55 Golden Flash Primary Alighnmet Problem

[RAC5558]

For HTH,

Can you tell me about how much difference there is between the single cylinder clutch adapter and that of the twins as far as how much difference there is in the resulting clutch location relative to the gearbox?

Richard

[BSA_54A10]

The tapers on the main shafts are all the same.
The clutch centers , the bit that goes on the main shaft with a tapered hole in it are different.
Oddly enough BSA did not give them different part numbers.
The hole is simply deeper on some than others as such a bigger hole will go further down the main shaft and thus sit closer to the gearbox.
I have at least 6 different ones for 6 spring clutches.
I found out this the hard way after I fitted one that in looked "better" condition only to find the sprocket on the clutch drum worn razor thin in about 10,000 miles.

[chaterlea25]

Hi RAC

HTH = hope this helps 

I figure the different adaptors vary how far the adaptor fits on by up to about 5mm (3/16 in old money)

Was there selective assembly on the production line???
Nearly every adaptor I have tried is different??

BEWARE  of new Pattern 6 spring adaptors they are too small on the outer diamater for the inner clutch bearing ???? ???? ????
The suppliers arnt arsed to send them back and complain to the manufacturers 

John O R

[bsa-bill]

HI ATC

The spacer protrudes beyond the face of the crankcase bearing boss about 0.080 inches.

putting my motor together and noticed the spacer protrudes at least as much if not a bit more than 0.80 " and my clutch aligns ok.

so maybe that end is right

[RAC5558]

Again, thanks so much for the input.  Between these reponses to my problem and my recent inspection of another local A10 engine with the cush drive assembly in place, I am convinced that the cush drive installation on my engine is OK with the possible exception of not enough spring compression.  Therefore, it seems that the problem lies at the clutch end.  Besides the variation in the tapered bore of the clutch hubs, I can visualize other possible culprits.

Namely:
1.  Bent transmission mounting plates.
2.  Sprung frame or manufacturing variations in the relative locations of the forward engine mounting lugs and the frame lugs to the rear that locate the transmission mounting plates.  A quick eye-baling of the mounting plates and frame tubes didn't reveal any obvious distortions or damage.

I don't know how likely either of these possibilities can be, but there seems that little can be done about it if one of these are causing the mis-alignment.  However, it would seem that if manufacturing variations were a problem, BSA would have provided a means of accomodating the variations by providing for the use of shims that would allow adjustments in or out and to a greater degree than the few thou. adjustment by shims behind the cush drive.  Perhaps, as suggested above, they used selective installatioin of varios clutch hubs.

RAC

[trevinoz]

RAC,
            Could you post a picture of your clutch centre?
The twin type is different to the single and is readily identifiable.

  Trev.

[RAC5558]

I haven't yet located my puller.  It is about 110 F in my tin shop at floor level and the puller is probably stored away in the loft where it is around 120 F.  I will look for it before sunrise tomorrow and see what turns up.  If I can't locate it I'll have to make another one.  Is the difference in the hubs something that will be obvious from photos?

RAC 

[Topdad]

Good morning RAC, Whereabouts are you located ? I've got a couple of clutch centres and would could send 'em if you think they would be of help, if you're close enough you would be welcome to have a look over mine , you'll probably be in Oz now but if UK based I'm in merseyside. I know they are not standard as another guy tried them and they were to big and to small respectively,so you'd be welcome to see if they could fit your mainshaft . By the way re the comments about selective assembly, don't forget one of the many insults layed at our beloved marque was that BSA STOOD FOR " A  Bit Stuck Anywhere"  I of course don't believe that to be true  !!   ................

[muskrat]

You mean like this topdad ! but after an hour in the saddle it's bl@@dy sore idiot !!
Cheers

[Topdad]

Hi Muskrat,  that was the standard one from the Trumpet riders, but like you I don't care ,I just love 'em faults an'
 all . How you doing by the way since your spill. hope you're feeling better best wishes Bob.

[RichardL]

Musky,

I hope you don't find this funny (it's not that funny, really), as laughter probably hurts with broken ribs and a punctured lung, but Bob's "Bit" and your "Bits" give two completely different meanings, don't you think? 

Anyway, also hope you are saying "Bye, Sores & Aches."

Richard L.

[muskrat]

Thanks fellas, wife thinks I'm mad, went back to work (floorsanding & polishing) Tuesday. Light duties (no such thing). Setting up a mirror so I can pull the stitches out (drain hole for lung). Hope to throw a leg over the bike on Sunday weather permitting.
Cheers

[bsa-bill]

Musky - she's probably right

Take it easy though, I recall being being off with a bad back (was kidney stone) went back to work and the manager sent me digging holes with a windy pick  , would like to say he went down in my estimation, but he was already as low as he could get, he still comes and speaks when he's wanting something

[RAC5558]

TopDad, I'm not located in Oz, but right next door in Ok (Oklahama, Central USA).  I really appreciate your most generous offer, however.  As for as the "BSA" translation; after 55 years it is not surprising to find bits where they were never ment to be.  I know some of my parts have moved about over the last 3 score years including some ribs and a hole in a lung that didn't belong there.

As for the clutch alignment, I have a late A10 four spring clutch, hub and matching (?) cush drive on the way.  Before I worry with this six spring set-up further, I am going to see how the four spring lines up.

I am most grateful for the input from all you guys.  You have steered me to what is, hopefully, a better rig.

RAC

[BSARoadRocket]

Assuming your frame and engine plates are straight and assembled correctly your alignment problem is that you are running a B33 or Gold Star clutch center.  I've experienced this problem myself  where the engine sprocket sticks out further than the clutch sprocket.   Jim Hunter (the old BSA Gold Star racer from Southern CA) explained to me that the single and the twin used different clutch centers and showed me an example of each.  Some people will call the clutch center the clutch adapter, basically it's the first lump of metal that goes on the mainshaft. 

Oddly sellers of new reproduction/pattern 4 spring clutch centers to use the 4 spring Triumph clutch on a BSA never specify if the part is for a single or a twin.  Since BSA made a different 6 spring clutch center for the twin and single it is only logical that there should also be two different versions of the 4 spring clutch center but I don't know.

As far as the nut on the end of the crank (the odd one with the 4 notches in it)  that holds your cush drive spring in place, it needs to be tightened all the way down right up against the inner sleeve.  If it is not tight the inner roller bearing race could spin on the crank.