1975 ES crankcases

Hi All.
As far as i know you cannot fit the 850 ES crankshaft into the 750/early 850 crankcases.
The question is if you can fit the 750/early 850 crankshaft into the 850ES crankcases.
Thank you.
Piero

HelloPiero, yes you can , BUT , you must shim equally (on both side !) your crank with shims of 1.5mm.......as you crank is not large enough !

marinatlas said:

HelloPiero, yes you can , BUT , you must shim equally (on both side !) your crank with shims of 1.5mm.......as you crank is not large enough !

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I am sure Piero can make the crank fit inside the casing but will the outside fit? The protruding PTO shaft will be shorter and as the triplex chainwheel is running close to the inner primary case, the chain may be rubbing on the chaincase with this set-up. There could be problems at the timing side as well.

http://jerrydoe.com/norton-commando-mk3-rebuild/

Piero: If you contemplate fitting a Mk3 crankcase, bite the dust and go searching for the proper crankshaft. Mixing and matching parts usually brings a lot of problems in the long run.

-Knut

Works fine on a race bike with belt drive and no alternator, but not so simple for a street bike with conventional chain primary. And you will need to use compatible parts on the timing side.

Ken