Bearing Shim Drive Shift A7 1948

[namloop]

To my learned friends
I have reviewed a post where on rebuilds it is found the Bearing Shim on the drive side is missing.
Whilst called a shim it functions more as a seal preventing oil transfer.
It is an odd shape shim with two internal cutouts. Part numbers 67-349/67-1239.
A number of problems -
1/ I cannot find a supplier of this shim
2/ How essential is this shim - I thought it must since it was designed that way, but not according to other posts.
3/ Does it go between the main bearing and case or beneath the engine sprocket shim on the outside of the case?

My thanks again
Stephen
Gold Coast, Australia

[duTch]

 Hiya Stephen, I thought when I first obtained my engine, that it had one of those, but having used a LJ crank(the other one broke when I used it in the first bike), I've lost track of a few bits over the years, in some situations a similar part is called an 'oil slinger', maybe though it was in the M20, or something else I had at the time for a while?
 That's all I can do.
 Cheers duTch

 Ps Hows the Gbox selector happening (Back in it's home topic)?

[namloop]

Further to my enquiry
In the 1948 parts book it shows p/n 67-1239 as a regular looking shim
On the D'fly drawing it is shown with a ridge in the middle
Can anyone clarify?

Dutch - it is described more of a seal than a slinger!

[bsa-bill]

is there a bit of confusion here.
Steve are the posts you refer to (missing shim) refering to the shim between crank web and bearing - needed to obtain max side play of 3 thou, of course it is possible a shim is not required should the tolerance of bearing,crank and case thickness be enough - and so missing shim

http://www.nsamotorcycles.co.uk/24-2113-bsa-b31-b33-m20-m21-oil-flinger-3783-p.asp here is an oil flinger, but not for an A selling on Ebay as item No   270919685448

I'm not familiar with very early A's but could be you have a hybrid as it seems like singles had the flinger but not twins

[namloop]

No - the mysterious shim goes under (from what I am guessing) the main bearing on the other side away from the shims taking up any end play.
Again, although called a shim it is to stop oil passing through and more like a metal seal.
I phoned D'fly tonight and they did not stock the part as it was not on their sales list, the Gentleman advised it could be as other's have said, redundant and not required after all.
In the attached pic it is PN 67-1239
again my thanks
Stephen

[duTch]

 Yup- that's the bit I had in mind

[muskrat]

G'day Srep, you will need one as without it too much oil ends up in the primary. Sorry don't have a spare one of those.
Cheers

[RichardL]

Would this photo be helpful?

Richard L.

[namloop]

Excellent - now I can see it goes under the main bearing next to the case - would anyone know the outside diameter and inside diameter of the part? I may need to get one made.
Thanks Richard!

[duTch]

 Ok but the way I see it is that picture is a 49 on  model, given that the cam followers are in the barrel casting-you need '48 (long stroke?) ?
 Not saying it's not the same set-up though

[bsa-bill]

would anyone know the outside diameter and inside diameter of the part?

Not me but someone might know and as a similar bit is used on M, B and C's there could be a chance it's available - even if needs modified a bit

[trevinoz]

Stephen,
                    I think that the part you are seeking is a thin shim which acts as a chip guard.
It slips onto the shaft outboard of the bearing and is fitted before the assembly is fitted to the case.
The splined sleeve holds it tight against the bearing. There is a relief machined into the bearing housing to allow it to clear when the engine is spinning.
O.D. - 2.120", I.D. - 1.141", both approx, measured with electronic calipers.
It appears to be made from what is known as "pen steel", 0.005" thick.
The splined sleeve has minimal clearance to the case so maybe the engine designer optimistically hoped no oil would escape.
The next series engine has the slinger and a seal was fitted from 1954.
I found a sleeve with an oil scroll machined into it on the shelf, all others are plain.
I don't know what model it came from but may use it anyway.
As an after thought, maybe you could fit a sealed bearing with the inner seal removed.
Trev.

[namloop]

Hi Bill
Many thanks that at least proves there is one!!
I have tried the main outlets in UK,NZ and Austria that I normally buy from but none have the part in stock or a stockist so I may need to try what you have suggested with the sealed bearing and remove the inner seal??
Cheers
Stephen

[namloop]

Apologies Trev the thanks today were for you - Bill your thanks are for the previous day!

 

[Peter in Aus]

Hi I'm new to this forum but read with interest about this "seal  or shim" between the drive side engine bearing and the housing, I to agonised over this part and also could not get one any where. I did think of using a sealed bearing and taking out the one of the seals. on discussing this with a few friends they told me that the seals in these bearings won't hold oil, I had already bought one so tried it out, I removed one of the seals cleaned the grease out (bit surprised not much grease in it) and filled it with oil, they were right the oil run straight out nearly as quick as I put it in so gave that idea away!
The sleeve that I had was scrolled as shown in Trevs photo and the clearance between that and the housing was very close I didn't measure it but would only been about 3 to 5 tho.  also the gap between the bearing and the housing where the said shim/seal  would go was only about 5 to 10 tho. so I figured that if it was there it was not going to help much so put it all together.
It is up and running now and seem fine, I have kept a eye on it and have done about 700Ks the oil level is still the same in the primary chain case so keeping my fingers crossed.
Will keep you posted
Peter