2 version of clutch parts

[Devlin]

I am starting to think I have some sort of hybrid or franenstien bitsa, here is how it seems, I have a duplex crank sprocket which would suggest its a 6 spring set up, however the gearbox input shaft end is splined for 4 spring centre job, I sent for N0 40 and 62on the diagram  part numbers 42 3107 and 42 3236 respectively to help me make sense of it all  but they seem to be again for clutch centre 61 part 42 3220,  is it possible the gearbox has been changed although I cant imagine it, I got the old duplex chain with the bike would a duplex chain actually work on a single clutch sprocket from a duplex crank hope someone can help
Devlin

[JulianS]

That shaft looks like a plunger/rigid shaft splined to take the plunger/rigid 6 spring clutch.

The part numbers you mention are both for the 6 spring swinging arm clutch.

Below is from the 1949-53 parts book showing the plunger/rigid clutch.

You can access all the A7/A10 parts books on this forum.

https://www.a7a10.net/forum/index.php?topic=12471.0

[Devlin]

Thanks, I can see where I was going wrong, looking at the wrong model years making sense now
Devlin

[Swarfcut]

  Devlin  This saga is going round in circles and cash is flying the wrong way.

 Time for a reality check.

 Julian has posted a couple of very helpful sources which will assist to put matters right. Look for Plunger Clutch. These models feature a bolted on gearbox with a slipper adjustment for the primary chain.

 Your bike has a splined gearbox mainshaft, the clutch centre slides directly onto this shaft, abuts against that circular thrust washer, and is secured with a nut and tab washer. From your earlier posts you have already got this clutch centre. All the other parts you have bought are from the later model, the S/A versions with a taper on the gearbox mainshaft. None of them will fit. You need the clutch parts from the Rigid & Plunger framed bikes, all of which interchange from the 1946 Longstroke to the last ones in 1956.


 You mentioned your plunger clutch centre did not fit, so a little more investigation is required, that gearbox shaft looks short, hope it is just the camera angle. Behind that thrust washer there should be two half round parts which make a support ring (67 3251) which fits in a machined groove on the shaft.

Swarfy.

[Devlin]

Thanks Swarfy, I cleaned up the centre and tried tapping it on without success, I will have time this week end to have a look at the situation, the shaft looks short as in that pic I think the washer is a bit down the shaft and I cannot remember any thing behind it,I have searched the part numbers from the linked parts manual from Julian with limited success but I have not had a real search as yet, worse case scenario is there another model year I can use or indeed any alternative complete set up I can use
D 

[Swarfcut]

 Devlin. I've just had a look back thro' all your posts and came across pictures of the primary drive posted by esteemed Forum Member Minto. These include a good pic of the gearbox mainshaft with the split collar/support ring in place along with views of the completely assembled clutch. I also found one of my own earlier posts detailing what looks to be an incorrectly assembled chain tensioner.

 Splines on that shaft are 21mm long, from the threaded end to the end of the splines it's 34mm and I would expect around 40mm of shaft to protrude into the primary case. The shaft should have no end float and next to no up and down/fore & aft movement. In neutral it should turn silently. Clicks and ticks are likely to be the kicker return spring catching on the kickstart ratchet...an easy fix.

 Just to confirm, does this engine have a single rocker box or two separate ones?   Stick with the BSA Parts Catalogue 1949-1953 A MODELS Twin Cylinder to avoid confusion with later variants. Worth punting on a cheap reprint, I got mine from Ebay seller "Ekka's Mecca", a spiral bound offering with good quality print.

 Swarfy

[Devlin]

Yes 2 rocker covers,

[Devlin]

I cant get the PM to Swarfy so hope you see this post instead PIC of Rocker coveer

[RDfella]

That cush drive looks all wrong - a 4 lobe sprocket with a 2 lobe cam?

[Swarfcut]

   There you are folks, the elusive Longstroke in all it's glory. That looks fine to me, the cylinder head even has the two  vertical fins adjacent to the spark plus.....not many of these fins survive.

 Looks to have the later E3L dynamo poking thro' the front engine mount. What a find!!! Cush drive also looks to be the right one, correctly set up and  relatively unmolested by the traditional use of the big hammer. In these enlightened times get the proper tool. Peugeot ball joint socket rumoured to fit....

 Swarfy
 
Mod add: the tool  https://tinyurl.com/yazushx5

[Devlin]

So far so good got the hub and chainwheel just plates, springs,cups and nuts to get however where does the  20 odd roller bearings go back of the chainwheel for sure but what acts as an inner race looking at the diagram I cant see what else is missing
Devlin

[muskrat]

G'day Devlin.
The rollers go between the chainwheel and center (hub). The bit that sticks out at the back of the center is the inner race and their held in by the thrust washer when it's all on the shaft.
I put the center in the chainwheel, insert the rollers, smear a bit of grease to hold'em in and offer it all up to the shaft.
Cheers

[Devlin]

I have a question re the spit collects,apparently they come as a one piece new and are spilt in two so does that mean they are cast not machined, there seems to be shortage of these and thought I could have them turned by a machinist but perhaps this would mean they would wear quite quickly, thoughts anyone
Devlin

[RDfella]

Should be no 'wear' as there's no movement. They need to be hard (because the lip they sit on is marginal) but not too brittle. Bit of heat treatment of appropriate material after turning up a ring and splitting into two perhaps.

[Devlin]

Does anyone have the dimensions of the collet ,long shot I am sure, I can get the inner diameter and thickness from the shaft but that's all ...unless
Devlin