Engine case number

[magicflem]

I have come across a right side case with the number 67-1088 cast in it. Can't seem to find it in my parts catalogues. Any help would be appreciated regards year, model etc.

[trevinoz]

The casting number is not a part number.
The closest is A7 RH case, 67-1087.

  Trev.

[trevinoz]

Further to this, after looking at several sets of cases, the RH side is numbered 67-1088 and the LH is 67-1086.
Same cases for A7 & A10.

                   Trev.

[bsa-bill]

As has been stated here before the part number is one less than the cast number, don't know if this holds true every time or not

[magicflem]

Thanks guys.
So I could use this rhs case with the A10 1962 left case that I have.
What are the thoughts on line boring etc to match un-matched cases? worth doing?

[Goldy]

The problem with unmatched cases is that as you say the bores need to be re aligned but you also have to match the cylinder base and the sump plate. A small amount taken of the face for the sump plate  would not cause any problems but machining the cylinder base would lower the barrels so I don,t know if it,s possible. Need to see if anyone has done this.

[muskrat]

It is possible, if a bit time consuming. I would use the RH case as the reference and machine the LH to suit. A horizontal borer would be my tool of choice. I don't think you would have to take more than 20 thou off the barrel base for even the worst mismatched cases. A thicker gasket or compression plate will take care of that.
On the other hand a set of cases went for $50 US on ebay the other day plus $150 postage to Oz would be cheaper than the machining bill.
Cheers

[muskrat]

PS, http://cgi.ebay.com.au/BSA-A10-CRANKCASE-SET-MATCHING-NUMBERS-/370503751998?pt=UK_Motorcycle_Parts&hash=item5643be993e

[magicflem]

In the "line bore" exercise would they add a weld inside the LH bearing and bush housing to reduce the id then line bore to match the RH case?

[muskrat]

With the cam bush housing a new bush could be made with an undersize ID and line reamed to size. With the main it could be tig welded or bored oversize and a bush made to shrink in then rebored. The reason I would do it all this way is to keep the relationship between the crank, idler and cam pinions. It's been a LONG time since I was a machinist making gearboxes for elevators.
Cheers

[magicflem]

Thankyou to you all.... I will let you know how I get on.