A65 rebuild

[Gup holland]

Hello Guys, sorry to interrupt. I'm on a different level. I've got a65 casses from 63. Looks just like you with the right part nr on it. Loose stud alternator.
I'm running this for over 35 years now after restaration. Inside there is a 734 crank. (Wide one and balanced )
I'm trying to figure out how they did it.??  Because i have also a smaller crank wich used to match with the casses. How did they managed it. Have they machined the depth of the roller bearing . Can you measure the depth for me?  Then i have clue how its possible? So i can have a refferance.
Mine casses doesn't have a thrustwasher , just a roller bearing, 1 shim.
Don't know the history of the bike, bought it when i was 17 years old, now I'm 54.

Sorry for my odd english,  Greetz  alex

[Spaceman]

In answer to MITCHELL:

I bow to Bess's greater A65 knowledge and assume he's right about the LH crankcase case being for a ball bearing. I also assume the RH crankcase is designed for the later thrust washer although a close up picture of it and the timing side bush would be helpful confirmation. If both are correct then the cases appear to be mismatched. The consequence of this is that the roller bearing will sit 50 thou to the right of where it should be for a 1966 onwards engine (whose bearing mount was machined outwards by this amount) which probably means the crankshaft is a few 10's of thou too long to fit between the bearings.

However, the crankshaft was also heavily modified in the 1966 onwards engines. In the earlier engines, the crankshaft counterweights were the same thickness but, in the 1966 onward engines, the LH counterweight is 60 thou thicker. It would be interesting to know which crankshaft the engine is currently fitted with?

Assuming it's a later crankshaft, the potential solution to the present problem would be to mill out the roller bearing mount to move it outwards by 50 thou. However, before contemplating doing this, it would be worth measuring up the engine to work out what the current clearance actually is (assumed to be a negative value) and to confirm that the modification will work.

I would be happy to measure up the engine and have a closer look at what you've got. I know the Hollywood area south of Birmingham (I was born in King's Heath) and, if I can persuade my wife to make another visit to Birmingham city centre, I would be happy to pop in and collect the engine.

[Bess]

Hi,
    It seems you have an early ball bearing set of casings so no need for a thrust washer. It looks like you may have a later crank which could be the reason you're having an issue.

Can you check your crank, has it got a plug on either end of the sludge trap?

Could you also post an image of the crank in the same orientation I have posted and check the cases have a matching number stamped as image 2?

Best wishes...

[Bess]

Hi Gup,
           I have just checked the roller outer cage in the casing, when fitted it is flush with the casing therefore the measurement you want is 13/16".

However:

I "believe" to fit the later crank, the face of the LH case and the oil seal lip needs to be machined to allow the bearing to sit deeper in the primary drive side, making room for the wider crank. BSA also made some mods on the RH case and bush, to make way for the thrust washer.


Best wishes...

[Bess]

Hi,
     For anyone following this thread, the crank shim cups.

There is 1 for the ball bearing, 2 different available for the roller bearing (I did say 1 for each). The bearing inner races are now bigger and the bearing carries the same manufactures number. Care maybe needed, the new shim cup has a 65 thou bigger diameter to accommodate the different race. There has been problems where the shims in the cups are tearing, it maybe because the old smaller diameter shims are being used in the larger shim cup?

Best wishes...

[MITCHELL]

Hi Bess, the casing numbers match, if posted some photo's as requested including the old  and new bearings although they are different as in one ball the other roller  the actual width is the same when fitted in the case it stands proud on the inside by as much as a couple of millimetres. Cheers Dave.

[Bess]

Hi,
      Just check to see if the sludge trap has blanking plugs both sides of the crank.

If so, you have all the components for a ball bearing engine and if fitted correctly should spin freely. Worth checking the depth of the bearing recess, it should be 13/16".

Best wishes...

[MITCHELL]

Hi Bess, the sludge trap only has a screw cap on one end, measured the depth of the housing which is exactly 20mms  which according to the internet is slightly undersize  ( 13/16 =  20.63 mm)

[Gup holland]

Hi bess and mitchell, I'm following your discusion it does have a lot info for me. Bess, i measured the depth of the bearing casing ; 0,792"-  20,25 mm.
When the outer cage was still in i took Some measurements  see pic.  The outer cage wasn't flush with the case. Stands 0,157"- 0,4 mm out.  So it doesn't  seems like they machined the bearing depth?

My case doesn't hold a thrustwasher.  See pic.
The  Bush has a thin flange mine is 0,100"- 2,55 mm and stands about  0,003" - 0,1 mm above the case. I know there were 2 types off bushes,  did they do something on the timingside Perhaps?...
I,m very confused know, mitchell should have the same bearing depth as mine? If that is so, what happend.

Read already the CBS story about the differance of the cranks, small/wide.
Have a good +65 crank, 1 plug crank. Can put it in and i have to overcome 0,590"- 1,5 mm prox.
Self made thick shim for instance. The old TS Bush Can stay in, only needs to make bigger to +0,20."
The 734 crank is now over 0,50"
If Someone have a clue? Please react, I'm also on the dutch BSA forum, but it isn't that lively as here on your forum.

Best wishes from the metric side.

[MITCHELL]

Evening Spaceman, thanks so much for the offer but why on earth anyone would want to come to Birmingham for pleasure I have no idea, well see what transpires through this thread and poss chat later, incidentally where abouts are you? Dave.

[Bess]

Hi,
     Check which crank you have with these dimensions G and D:

[Gup holland]

Mitchell ansered my question already, Can you measure the  timing side Bush flange, is it the same as mine?  2,55 mm ?

Totally lost here now.

[Gup holland]

Thanks bess, gone look on the other crank wich type it is..The crank wich was in was stamped on the web 734.

Gr gup

[Bess]

Hi,
     The bearing recess of 20mm sounds okay it needs to be slightly shallow, ensuring the bearing is proud and the crank doesn't foul the casing.

Best wishes..

[MITCHELL]

Hi Bess / Yup. The mist clears.....  The measurements on my crank correspond to the post 66 crank, my bikes a 64 with I presume 64 cases. Yup the flange on my bush is approximately 2.5 mm..... Is there anyway this crank can be modified to fit,  maybe machining out the housing. 😞