Honda-SOHC

SOHC.co.uk Forums => CB750 => Topic started by: brodsord on April 19, 2020, 08:10:55 PM

Title: Clutch slip
Post by: brodsord on April 19, 2020, 08:10:55 PM
Hi everyone,
So I’ve got the old girl out for a quick road test.
F2 frame k5 engine.
All is good but Clutch is slipping after second gear.
Last time she was on the road was 1998.
Fresh oil in her etc and I’ve adjusted the clutch as per manual, do i need to replace clutch or is there something else I can do ?
Many thanks,
Gray


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Title: Re: Clutch slip
Post by: Trigger on April 19, 2020, 08:20:24 PM
The manual is incorrect on the settings. Plates go hard and brittle after years  ;)
Title: Re: Clutch slip
Post by: brodsord on April 19, 2020, 08:21:31 PM
Thanks G.
Should I replace them then?


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Title: Re: Clutch slip
Post by: Trigger on April 19, 2020, 08:30:20 PM
My Honda crystal ball needs upgrading at the moment so, I can't see your clutch plates. Try setting the clutch in reverse of what the manual states  ;)
Title: Re: Clutch slip
Post by: brodsord on April 19, 2020, 08:37:13 PM
Ok thanks G I’ll have fiddle tomorrow.


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Title: Re: Clutch slip
Post by: Lobo on April 19, 2020, 11:08:49 PM
...there’s been past threads commenting on how modern synthetic oils can promote clutch slip (dependant upon the additives); are you using good old cheap mineral oil? (tho’ if it’s slipping in 3rd perhaps the issue is indeed more significant than oil...)
Anyways, Google it... the jury seems to be out on this one...
Title: Re: Clutch slip
Post by: brodsord on April 20, 2020, 09:02:25 AM
Thanks Lobo,
Yes mineral oil is what’s in there.
Ill have a google this morning


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Title: Re: Clutch slip
Post by: brodsord on April 28, 2020, 05:58:21 PM
Hi All,
I’ve taken the clutch out the friction plates all measure around 2.40 to 2.70 ish mm
Back friction plate in the picture below looks
Mullered.
The pressure plate also has been broken, it had been epoxy resined which was holding, am I ok to weld the broken tab back on or should it i get a new one?
Also do I have to remove the inner clutch basket to fit new clutch plates or can just assemble them into the basket in situ on the bike?
Thanks for any help
(https://uploads.tapatalk-cdn.com/20200428/4bfa03ed5502084147a33bd83e24c950.jpg)
(https://uploads.tapatalk-cdn.com/20200428/1201e9f1ddb1aebd5bea02584e7835f9.jpg)
(https://uploads.tapatalk-cdn.com/20200428/0546f99879cac11365f5ad6927995b82.jpg)


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Title: Re: Clutch slip
Post by: Nurse Julie on April 28, 2020, 06:31:50 PM
Definitely get a new / replacement clutch lifter plate. Those corners snap off for fun at the best of times. If you can't find a new one to buy, we have loads of good used ones here.
Title: Re: Clutch slip
Post by: philward on April 28, 2020, 06:42:49 PM
Mike Smith at 'good-stuff' (he is a dormant forum member I think) does this upgraded plate he uses for his racer - https://good-bits.co.uk/product/cb750-sohc-clutch-actuating-hub/
Title: Re: Clutch slip
Post by: Bryanj on April 28, 2020, 06:46:32 PM
With a fibre worn that bad i would suggest a full set of fibre and steel.
That plate gets wrecked when the centre outer plate is put on wrong, it only fits in certain places
Title: Re: Clutch slip
Post by: Trigger on April 28, 2020, 07:37:41 PM
New plates all round.
I would also fit a replacement lifter plate, new lifter bearing  and do you have a double plate in the stack ?
Look for grooves in the surface of the plate, clutch and the center, clutch  ;)
Title: Re: Clutch slip
Post by: brodsord on April 28, 2020, 07:59:55 PM
Thanks all for your reply’s.
Hi Trigger yes it has the double plate in the middle.
I’ve just sent Andy at good bits a message to see if he is still doing internet orders, he has an updated lifter in his web shop and a complete clutch kit.
Is the double metal plate specific to different models?
Thanks
Gray


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Title: Re: Clutch slip
Post by: brodsord on April 28, 2020, 08:01:47 PM
There’s no grooves I meant to add, the plates are smooth, they seem to have a diamond pattern etched in the surface


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Title: Re: Clutch slip
Post by: brodsord on April 28, 2020, 08:04:03 PM
Mike Smith at 'good-stuff' (he is a dormant forum member I think) does this upgraded plate he uses for his racer - https://good-bits.co.uk/product/cb750-sohc-clutch-actuating-hub/
Thanks Phil, I’ve spoke with Andy at good bits a few months back, very helpful fella, I forgot about his shop so thanks for heads up


