AJS & Matchless Owners Club

'Ive got two sets of twin cases, un-useable for various reasons but I've noticed they dont have matching numbers or marks, yet I know they came off intact bikes.

Does this mean AMC cases were so well machined that lefts and rights can be swapped for twins, as long as the part numbers of the halves match? (there are many small variations I know)

I would have thought not, inless very careful measurement is made in an engineering shop of the truth of the line through both main bearings.

But maybe not..hope this is not a wholly ignorant question.

its not unusual to find crankcases mixed , and i believe they were not line bored and available as separate halves . certainly if you check your spares list then you can see option of purchasing complete with studs , bushes etc. or separate halves

After I sold my G9, the purchaser found vibration problems were caused by a minute mismatch between crankcase halves.
So perhaps it does matter.

as you can see on the singles they are machined and finished as halves
http://archives.jampot.dk/promotional/C ... _Cycle.jpg

This is tue G80, but I can't find matching numbers on the twins?????

One local engineer in Kenya suggested I sleeve the drive side bearing recess with a generous sleeve in alloy, then line-bore back to size using the timing side as the reference....even if it ca,e out slightly eccentric to the sleeve, the inside bore would be true to then fit the main bearing outer.