:)
Greetings. Just starting to reassemble A65 bottom end. Crank has just been reground and I've got about .040" end float and that seems a bit excessive. So back to the book which mentions a "shim cup"
Would someone kindly tell me exactly what it is and a picture if possible. I can understand it in general terms but not fully.
Mike 8) 8) 8)
They look like this although you should be able to get one in the UK.
https://www.classicbritishspares.com/products/bsa-crankshaft-roller-bearing-shim-cup-68-0638-71-3288-clip-retainer-rhp-a50-a65
The shims sit in the cup and the lip, in theory, stops bits of shim coming out shouldit break up. To complicate it there were 2 types, depending on the bearing used, see service bulletin below.
:) :)
Hi Julian.
Thanks a zillion
Mike
:)
Hi Next question: - I have two different manuals-- one shows a thrust washer on the drive side journal and the other doesn't. Which is correct or is it for different years. Confused or what .com
Mike 8) 8)
Hi Mike,
What year is your bike? I believe they fitted the thrust from 1966 (Engines from A65 -101, A50 -101).
Best wishes...
:) :)
Thanks for that. I actually meant the timing side but I guess you knew what I meant. Mine are 63 and 65. so I guess they didn't have them????
Mike 8) 8) 8)
Hi Mike,
No, your machines have a ball race on the drive side not a roller hence no end float.
Best wishes...
:)
Current situation is. I have ordered a shim cup from USA(Thanks Julian) £20 inclusive, very limited supply. These are the later type which are slightly greater diameter to go over the larger centre boss of the later bearings---the bearings are interchangeable. The difference in the centre boss OD is 4mm, but that is not measured with a micrometer.
Apparently although they are slightly too large these cups can be used with the older bearings because they will still hold the shims in place. I would have to think very carefully about it but would probably do it at a push, if it was that or nothing.
So now I just have to await the arrival.
Mike 8) 8) 8)
Hi Mike,
Are you sure the bearings are interchangeable?
I thought the ball bearing cannot slide horizontally whereas the roller can, hence the need for the timing side thrust washer. Maybe a ball bearing can be fitted to the later models?
Best wishes..
:) :)
Hi Bess
Yes, because I've got the later bearing now fitted to my 1963 engine. All the plans that I have viewed show shims. However as you say post 1966 they had the thrust bearing. To confirm, maybe you take a look at Julian's answer of a couple days ago. He posted the relevant service sheet.
I will keep you in the picture on this.
Mike 8) 8)
Hi Mike,
We might be at crossed purposes here. As the service sheet is 1972 I assumed the change was for that year not for the change from ball to roller bearings in 1966.
I thought when they changed from the ball bearing to roller bearings they added a trust washer to the timing side. I didn't realize you can change the pre 1966 to rollers without a thrust washer.
Best wishes...
:)
Hi Bess
All that I have done is changed the original worn ball bearing for the later one. There is a very definite grey area in my knowledge. I actually have no idea if its possible to interchange roller and ball. What you say about the dating is true but as I said the new bearing only has a different OD on the centre spool. The ID of the spool and the OD of the full circumference remains the same.
I'm going to dig around for answers although a lot of my current knowledge comes from recent speaky speak with SRM. I'm sure that there are a few unexplained ideas out in Beesa land that we have all held dear to over the years. AND the machines kept running>>>>>
Take care
Mike 8) 8) 8)