I now have another question which is wide open for anyone:
I have the 4 spring Triumph clutch ready, and I ordered the center nut. I did my research and requested 42-3171. The supplier said this had been superseded by 42-3267.
It arrived, and it doesn't fit. It's about 7 thou too small.
There's nothing wrong with the mainshaft thread and the original center nut 15-0374 fits neatly. As far as I can tell this is 5/8 x 26 TPI thread.
Am I dealing with a poor quality nut, 42-3267? Or is this in fact a totally different part? What should I have? And where can I find one?
So far the mailing from England to the US has meant that each mistake costs me far more to mail back than the original order......
If I can be sure of the thread size I could even order up a tap and modify what I already have.
I bought a complete assembly from Draganfly.
First - the clutch is great. Very light and plenty of "feel". Well worth the money. Very easy to fit and adjust.
This assembly came ready to fit and is listed as part number BSA4SPR5