany right now, albeit pricy. Shipping to the UK could also be expensive, now, after Brexit... :teasing-poke: :teasing-poke:

https://www.ebay.com/itm/Clutch-Pressur ... SwA71bn5WV
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Re: Clutch animal, don't you just hate this....

Postby CBX1000chris » Thu Feb 20, 2020 7:30 am

Thank you EMS, I've managed to order a new one.
Regards,
Chris.
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