2 version of clutch parts

[Devlin]

BSA A7 1949 plunger
Looking at the parts  list and pictures there are  two variations of assemblies and as I have no "old" parts to reference I am at a loss and given that I need everything that goes on the output shaft will I have a problem
Devlin

[Swarfcut]

 Devlin   The crankshaft splines and gearbox mainshaft remained the same from start to finish on rigid and plunger bikes. The drive sleeve for the  early engine differs slightly from later models in that this engine has no crank oilseal and the sleeve has a larger diameter flange than the later version. 67 2053 is the part you want, and is fitted to all engines prior to 1953 model year, when the seal was introduced. From your earlier posts and pictures I assume these parts are correctly fitted as found. You just need a complete clutch and primary chain.

 These are common to all years and models of rigid and plunger bikes. Clutch thrust washer which you already have 67 3276/7/8 comes in three different thicknesses to aid primary chain alignment.

 When you say two variations of assemblies I reckon you are referring to the two versions of the so called 6 spring clutch. Single roller chain type used on Swing Arm bikes, and the duplex chain Rigid/Plunger type. The former will not fit,  it's completely different.

 ebay sellers lump the two as "BSA 6 Spring Clutch" hence the confusion for the unwary

 My Parts Book 1954/1957 has the clutch you need illustrated on Page 24 "A Group Plunger Frame".

 Plenty on the Forum about this primary drive, Plunger Models have had extensive coverage to date and posts and pictures also apply to  rigid  framed versions.

 Swarfy

[Devlin]

Could you send me a link to your parts book, I have had a trawl through the appropriate section but I cant find it
Devlin

[Swarfcut]

 Here's a link to our Forum Literature Section

https://www.a7a10.net/forum/doc/parts/A7_A10_1954_to_1957_Spares.pdf

 This parts book also contains the later S/A models.

 Swarfy

[Devlin]

Thanks again, Looks like I need everything from 8 to 23 , to begin with anyway,Rather than trawl the various suppliers shops ,if possible can you suggest a place that will have it all I have a feeling getting parts from various sources I run the risk of mismatching parts
Devlin

[Devlin]

Despite my best efforts I still connot source the correct parts, the pics show what I have got so far both claiming to be for ridged A7  another 2 attempts at other parts from ebay sellers never turned up although I see one up for sale again, I now doubt very much the knowledge of these sellers and suspect they are chancers I hope someone can throw some light on this
Devlin

[RDfella]

2nd pic - the clutch centre on the left is plunger type, the one on the right is from a BSA single or later A series with swing arm (gearbox separate from engine).

[Devlin]

Thanks, the one on the left is what I think is correct however, the spines do not engage, looks like a trip to the next normous event is on the cards, the biggest issue is the previous owner "lost" the box of parts he removed
D   

[Swarfcut]

     We can see who did their homework, eh, RD.

    Side by side there is no mistaking the substantial centre of the rigid/plunger clutch, along with its splined boss. Looks the right part,  a reasonable buy and  should slide easily onto the gearbox mainshaft, so something not quite right.

     Sell that other puny offering, it is the type found on S/A bikes, plus similar B and M ranges with the taper fit adaptor for the gearbox mainshaft. That pressed steel design comes in three different heights, to suit lower powered machines requiring less clutch plates. I made a dig at RGS owners finding an M series clutch under the primary cover..... That centre also suffers from loose spring mounts, so getting the clutch apart can be an entertainment.

 Plunger chainwheel has a duplex chain, one size fits all from start to finish. All clutches suffer notching of the driving fingers, so obviously choose the best you can find. Only used on this chainwheel, note the threaded support bolts that fix the clutch cover, often missing or abused on used examples. Also look for a good track for the rollers.

 Swarfy.

[Devlin]

It's going to be a challenge by the looks of it.
Thanks

[muskrat]

G'day Devlin.
Here you go https://tinyurl.com/yc53ew75 a good clean up and new friction plates, springs and cover.
Cheers

[Devlin]

Moving forward on the parts hunt, however bearing race 65-3912 is proving illusive, any ideas where I might find the diamensions of this as it looks well within the ability of a machine shop
Devlin

[Swarfcut]

 Devlin, which race is this? Are you sure? That part number does not feature in any of the post 1949 plunger parts books I have. No wonder it's playing hard to get! 

 But...it is part of the S/A  post 1954 6 Spring Clutch, which is not the clutch you want.

 Swarfy.

[Devlin]

Its number 37  on the parts diagram on page 17 of the BSa parts manual number 15 looks like a bearing race but descibed as a retainer
D

[muskrat]

G'day Devlin.
I have the same results as Swarfy.
If it's the outer race that's in the basket, good luck. It's not listed as a replacement part. In the olde days you' just order a new basket!
Is it wobble with the basket your worried about? They all have a bit of that. The best I've been able to do is new rollers and thrust washer 67-3276.
I had thought about getting 1 thou oversize rollers and grinding the bearing race to suit. I don't have a spare to play with.
Cheers