Honda CB750 Sandcast

The Restoration Shop => Engine Mechanical => Topic started by: Wayne on January 26, 2012, 11:41:23 am

Title: Clutch Plate Wear / Replacement
Post by: Wayne on January 26, 2012, 11:41:23 am
Pulled my clutch apart for inspection and cleanup. Will have to replace the friction disks as some have pieces falling out etc. I checked the clutch plates for being warped. All are OK but they do exhibit wear and have been a bit hot I think. Maybe I was a bit hard on this clutch when I was a kid!  ;) From what I can see the plates with indents are no longer available. Is there any advantage to this type of plate over the superceded part? Looking at this plate (it's the worst of all of them) should I just use it or replace them?
Title: Re: Clutch Plate Wear / Replacement
Post by: Riccardo on January 27, 2012, 08:27:32 am
In my first restore i replaced the clutch disks with new type.
No good idea.
The clutch was not soft but hard/nervous in the touch during the lever release.
I replaced then the new disks with the old (indent)......they are better!
Many attemption when You assemble  the clutch, observe the part list in the sequence plate/ferodo/plate...ecc.
Expecially in the start of the sequence.
Title: Re: Clutch Plate Wear / Replacement
Post by: markb on January 27, 2012, 10:10:51 am
I'd measure them in several spots to make sure the thickness is consistant and if they're not warped I'd run them.  I look at how hard it would be to replace something later.  If I had a gear that looked suspect I'd replace because of the difficulty of doing it later.  But if you had to you can always get at the clutch without a lot of work.
Title: Re: Clutch Plate Wear / Replacement
Post by: Steve Swan on January 27, 2012, 11:51:36 am
I don't/won't use Barnett clutch plates.  Their fibre is used is to minimize slippage in racing conditions, the Barnett's are hard on transmission gears.  The action is much more direct, not a smooth gradual release.  I only used a set once and took them out soon after i installed them.

Unless the steel plates have been really overheated, causing warpage, as Mark says, they're not warped, the can be used.
Title: Re: Clutch Plate Wear / Replacement
Post by: Wayne on January 27, 2012, 12:40:41 pm
Thanks folks. I did check for warpage by placing the plates on a sheet of glass and measuring at different locations around the perimeter. The Service Manual calls for anything over .012 warpage to be replaced. I used a .008 feeler gauge and it didn't slip under in any spots. I'm going to go ahead and order up new friction disks and springs from Honda and go from there. I was thinking the same way Mark was, this can easily be fixed later if there is a problem.
Title: Re: Clutch Plate Wear / Replacement
Post by: benjixt on March 14, 2012, 05:05:59 pm


dear all,
i just check the clutch , on the part list you start the sequence ( plate ferodo plate etc )   by a plate however on the honda manual the sequence start by a ferodo ( when you check the first drawing)
http://www.hondacbfour.com/download/man_officina/pdf_manuali/CB750_K0_K1/Cap_04.pdf (http://www.hondacbfour.com/download/man_officina/pdf_manuali/CB750_K0_K1/Cap_04.pdf)

what is the correct one???

thank you
Title: Re: Clutch Plate Wear / Replacement
Post by: benjixt on March 16, 2012, 01:28:29 am
any specialist about this subject??
 ;) ;)
Title: Re: Clutch Plate Wear / Replacement
Post by: Wayne on March 16, 2012, 11:02:22 am
Benji
Early bikes have 7 friction disks and 6 loose plates. The first clutch plate (#6) is locked in place by the clutch plate stopper ring. (#11) The last (outside) friction disk is a smaller diameter disk (#5) and sits inside the clutch outer ring. So really what the diagram is showing is to start with the first Clutch plate (#6), then the small friction disk (#5) and then alternate the remaining steel plates (#7) and larger friction plates (#4). Based on the number of plates you will finish with a friction plate against the pressure plate. (#8)

A quick look at the diagram make you think you would put a steel plate against the pressure plate. Not so! Friction plate on the pressure plate, friction plate against the outside plate (#6) and alternate everything in between. NEVER steel on steel. (or aluminum)

This is for an early bike with the number of plates I have shown. I think I read later bikes may have additional plates to combat rattle? From a Goldwing???