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Identification of the clutch on my dom 88

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I have a hybrid 88 which started life as a single then had the motor replaced. Other parts have been added from maybe older doms ( model 7?)

My problem is a slipping clutch and I cant seem to identify where it came from. Ive replaced all the plates but pictures ive seen of the sprocket should show a plain item but I have friction inserts in mine. I also have a plain backplate on the clutch centre assembly.

When all the plates are in place they come to the very edge of the sprocket slots and the outer plate is in danger of disengaging from the slots

Grateful for any identification leads so that I know what to source to make it work.

Permalink

The classic Norton clutch has a plain back plate and replaceable inserts in back of the clutch sprocket, and all of the friction plates with tabs out. The plates with tabs in are all plain steel. At some point this was reversed.

Are your friction plates original type with inserted friction pads, or later ones with rings of bonded friction material? It is possible that the friction material is too thick for the number of plates. Consider fitting one fewer pair of plates. That is OK - the Manx clutch has fewer plates than roadster ones and has no problem coping with a single giving over 50 bhp

Paul

Previously jonathan_banyard wrote:

I have a hybrid 88 which started life as a single then had the motor replaced. Other parts have been added from maybe older doms ( model 7?)

My problem is a slipping clutch and I cant seem to identify where it came from. Ive replaced all the plates but pictures ive seen of the sprocket should show a plain item but I have friction inserts in mine. I also have a plain backplate on the clutch centre assembly.

When all the plates are in place they come to the very edge of the sprocket slots and the outer plate is in danger of disengaging from the slots

Grateful for any identification leads so that I know what to source to make it work.

Permalink

Previously paul_standeven wrote:

The classic Norton clutch has a plain back plate and replaceable inserts in back of the clutch sprocket, and all of the friction plates with tabs out. The plates with tabs in are all plain steel. At some point this was reversed.

Are your friction plates original type with inserted friction pads, or later ones with rings of bonded friction material? It is possible that the friction material is too thick for the number of plates. Consider fitting one fewer pair of plates. That is OK - the Manx clutch has fewer plates than roadster ones and has no problem coping with a single giving over 50 bhp

Paul

Previously jonathan_banyard wrote:

I have a hybrid 88 which started life as a single then had the motor replaced. Other parts have been added from maybe older doms ( model 7?)

My problem is a slipping clutch and I cant seem to identify where it came from. Ive replaced all the plates but pictures ive seen of the sprocket should show a plain item but I have friction inserts in mine. I also have a plain backplate on the clutch centre assembly.

When all the plates are in place they come to the very edge of the sprocket slots and the outer plate is in danger of disengaging from the slots

Grateful for any identification leads so that I know what to source to make it work.

Thank you, Paul. It seems that I have the standard clutch but pictures on the Norvil site indicate that the sprocket is plain so I'm still a bit confused. Could I have a model 7 or a single clutch?

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Thanks Philip. Your picture of the 49 - 56 clutch is the one. Mine is missing odd bits but basically the same.

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The second exploded diagram showing a clutch with friction sprocket + outer basket is correct for any bike with a Norton gearbox, ie 1934 - '56. Note that the pressure plate is steel, and there is a 'lifter mushroom' (like a penny on a stick)' between clutch pushrod and pressure plate. This is to give more even clutch plate lift. Make sure your clutch springs are of even length and spring strength - I found the original ones are very variable in length, so get some new ones which are matched

I think the early AMC boxes got a slightly modified clutch with an alloy pressure plate and adjuster screw in the centre. At some point, I think it may have been when the AMC 2 box was brought out in 1960, the plates were reversed as in the second diagram

Paul

 



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