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Title: Re: Clutch slip
Post by: brodsord on April 28, 2020, 08:05:56 PM
With a fibre worn that bad i would suggest a full set of fibre and steel.
That plate gets wrecked when the centre outer plate is put on wrong, it only fits in certain places
Thanks Byran,
I’ll probably need to pick your brains if that’s the case when I get the new clutch


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Title: Re: Clutch slip
Post by: brodsord on April 28, 2020, 08:06:53 PM
Definitely get a new / replacement clutch lifter plate. Those corners snap off for fun at the best of times. If you can't find a new one to buy, we have loads of good used ones here.
Thanks Julie, I’m going to see if I can get an updated plate as per Phils message below


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Title: Re: Clutch slip
Post by: Trigger on April 28, 2020, 10:32:18 PM
There’s no grooves I meant to add, the plates are smooth, they seem to have a diamond pattern etched in the surface


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I think you have misunderstood on what parts to check for grooves. It is the area that I have marked in Yellow.
The double plate was a upgrade on the later 750 engines. Many different clutch baskets and fiber plates on a 750  ;)

[attachimg=1]

Title: Re: Clutch slip
Post by: brodsord on April 28, 2020, 10:52:54 PM
Thanks Trigger,
Yes I’m a bit confused. I will check those in the morning to see if they have grooves in them, if they have will they need to be replaced?


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Title: Re: Clutch slip
Post by: brodsord on April 29, 2020, 08:57:35 AM
Morning Trigger,
Those metal areas that you have highlighted in the picture have no grooves at all there completely smooth.
Does that mean there ok?


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Title: Re: Clutch slip
Post by: brodsord on April 29, 2020, 08:58:03 AM
Thanks,
Gray


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Title: Re: Clutch slip
Post by: brodsord on April 29, 2020, 10:40:55 AM
I’ve taken a few pictures,
The steel plates  that go between the fibre plates, two have small circular almost like punch marks in them, two of them are more flush then there’s a plate that is two plates joined together again this plate is smooth with no punch holes. Are these normal or do they need to be replaced?
Thanks,
Gray
(https://uploads.tapatalk-cdn.com/20200429/549930f3c697d00e32b5535517977314.jpg)
(https://uploads.tapatalk-cdn.com/20200429/45af429d1f57f8faef5baec9ffb550ea.jpg)


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Title: Re: Clutch slip
Post by: Bryanj on April 29, 2020, 11:03:07 AM
 The worrying one is the one that has some punch marks but some plain on it which means uneven wear like the one fibre.
The double plate was a mod by Honda to try and stop clutch "rattle"
Due to the abnormal wear personaly i would replace all the fibres and plain steel plates plus the springs, the double plate is probably fine to reuse as its thicker and also discontinued.
It was probably all caused by that broken lifter plate putting uneven tension on the clutch.
Title: Re: Clutch slip
Post by: brodsord on April 29, 2020, 11:07:40 AM
Thanks Bryan, I get those ordered then


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Title: Re: Clutch slip
Post by: Trigger on April 29, 2020, 11:40:35 AM
Looks like someone has been in there before  ;)
Title: Re: Clutch slip
Post by: Bryanj on April 29, 2020, 12:15:16 PM
Before you order check how many of each plate you need as it wont be as per parts book due to the mod plate.
If you are getting the lifter plate from Julie might be worth asking her to supply.
Title: Re: Clutch slip
Post by: brodsord on April 29, 2020, 12:15:34 PM
Looks like someone has been in there before  ;)
Don’t know wetter it’s a good or a bad thing


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Title: Re: Clutch slip
Post by: brodsord on April 29, 2020, 12:20:20 PM
Before you order check how many of each plate you need as it wont be as per parts book due to the mod plate.
If you are getting the lifter plate from Julie might be worth asking her to supply.
Thanks Bryan, I didn’t realise Julie sold all parts I’ll message now for cost


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Title: Re: Clutch slip
Post by: Bryanj on April 29, 2020, 02:27:59 PM
The number of 750's Trigger builds i would be surprised if they didnt have any!
Title: Re: Clutch slip
Post by: brodsord on April 29, 2020, 02:43:25 PM
The number of 750's Trigger builds i would be surprised if they didnt have any!
Good to know thanks Bryan


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Title: Re: Clutch slip
Post by: brodsord on April 30, 2020, 03:10:51 PM
Hi All,

Does anyone have a method how to remove the clutch lifter piece  out of the bearing in the clutch plate?
Thanks,
Graham


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