BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: Grandad Russ on 25 Mar, 2022, 10:49

Title: A10 swingarm clutch pushrod length.
Post by: Grandad Russ on 25 Mar, 2022, 10:49
Morning all,could anyone tell me the correct length of an a10 swing arm clutch pushrod.
Ta.
Title: Re: A10 swingarm clutch pushrod length.
Post by: JulianS on 25 Mar, 2022, 11:13
Depends on what you have. According to my books, for swinging arm;

1954/55 part 29 3860 = 11 13/32 inches. 6 spring clutch.

1956 on part 42 3108 = 11 17/32 inches. 6 spring clutch.

4 spring clutch listed as part 65 3940 and 42 3274 = 11 7/8 inches.

Title: Re: A10 swingarm clutch pushrod length.
Post by: Grandad Russ on 25 Mar, 2022, 11:18
Yep,thought mine was a little short.1/4 of an inch.
An easy fix.
Thanks mate.
Title: Re: A10 swingarm clutch pushrod length.
Post by: OLDBEEZAGEEZER on 28 Mar, 2022, 17:58
Hi Julian

My A10 is 1959 S/A and I keep adjusting my clutch lever/cable/operating arm trying to get my clutch operating as I think it should. I have a CRM 4 spring clutch which is smooth as you like and easy to find neutral.

The problem I have is that with the 1/16" play at the lever, and the actuating arm parallel to the gearbox, the clutch disengages easily but the biting point is about 1/8" at the lever. If I slacken the actuating arm so that there is a bit more leeway for the biting point, the cable is slack in the actuating arm. If I take up the slack....I'm back to fiddling with the adjustments again. Round and round we go!

I cant make out whether the pushrod is too long or too short.

Given that I have a four spring clutch should the push rod be 11 7/8?
Title: Re: A10 swingarm clutch pushrod length.
Post by: JulianS on 28 Mar, 2022, 18:27
The exact length of the push rod is not that critical because of the adjustment available inside the oval gearbox  cover and also the cable adjuster.

If you have the SRM light allloy pressure plate there is the extra adjuster in the centre and the push rod length needs to cut as the instructions. .

Wear in the gearbox lever pivot and the handlebar lever pivot can cause problems.
Title: Re: A10 swingarm clutch pushrod length.
Post by: DAVE BRADY on 28 Mar, 2022, 18:36
Hi OLDBEEZAGEEZER,

I find on the A10 the lever on the gearbox should be parallel or perhaps a tad beyond to the gearbox joint when the clutch lever is pulled in.  This gives the best angle, 90º, for the operation of the clutch.  If you have the lever parallel when the lever is out the clutch will be more difficult to set up.

Dave.
Title: Re: A10 swingarm clutch pushrod length.
Post by: OLDBEEZAGEEZER on 28 Mar, 2022, 18:48
Thanks for the replies.

I didn't really want to take the chain case off again as I had set the adjuster as per SRM but if needs must..

Dave, I will try your suggestion but I thought the arm was supposed to be parallel to the gearbox joint when dis engaged.

I'm grateful for any suggestions so I'll keep on trying.

Alan
Title: Re: A10 swingarm clutch pushrod length.
Post by: DAVE BRADY on 28 Mar, 2022, 19:07
Hi Alan,

A photo of the arm with the handle bar clutch lever pulled fully in.  I would think that the arm to cable angle is pretty much 90º which I believe is optimum.

Dave.