The Pete Kirby Clutch.

All Photos Courtesy Otterman and Pete Kirby.

Phone number 07886745942

30/09/2026...

We take a look at the work of art that is the clutches built by top engineer Pete Kirby to fit BSA Unit Singles, Triumph TR20 Tiger Cubs, and Ariel HT trials machines. These clutches drive through a Powerful Gates PowerGrip  reinforced belt from the specialy geared pully fitted to the engine crankshafts, and are well known for there reliability and superb action.

At this time in 2026 they are currently not being built until Peter has undergone his pending back operation and recovery. 

But spares for the clutches may be available later this month October . So below are photos of the parts that go into making this superb part of British Classic motorcycling.

The rear view of the beltwheel and bearing assembly...

This clutch is for a BSA Unit single ...

The bearing number is Craft 6007 2Rs C3... 35 x 62 x 14 mm.

These are the parts that come with the kit including pullers,  spring compressor, and locking tool...

These are the friction plates that most people have asked me if they are still available... Most are Pete tells me and if you ring him on the number above he may be able to supply them.

The other itom that a lot of you have asked me for information is the 140mm internal  Smalley EH-140 Spirolox spiral retaining ring. You must check with Pete to see if he has these available aswell...

This is how you should fit and remove these retaining rings so has not to damage them.

The superb beltwheel of the clutch, and you can see the two threaded holes in the centre hub for fitting the Bridge puller to remove the clutch from the gearbox mainshaft.

This is the actuating top plate that the diaphram spring puts the preasure on, this is a superbly machined item, and needs looking after.

This is just a start of this page and it will be worked on again shortly.

Updat 09/2026...