A pre-unit Triumph four spring clutch is the easiest one to fit. You want the early version without the shock absorber in the clutch center. You will also need an adapter for the main shaft, I got mine from KIdderminster motorcycles. It is easy to install and you will end up with a clutch that actually works.
Make sure you specify the adapter is for a WM20 or you will end up with one for a BSA B series which will not fit properly.
I used to get M20 clutch plate sets made in an oil proof material by Saftek Ltd....An added bonus to their use was the deletion of the 'top hat' cover which not only is held in place by multiple screws but also traps within the clutch the material which wears of the fibre plates. The resultant mess affects the operation of the clutch over time...
Regarding pattern plates many of them are thicker than the originals...The consequent accumulated extra hieght in the clutch plate pile leaves insufficient space in the basket for the plates to seperate and also cancels out any gain when using the old 'dodge' of leaving out one metal and one fibre plate...The correct fibre plate thickness should be .093" when new....
When the single spring clutch is worn in other areas as well as the plates a change to the Triumph clutch is a sensible option as noted by Bruce...Everything for that clutch is readily available...Personally, I favour parts made by LF Harris as in my experience they are consistently of good quality and fit...I've made a number of previous posts about the parts required to make the conversion and that would probably come up on a search of the forum....
I'm currently looking at converting the Triumph clutch from loose rollers in a track to a sealed bearing set up...That would improve the Triumph clutch considerably as well...I did a similar mod. when I fitted a Triumph clutch to my WB30 with good results....Ian
Hello again , just say thank you to all with the info ,would any pre-unit triumph clutch do i wonder , now it`s trying to find one , the bike is been strip down to the last nut and bolt as it was in a poor condition when i got , all the bit have been cleaned back to the bear metal and not being put back together again , , once again thank all , regards Peter
