Having problems with my clutch it’s not disengaging spuarely in the basket put new spring in it ,but no difference taken a steel and friction plate out still the same scratching my head as to what the problem is anybody else had the same problem? Thanks

It sounds like you have replaced one crooked spring for another, this came up as a topic a few years ago, I suspect that these springs, sometimes even new old stock are deteriorating through time, although a REME fix was created back in the late 1940s?

So you have the option of sourcing another replacement or working with what you have.

Rob

email (option): robmiller11(a)yahoo.co.uk

I expect the problem lies with the quality of the other parts.
The inner and outer hub must not be dogged.
The plates must be flat.
I have a single spring clutch in my M20 and it's very nice.

Mark

email (option): pes.sales@btconnect.com

Aloha,

Make sure the clutch rollers are 1/4" x 1/4". I was sold longer ones and the clutch did not work, tried every possible remedy before it dawned on me while I was calmly looking out a train window what the real problem was.

Best regards,

Simon

I had the same problem as you. First the rollers in the clutch basket were the wrong size, original spring was not straight. Bought a NOS one and had the same problem...

Then I bought this:

https://www.thb-support.nl/product/bsa-m20-koppeling-centrale-veer-vervangings-set-15-4311-15/

Works perfect! I can pull the clutchlever with one finger.

Or get a complete kit with modern kevlar plates:

https://www.thb-support.nl/product/bsa-m20-complete-kevlar-koppelingsset/

I don't understand why anyone bothers with the BSA single spring clutch? It most certainly can be made to work and is probably better the the BSA six spring clutch, but it is still a cheaply made piece of junk.

If the bike is ridden very little it will work OK for many years. But if you are touring and putting miles on the bike with your camping gear and possibly a wife, the clutch will have a hard life and one day you will be at your camp site with the primary off trying to figure why it is slipping or other problems. You mates will be drinking beer while you try to fix things. They all have a Triumph clutch in their M20 which can stand the abuse of a 650cc OHV motor and won't need any attention for many years.

Getting rid of the single or six spring clutch is probably the best improvement you can make to the bike.

Hello Bruce

this is all very interesting about the single spring clutches apparent weakness. What triumph clutch should one be looking for that would replace it and are there any special mods other changes that would be required?

cheers
Neil

email (option): nlhclarke@gmail.com

Well I've run both my 600cc M20 and my BSA/Indian special with the single spring clutches for many years, both with one friction and one steel plate removed. Light as a feather with no slip or drag.

However the Indian engine has no cush in the primary circuit and it could be a bit harsh at low speeds, so after about 10 years, I replaced it with a Bonneville clutch with rubber cushions built in. It's absolutely perfect now.

But for an M20 you won't need a cushioned clutch, so a basic Bonny clutch would be fine, but you do have to have the correct adapter.

I bought my complete kit from "Monty's" Triumph Motorcycles in Devon. Ron

email (option): ronpier@talk21.com

You'll need a complete clutch for a pre unit Triumph twin..(Bonnie, T110 etc.) with a non shock absorber centre...Also the correct clutch sleeve adapter for M20 applications..There are two possible clutch spring types, short heavy ones and longer, lighter ones..The latter are best for use on single cylinder bikes. You'll also need the BSA clutch centre nut and washer, not the Triumph one...
Monty is a longtime friend and lives near me. Consquently he's familiar with what's needed but make sure you tell him it's for use on an M20...He supplies L.F. Harris parts which I'd recommend as the best...Ian

One more question.
Is it a good idea to leave out 2 plates (a steel and a friction) on your single spring M20 clutch ?
I want to give it a try, maybe it helps in my endless struggle with false neutrals.

It's not a modern bike, feel the pedal as you move it. Get pressure on the lever until you feel it engage.

Mark

email (option): pes.sales@btconnect.com

Yes, leaving out two plates is a good idea as it allows more room for the plates to seperate but has no adverse effect on the operation of the unit...Note that original fibre plates are .093" thick when new...Many pattern plates are too thick by quite a margin..In that case removing two plates will restore the plate 'pile' to the original height but won't provide any more clearance than the standard set up....Ian