I have a 71 commando and this is proberly a dumb question, I need to know if the jug is sleaved. I had a rod let loose & broke the bottom portion of what appears to be a sleave. Can this be repaired or do I need another Jug?

The cylinder spigot hangs down inside the crank cases if it gets broken off, the barrels can be sleeved. I'd prefer finding used barrels that will take an over bore of +20 or +40. It's usually pretty easy to detect a sleeve inside the spigot they will usually not break at identical spots.

Thanks for the info. I have an 850 cylinder, will it bolt on to a 750 crankcase? Thanks in advance

Installing 850 barrels on 750 case can be done with some machining to open up the case a little bit. The bolt holes will line up...but you will need to change to 850 hardware to hold the barrels down. The balance will be off since you will run hewavy 850 pistons on a 750 crank balance. Then you need a 850 head cause a 750 head won't bolt on 850 barrels. It becomes more problematic than finding good used 750 barrels............

Thanks Dynodave for the info. With this info I'll be looking for a good 750 cylinder?