650SS clutch chainwheel.

Hi.
Cleaning up my clutch assy for the first time and I see I have a different chain wheel (I've always called it a basket ).
My one seems to be made of bronze or something as it's a bronze or copper colour. Instead of the single friction plate that sits behind it, it has a heap of trapeze shaped friction pads that seem to have free movement on the basket.
Can anyone identify this and are they any good. ? Cheers Hillbone

Here's a picture

The copper colour is from manufacturing. Believe it had some effect when heat treating the basket. Completely normal.
The basket with friction pads is from an older clutch. I'm not completely certain but I think they changed clutch when Introducing of the AMC gearbox.
Only Nortons I've had with the older friction pads basket was with dolls head and laydown gearboxes.

Assuming it is otherwise similar to the AMC clutch, you should go a little further and remove the basket and check what is inside (a shock absorber center body, also called a spyder), and what is behind (a roller cage).The spyder has a tendency to break its paddle-like ears.
Also the rubber shock absorber cushions may be gummy and deteriorated.

Slick

hillbone said:

Hi.
Cleaning up my clutch assy for the first time and I see I have a different chain wheel (I've always called it a basket ).
My one seems to be made of bronze or something as it's a bronze or copper colour. Instead of the single friction plate that sits behind it, it has a heap of trapeze shaped friction pads that seem to have free movement on the basket.
Can anyone identify this and are they any good. ? Cheers Hillbone

Click to expand...

From memory, my 1964 650SS was exactly as in your picture.

If looking at AN website the slimline clutch looks like this: https://andover-norton.co.uk/en/shop-drawing/512/clutch-road-models-manx
And the wideline clutch: https://andover-norton.co.uk/en/shop-drawing/886/clutch
Notre that the newer ones has friction plates with inner dogs and the older has friction plates with external dogs. Of course plain plates also different.
Going further back in history, friction pads was not bonded, instead the plates was pierced and had cork inserts. Same with basket.
I think the drum was copper plated so that only the sprocket teeth and the roller race was case hardened.

Mike40M said:

The basket with friction pads is from an older clutch. I'm not completely certain but I think they changed clutch when Introducing of the AMC gearbox.
Only Nortons I've had with the older friction pads basket was with dolls head and laydown gearboxes.

Click to expand...

The clutch pictured is the pre-62 type. 1962 was the year AMC revamped the transmission line of their big twins by introducing the performance clutch and the revised NA/MA type AMC gearbox.

Advent of the performance clutch may have been the result of the Matchless G15Mk1 engine which went into limited production that year (the Atlas banger appeared one year later).

The new transmission and clutch appeared on AJS/M heavy single cylinder models as well.

Introduced Sept 1962 (S/N 104123), the 650SS was almost certainly fitted with the new performance clutch when it was assembled in the Plumstead works.

- Knut