Commando Crankshaft

Previously wrote:

Does anyoneknow of any issues in usung a 750 Crankshaft in an 850 engine.

Looking in the workshop manual, the technical data does not seem to differ from the 750 or 850 and as the stroke is the same for both capacities I am assuming the 750 will be compatable with the 850 and visa versa.

The reason I'm asking is that the original crank is going to be too difficult / expensive to repair so I am contemplating bidding on a 750 crank on ebay which should work out a cheaper / quicker option, assuming I'm not outbid of course.

Send a brief email to Roger Myers Info@rgmmotors.co.uk, commandospecialist

You can put 750 crank in the 1973-74 850 jobs you will just have to make sure it is balanced for your heavier pistons. It's flywheel may also be a bit heavier. Most people think that the bigger Nortons had heavier flywheels, when in fact it is just the opposite. The first 650s had the heaviest, part of them went up between the piston at bdc. The 750 and later 650 flywheels were lighter and were refined through the years. The 850 flywheel was lightest of all, you will see this when you get your 750 crank. There is nothing wrong with any of the cranks though and for street riding any of the factory flywheels will work equally well.

The E-start crank is of course different than earlier cranks in a few ways.