Hi guys
I've got a bsa a65 1967 and the previous owner put a 4 spring clutch in it, I'm having problems with clutch slip, when stripping it I noticed the last pate to come out was a plain plate and only 5 friction plates in total is this correct.
According to the parts catalogue there should be 5 friction plates and 6 plain plates for the 4 spring clutch if your clutch is set up correctly and it is still slipping maybe the springs need to be the tension springs are weak and need replacing.
Hi Spike,
It is worth checking that the plain plates are flat. Over time and especially if the clutch has been over heated then they can get a bit warped. Replacement is the only option. I think that getting them pressed flat would be very difficult as they may then spread and need quite a bit of fettling to them to fit properly.
If you put them in a stack and see how much wobble there is when squeezing the edges. If only very small gaps appear then they will probably be OK but lots of wobble will manifest itself as a difficulty in setting up the clutch and some annoying drag.
If you get new ones, check them for wobble as I had some that were worse than the old ones. Be prepared to send them back.
Dave.
Thanks guys
But dose the plain one go in first and what about the the thicker plain one which I presume goes on the outer
Hi,
The thicker plain one goes in first as it takes the pressure of the clutch. Then friction, plain, ending with a plain plate and then the pressure plate.
Dave.
The clutch center has a "step" in the grooves where the first, heavier plate goes on.
(https://i.imgur.com/R68olsJm.jpg)
Hi,
I forgot about the step but it is important that the thick plate is hard against the clutch centre to get it square.
Dave.
Thanks looks like the plain plate was the wrong way around, I've checked the plain plates are flat but the thick plain plate was against the pressure plate so now I know I'll swap it around
Thanks guys
Quote from: DAVE BRADY on 17 Aug, 2021, 14:49
Hi,
I forgot about the step but it is important that the thick plate is hard against the clutch centre to get it square.
Dave.
Should have explained my photo. Good catch.
I have a new 4-spring clutch on my B31 and am experiencing some slip. All steel plates (6 off) are all .074" thick. How thick is the thicker plate on the clutches mentioned above?
Not stating the obvious, but when you assembled the clutch you did start with a steel plate first. Don't ask how I know. It does help if you dump the steel pressure plate and fit an alloy one. There is a few companies making them.
Just measure an A65 4 spring plain plate and a A10/B31 4 spring type plain plate and both are approximately 2 mm thick. Dont know about the thicker A65 item.
The 2 types do not interchange because the tangs on the A65 plates are sloping not square as the A10 type and the channel in the A65 centre is machine to accept the sloping tangs.
Photo shows the A65 4 spring plate on top of A10/B31 4 spring plate.
Hi,
The different shaped tangs are a definite in the early 4 spring clutch that had the captive thrust washers etc. Did BSA go straight from this to the 3 spring? I have a 4 spring in one of my A65s that takes the same plates as the 3 spring and does not have the washers and centre all held by screws as a unit.
The thicker plate is probably only in the early A65 4 spring. The thicker plate takes the pressure of the clutch as I do not think it comes in to contact with the back of the clutch basket. A10 plunger 6 spring also have the thicker first plate.
Dave.
:) :) :)
A brief thought. Do you have the correct spring cups.
I believe the 3 and 4 spring clutches had different depth cups. I can't recall the details but I'm sure it would make a difference.
Mike 8) 8) 8) 8)
Quote from: idie on 19 Aug, 2021, 18:11
Not stating the obvious, but when you assembled the clutch you did start with a steel plate first. Don't ask how I know. It does help if you dump the steel pressure plate and fit an alloy one. There is a few companies making them.
Yes the steel which reacts the spring load did go in first and the clutch was supplied with the alloy pressure plate. The wear markings on the steels seem to indicate to me that the first steel is dishing under spring load and that's why I was interested in the previous comment about a thicker first plate. My supplier has confirmed that this clutch is correct with six identical steels. I did consider putting an additional steel in against the first one but the last steel under the pressure plate would be perilously close to coming off the hub with the clutch lever pulled in. My quest for satisfactory performance continues.