Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board 1958 b33 alternator question

Picked up a 1958 alternator model b33 and it is missing all alternator and clutch parts. Clutch is a damper clutch (looks something like a b44)
Anyone have these parts used?
Is it possible to put bike back to generator ?

Thanks, Joe

The really hard to get parts for your bike are a good set of primary chain cases. If you are not doing a nut and bolt restoration any alternator off a '60s Brit bike can be made to work. The clutch is the same as that used in a Triumph pre-unit. There are many differences in the way the motor cases for your bike are machined as compared to those for a mag/dyno B33. Alternator electrics are more reliable (in my experience), I would build the bike as it is intended to be.

Hard part is locating parts..someone else posted that 4 spring Triumph clutches will work...I need fwd sprocket also..

I replaced the four spring cush drive clutch on my Triumph with the later 3 spring type. It’s stronger and takes more plates.

I don’t know how applicable this is to your bike.

Joe. To go to a generator you need to install the magneto (Magdyno) with a generator mounted on top of it.. I expect you have a little distributor with points in it mounted where the mag shaft would go into the timing case. Do your cases have the platform for a Magdyno mounting?

It should be way easier and cheaper to restore the alternator system than convert to the earlier system.

Gordo

look something like this ?
typical Lucas primary side stator , 4 spring clutch and dizzy in magneto hole .
... angled-flat area , under dizzy and carb would be the magneto platform .

alternator version uses different inner and outer primary cover ... and allows of bolt on alternator upgrades

I do have cases but nothing else..
Hopefully someone who is sitting on some usable Triumph spares can help out..
Thx,Joe

Hi Gordo,
Been a while..
Hope all is good..
Yes it has a pad but now that Triumph parts will work I will see about finding someone with spare Triumph preunit parts to help out with project.

Thx, Joe

Hi, thanks for sharing photo..
This seems to be the path...Triumph preunit clutch and gear .
Was this a 12v battery ignition system as delivered from.BSA?
Any tips on fwd primary set up? Are splines from Triumph similar for both crankshaft and transmission output shaft?
I will probably have to make spacers,slinger, studs,etc..
Thx,Joe

Joe: I think the engine sprocket you need is 42-0088 (19T). Someone must have one for you.

I would expect that it was a 6 volt battery ignition system in 1958 as the singles were 6 volt up to about 1966.

Gordo

Hi Joe,
The clutch shaft adaptor for the BSA gearbox is different to the Triumph part, The taper angle is different, also the BSA has the rear extension with scroll that sits into the sliding plate on the inner case..
Now comes the problem of which BSA adaptor you need ?? as there are several depths of the taper section of the adaptor
BSA twin adaptors will not sit far enough onto the shaft to permit chain alignment on a single, The part also changed if the bike had a fully enclosed rear chain case or not..
If you go to buy a new clutch kit make sure it is comprised of UK made parts, as the alternatives seem to be made of cheese!!!
SRM in Wales can I believe supply a correct fitting clutch kit..
I believeYou will have to try and find an original engine sprocket (42-0088)
https://www.vintage-motorcycle.com/en/parts/bsa-42/bsa-b31-33-engine-sprocket-alternator-mod-19t
https://mikesclassiccyclespares.com/product/42-0088/

You can access a parts book online at, https://www.baxtercyclebooks.com/FB/BSA_B_Group_B31_&_B33/index.html

John

Hi Gordo...
Am I right in assuming any preunit 650? Or is there a particular year?
Guess I can try on Triumph forum or ebay to find good usable parts.
Thanks for the time and help...
Joe

Hi John,
Thanks for all the info..
I have been using that parts book from baxters.
I figured there may be some difficulty trying to get sleeve adapter from gear box shaft to match Triumph clutch...
May be someone will know which part will work..
Thanks...Joe

Joe: I am not sure what you are asking about a pre unit 650 above.

Here is a source for an engine sprocket, they could have other bits you need.

https://mikesclassiccyclespares.com/product/42-0088/

Gordo

Hi Joe,
The problem with the shaft adaptor is that most sellers do not know what the part they offer will fit?? You will see "fits All 54-63" on their ads
You need to go to a seller (specialist) who knows the difference between the 4 or more outwardly identical parts
The dealers who specialise in Gold Star parts should know what you need, or as I suggested SRM
I wish you luck in finding good "used" clutch parts !!!
The Triumph clutch inner drum that incorporates a cush drive is what you need, I have never found a good secondhand one, when worn internally they cause all sorts of clutch issues, DAMHIK !!!

Changing the bike to 12 volt will make the wiring much simpler as you can do away with the troublesome combined lighting / charging / ignition switch..
Royal Enfield (2 wire) alternator / rotor and rectifier regulators might be a cheaper alternative to the replica Lucas parts. the modern stator will not match up with the old rotor..

John

What Royal enfield? 500 bullet or interceptor?
Thank you for help, info...

Hi Joe,
You would need the bits from the older 90's 350/500 Bullets (that look identical to the 50's Redditch models)

John