BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: nige63 on 25 Mar, 2024, 11:09

Title: M21 Clutch problems
Post by: nige63 on 25 Mar, 2024, 11:09
Hi I am trying to put in my 6 spring clutch but having problems with the bearings. When I try to put them in the outer bearing ring they are so tight that the chain wheel will not move. I have tried Draganflys new cage bearings with no luck. A mixture off outer rings inner rings new and old. Managed to get one to spin but as soon as it was tightened no spin :-\.
Title: Re: M21 Clutch problems
Post by: neil1964 on 25 Mar, 2024, 22:56
Give this thread a read. Everything to consider is in there and although there are areeas of excessive detail it is useful in getting a good working clutch:

https://www.britbike.com/forums/ubbthreads.php/ubb/showflat/Number/872178/Searchpage/2/Main/71633/Words/6-spring+clutch/Search/true/re-bsa-6-spring-clutch#Post872178 (https://www.britbike.com/forums/ubbthreads.php/ubb/showflat/Number/872178/Searchpage/2/Main/71633/Words/6-spring+clutch/Search/true/re-bsa-6-spring-clutch#Post872178)

The bearings will fit with the cages in certain orientations but if you have the wrong combination it will lock up
Title: Re: M21 Clutch problems
Post by: nige63 on 26 Mar, 2024, 05:35
Thanks neil1964. That is some read. I will keep trying. Have another new outer ring and bearings coming this week.
Title: Re: M21 Clutch problems
Post by: Dan_B33 on 01 Apr, 2024, 18:41
This is good one!
You think you have good clutch in your hands....then you read this article....and reality is a bit different.
Thanks for recalling
Title: Re: M21 Clutch problems
Post by: nige63 on 02 Apr, 2024, 07:31
Still can't get mine to spin once the nut is tightened.
Title: Re: M21 Clutch problems
Post by: neil1964 on 02 Apr, 2024, 15:55
Does your basket have protruding rivets at the back?
What happens if you leave all the clutch off except the hub and then tighten the nut up (ie is it a gearbox input/output shaft issue?
Title: Re: M21 Clutch problems
Post by: nige63 on 03 Apr, 2024, 05:47
I will check this today. Thanks neil1964
Title: Re: M21 Clutch problems
Post by: Dan_B33 on 04 Apr, 2024, 09:47
It looks like while you tighten the nut against inner basked the big basket is pushed against big disk sitting behind it
Something wrong with your basket or bearing race.
Inner basket shall rest on washer and washer shall rest on teh bearings race. That shall not influence big basket pressure against disk at all.

Others can state if I say rubbish.

Dan
Title: Re: M21 Clutch problems
Post by: Dan_B33 on 04 Apr, 2024, 10:17
And if that has not been true . Then as Neil said....fitting that to the gearbox shaft adds to the tightness of bearing by making extra force to the sleeve.....and the sleeve is pressing against bearings race
Title: Re: M21 Clutch problems
Post by: nige63 on 05 Apr, 2024, 08:17
Quote from: neil1964 on 02 Apr, 2024, 15:55
Does your basket have protruding rivets at the back?
What happens if you leave all the clutch off except the hub and then tighten the nut up (ie is it a gearbox input/output shaft issue?

OK if i do this the shaft gets harder to turn even doing the nut up hand tight.
Title: Re: M21 Clutch problems
Post by: neil1964 on 08 Apr, 2024, 16:05
Check inside the right hand side of the gearbox that your mainshaft nut is tight (ie the mainshaft is pulled up hard against the inner cover (ie to the right). I presume that you are using a paper gasket between case and cover - not just RTV and you have a few thou of layshaft end float?  I'm not sure what the early boxes need but the s/a boxes say 10thou. 
But main thing is the nut under the kickstart ratchet that locates the mainshaft.
It sounds like it might be moving to the left and binding in the high gear sleeve?
Title: Re: M21 Clutch problems
Post by: nige63 on 22 Apr, 2024, 05:38
Hi Neil1964 sorry only just seen this post will check this. I have put the clutch back on and when i do up the clutch plates the back wheel becomes hard to turn by hand  :-\
Title: Re: M21 Clutch problems
Post by: neil1964 on 22 Apr, 2024, 07:28
We are assuming that your gearbox is assembled correctly and definitely in neutral.

Before you tighten the centre nut of the clutch hub it still spins.  Before, when you tightened the nut it locked up the mainshaft/output shaft (as if the clutch was biting and in gear).

Now it spins freely until you tension the clutch springs?  Correct?
Title: Re: M21 Clutch problems
Post by: nige63 on 22 Apr, 2024, 16:21
Hi Neil yes thats correct.
Title: Re: M21 Clutch problems
Post by: neil1964 on 22 Apr, 2024, 22:30
Some pictures of what you have and the order you have assembled might be beneficial now.

From your present predicament it sounds as if something in the gearbox is causing the input and output of the gearbox to lock up, other than  my suggestions it is difficult to know where to go in case you have a mismatch of parts (very easy on these due to some subtle variations).

In particlular have you read the thread I linked to?
Here is a point to be checked - position of the bearing outer race:
(https://www.bsaownersclub.co.uk/forum/proxy.php?request=http%3A%2F%2Fi1151.photobucket.com%2Falbums%2Fo626%2FClassicVehicleElectrics%2FClutchPlateClearance_zpsknxddlar.jpg&hash=eaf80c43b788c86c4ea197353421574144fcd4c1)
Title: Re: M21 Clutch problems
Post by: neil1964 on 22 Apr, 2024, 22:38
Also the pic below shows the correct orientation of the bearing cages to avoid binding
Top is correct, bottom pic incorrect:
(https://www.bsaownersclub.co.uk/forum/proxy.php?request=http%3A%2F%2Fi1151.photobucket.com%2Falbums%2Fo626%2FClassicVehicleElectrics%2FBalls_races_zpsmfbwpmak.jpg&hash=2e3303898878407846af3f6ba53e4eb954ae673d)
Title: Re: M21 Clutch problems
Post by: nige63 on 23 Apr, 2024, 13:01
Thanks Neil . Yes i read the thread and all seems correct on mine. Looks like I am going to do my first gear box strip down. Thanks for all you help and advice.