850 or 750 Clutch Basket?

I have a 1974 Mk2a 850 Commando. Talking to someone with a 750 today he was saying that the 750 clutch basket has the 'back plate' pre attached inside the basket and that the 850s didn't have this. Mine has the fixed plate at the back of it, and so he was suggesting I have a 750 clutch basket. Is this true?

Also my owners manual, which is for 750 and 850 specifies only 4 friction plates each at 0.148" - 0.142" thick. Being that mine's the 850 I obviously have 5 friction plates, but I can't see anywhere what the thickness of them should be? Mine are roughly 0.12"

Also my pressure plate sits slightly inside the basket, by about 0.098" – is that ok?

My clutch is really heavy, which is why I'm trying to figure this stuff out...

Post a pic of your clutch internals/plates ?

Anything could have happened to it over 40 years, and Nortons had a few different versions of friction plates etc, as well as 3rd party Barnett plates etc...

Read all this, very important stuff

http://atlanticgreen.com/clutchpak.htm

http://atlanticgreen.com/ndnsclutch.htm

Yeah sure will photograph it today.

Thanks for those links! That's good info, exactly what I was after!

Headfullofsnakes said:

Yeah sure will photograph it today.

Thanks for those links! That's good info, exactly what I was after!

Click to expand...

All the credit goes to Dynodave, who invested lot's of time, effort and wisdom. :idea:

Headfullofsnakes said:

I have a 1974 Mk2a 850 Commando. Talking to someone with a 750 today he was saying that the 750 clutch basket has the 'back plate' pre attached inside the basket and that the 850s didn't have this. Mine has the fixed plate at the back of it, and so he was suggesting I have a 750 clutch basket. Is this true?

Click to expand...

The back plate on the 750 clutch basket was pinned to the basket with 2 small steel dowels. The plate and dowels are removeable. The 850 basket had the back plate riveted in place. The overall inside dimensions are the same, so it doesn't matter which you have in terms of clutch stack-up.

Also my owners manual, which is for 750 and 850 specifies only 4 friction plates each at 0.148" - 0.142" thick. Being that mine's the 850 I obviously have 5 friction plates, but I can't see anywhere what the thickness of them should be? Mine are roughly 0.12"

Click to expand...

Nominally .125" and it's in the specs. Those were bronze plates for the 850.

Also my pressure plate sits slightly inside the basket, by about 0.098" – is that ok?

Click to expand...

Seems like a lot. Shimming with an extra .080 steel plate could make a huge difference in clutch effort.