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850 crankshaft flywheel, refitting cranks


My 850 Commando came to me as a load of bits with the crankshaft disassembled. All three components check out as correct but which side of the flywheel does each crank go? The flywheel has a very discernible difference in the lip above each edge nearest to where the cranks affix. I have looked at parts books, Norman Whites superb restoration book and all over the net but seem to only find reference to marking the components so that they are put back as originally assembled. Clear this is not much good to me. Any knowledge out there please?

Flywheel pics attached.

Thanks in advance, 



You make marks before disassembly which look to be missing, the last time I came across this I carefully looked at the marks on the flywheel flange and crank ends and was able to match them as the oil burnt stains were mirror images. Before you do that look for a T on the outer edge of the flywheel and that should be the timing side.


There was a thread on access Norton with pics of cranks trying to work out differences to see if the flywheel was always one way, the cast surfaces were all over the place in relation to the machined datum points. So looking at pics leads nowhere.


The early Dominator engines had a T, S or Z stamped on the edge of the flywheel.  As a rule this was usually found on the Timing side of the assembled crankshaft. Likewise, these Norton chunks generally came with a casting number which also usually faced the Timing side.  See Photos.

Back in the 1970s the Norton factory was boasting that their modern machining methods were so good parts such as crankcase halves no longer needed to be matched, Silicone Goo was replacing thick gaskets and the crankshaft flywheel could face either side of the engine.

In my experience, parts distort with aging and dismantled chunks need rebuilding with matching faces. The latter always seen as good engineering practise.


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