I am trying to locate BSA part no 65 2539, which is a sleeve with internal & external broaching which fits on the primary chain side of the engine crank and allows the installation of a 2 lobe cush drive unit as opposed to the original 4 lobe unit. Any help would be appreciated.
Are you sure the sleeve is different. I don't remember changing it when I changed the sprocket on my M33 from 4 to 2 lobe. I will have to go to the garage and check.
Phil Pearson junior informs me thus!
I have just checked, you are right the four lobe sleeve has its grooves closer together. Make sure that the sleeve is for the singles. I think the ones for the A type engines have a slightly larger hole.
Well, I suppose you would expect Phil Pearson to be clued up on the subject, I am another matter. Anyway, Edie, thank you for checking it out. Incidentally, you are spot on with your warning... the early A series are different and they can be identified by a slight groove running around one end of the sleeve! I have finally sourced one from George Prew, just hope it is the correct one - it was hellish expensive!
Wll the price is no surprise. At least you are moving forward.
Yes, price of stuff these days! I remember, just, when Pride an Clarke were selling new M21 engines for £25. . .
I loved browsing in Pride and Clarks, not far from where I lived at the time.
The sleeve has arrived and... it has a slight groove running around the outside of the shoulder at one end! I don't believe it! I am concerned that it is the wrong one!
Try it first before condemning it. Sometime you need to leave out the spacer that that sits against the bearing. I have noticed that there is many variations on the sleeve.
Could anyone tell me if the cush drive assemblies on the swinging arm B31/33 models are the same as the A7/10 models other than the amount of teeth on the primary sprocket?
No not the same, cush bearing to crankshaft spline is different and there are several different but similar versions of the cush bearings.
Thank you Julian..(and Idie)
Panic over, I thought the sleeves with the faint groove around one end was for the A series wherein it is actually the reverse. I now have a two cam cush drive on my bike (Not to mention an electric start kit) and everything is good. Incidentally, the engine sprocket was discovered to have 22 teeth (I thought 1st gear was a bit high) and it now has 21 teeth which makes it much easier to get going. I have now learned that my machine has Gold Star forks & 8" front brake, an A series rear sprocket and a non BSA clutch - it really is a bitsa!
You have an electric start kit for a B33 with a steel primary chain case? Who made it?
No Mate, It's a bitza - The primary chain case is the later aluminium type, the foot rest brackets have been changed to suit, have now discovered the dynamo isn't charging! Could be a problem as electric starting tends to knock the battery about a bit but fortunately there is a charging plug connected directly to the battery and located in an accessible position just tucked ion under the seat. Gives me a breathing space. There was a slight problem when a crankcase breather was discovered between the primary chaincase and the crankcase just where the gubbins for the starter motor needs to be located. Went out on it yesterday, did about 80 miles (forgot to check the speedo prior to departure) and everything was good apart from an oil leak which has materialised somewhere in the head area.
Interesting that you have the later case fitted. If you ave Pearsons electric starter. The smallest engine sprocket is a 21 which is 2 teeth higher than standard. You will need to drop the size of gearbox sprocket then the speedo will run fast as the layshaft that drives the speedo will spin faster so the speedo will need re-calibrating. Have played this game.
The speedo is a reconditiponed unit and when it was fitted to the bike the engine sprocket had 22 teeth. It was very high geared which was actually only noticeable when starting off. It seemed quite happy at 70 and strange to relate, when I took it out yesterday it cruised along at 70 and sounded sweet and unstressed. Having said that, and read your post, it was probably doing quite a bit less than 70 given that one tooth difference on the engine sprocket is equal to 2 teeth on the rear sprocket! (I believe)
If you have a Pearson electric start the engine sprocket will be a double one. One for the primary drive and a narrow one for the starter drive. Your indicated speed was most likely correct as engine sprocket size will not alter the speedo. Only changing the gearbox sprocket or that on the rear wheel will alter the speedo reading.
You are correct Idie, although the sprockets are not double as in joined together, but there are two of them and the inner one connects to a secondary sprocket which then drives a shaft through the centre of the inner chain case where there is another sprocket which then drives the starter motor which is located under the engine/gearbox ass. It was a surprise to me as I was under the impression that the starter motor was inside the chaincase. A cautionary note is that because the starter protrudes below the bottom of the engine, care is required when loading the bike into a van - we had to physically lift the back end to avoid scraping/knocking the said motor where the ramp met the floor of the van!. Thank you for pointing out that changing the front sprocket does not affect the speedo calibration as I had imagined.