clutch springs

[DAVE BRADY]

Hi,

Springs for the early 4 spring clutch are very hard to find.  I have checked all the mainstream suppliers but to no avail. They all offer springs that are 50mm long as opposed to 40mm so 10mm too long.  Does any one know of obscure supplier out there or an alternative part number to 68-3237.

There is a Triumph spring that is 45mm that may do but could still get coil bound.

Any ideas/suggestions?

Dave.

[Cmcl.1959]

Hi Dave,
I've encountered the same problem with the four spring clutch on my 1965 A65R Rocket.
According to the workshop manual I have, the springs should be 1 11/64" (42.4635mm ) with 6 3/4 working coils.
I bought some from eBay but they were 50mm and 10 coils and when I queried it the supplier said basically that was what was available with that part number.
I tried Draganfly and bought new clutch plates and springs from them but the springs were the same 50mm length and the plain plates didn't fit without filing each one. I emailed them about this but got no reply.
The workshop manual I have also covers the 650 Star and it lists springs for it as being 1 35/64" 39.2907mm so might be suitable for you if someone knows where to get them.
Hopefully someone will know a supplier.
Regards
Clarke

[DAVE BRADY]

Hi Clarke,

The correct springs seem to be available in the USA, Australia and NZ but the shipping cost looks prohibitive.
I may explore these possibilities a bit more or give the Triumph ones a go.

The plain plates are specific to the early 4 spring clutch.  Also the screw 68-3215 that secure the cush drive seems to be in short supply other than from overseas suppliers.
Some in the UK are offering some that are a bit short and do not have the deeper countersink that the originals have.
I will keep looking as I think that this early clutch is very good with its extra thrust washer helping to keep every thing stable.

Dave.

[Cmcl.1959]

Hi Dave,.
Do you have a part number for the Triumph springs and a supplier?
They might be a standby for me too, as the other springs are far too long.

Cheers
Clarke

[DAVE BRADY]

Hi Clarke,

This should be the link.  They are T140 '73 to'85 part number 57-4644

https://www.classicbikeshop.co.uk/media/catalog/product/cache/8552b5243cc5d1b6fbe4d987a7b66454/f/4/f400809a9bee84f61f1a9ce0b86bbe44.jpg

I have bitten the bullet and ordered some springs from the Baxter Cycle in the USA.  I also ordered the screws from New Zealand.

'Coal to Newcastle' is quite apt I think.

Dave.

[Gup holland]

Just read this topic, last year i had the chance to buy a new old stock 4 spring clutch to change with mine 3 spring clutch.
The springs that go with it measured 43,8 mm, this should be the right ones.?

[DAVE BRADY]

Hi,

The length that I have for the early 4 spring with the 2 thrust washers is 1 35/64" or 39.2907mm.
I would imagine that your 43.8mm will be ok and that there was probably some production variation.

My old ones have 8 coils.  Any more than this and the spring could become coil bound.

Do you have image of the back of the clutch?

Dave.

[Gup holland]

Hi dave,

The springs here are also 8 coils, took some pictures. Bit off topic, do you know what is the best way for lining the chain is? How to measure this, from casing? How to calculate the shims behind the front sprocket.

[DAVE BRADY]

Hi,

I think this was the best design fitted to the A50/A65.  If it had one more friction/plain plate pair it would have been ideal.  I imagine that BSA found it a lot cheaper to make the later clutch due to a more simple design.
Shimming to get the chain in line can be  bit time consuming but you may be lucky and it will good be from the start.
You need to remove the alternator and the front sprocket. The shims go between this and the crank spacer.
Put the clutch on but not fully tightened but enough top stop wobble.  Put the front sprocket on and again tighten enough to stop any movement.
Hold a straight edge across the outer edge of the clutch teeth so that it is touching as much as possible.
Now look at the front sprocket and see if there is a gap or if it is keeping the straight edge from proper contact with the clutch.
If the straight edge is being pushed out then then any shims should be removed.
If there are no shims then a thinner crank spacer is needed - I think there 3 available.
If there is a gap between the straight edge then measure it and this is how much shimming is needed.
If the gap is quite large a thicker crank spacer may be needed rather than lots of shims.
Once the alignment is satisfactory do final assembly with the chain fitted but before final torquing recheck with the straight edge along the chain.

Because the centres a relatively close there should be no misalignment but in reality a few thou should be OK.

I hope this makes sense.

Dave.

[DAVE BRADY]

Hi,

Just a comment re order from Baxter Cycle in the USA. They sent a message containing this. Due to "current import tariffs in the UK all orders must be at least 200USD".  Shipping on top so.....
I have been refunded rather try to up my order with things I can get in the UK or did not really want.

Dave.

[Gup holland]

That's what I thought about lining the chain, maybe there was an other way. But this works. I'm rebuilding my engine, so start from scratch.
I've made one shim al ready for the crank end float instead of 3 shims.

Gup

[DAVE BRADY]

Hi,

An update on the Triumph springs mentioned above.
They turned up today and I have managed to fit them after lot of effort. Not yet properly adjusted so they may still get coil bound.
The gauge of the spring is a bit heavier so it may be possible to shorten them a bit if needed and still have stronger springs.
Maybe have another go tomorrow.

Dave.

[DAVE BRADY]

Hi,

When the Triumph springs are adjusted up the lever is harder to pull in and they are almost coil bound.
If push come to shove then they could be shortened by one coil.
Has anyone tried shortening a clutch spring?

Dave.

[EDDIE SIMPSON]

hi dave , just seen this post.
i have a 4 spring clutch and went over to the 7 plate conversion. it really does make it a better clutch.

[EDDIE SIMPSON]

i used kawasaki 500s clutch springs on one bsa once and remember  they were perfect. however not cheap even second hand.