Help needed with e start on MK 3

Buy a heat gun . Pull both gearbox covers and strip down . Freeze the new roller layshaft bearing. Heat case at bearing point. Pull out old piece of poo poo bearing ,then drop in frozen new. Reassemble. Feel good.

nznorton said:

I have been going over my factory MK3 manual and correct me if I am wrong but it looks as though I will not need to remove the gearbox from the bike to replace this faulty lay shaft bearing,

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Yes, the bearing can be changed without removing the gearbox. The bearing may or may not be faulty, but it should be replaced if it is found to be a standard 6203 ball bearing.
How to: http://www.doov.com/apps/nortoncompanio ... s&Itemid=8

nznorton said:

is it the bearing listed in my parts manual as #040100, I see the numbers mentioned here on the forum are for original, #6203 and for the upgrade #6203TB ?

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The replacement bearing supplied by Andover Norton is part 067710 which is an NJ203 roller bearing, however the 6203TB ball bearing is an alternative.

http://www.nortonmotors.de/ANIL/Norton% ... 06&Part=12

nznorton said:

.. Can someone explain why the original bearing can lock up the back wheel and then come right again for the next few miles,

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The cage begins to break up, the balls bunch together and the layshaft moves out of alignment, eventually the balls fly out, which often wrecks the gearbox. However at this stage it isn't possible to say if the layshaft bearing was the cause of the wheel lock up? It could have been something in the primary drive?

dougmatson said:

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nznorton said:

I did read something about this problem years ago but I thought it had been sorted out for the MK3 models (I seem to have lost the artical)..

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Unfortunately not, as the factory started using a cheap Portuguese made FAG 6203 bearing which only made matters worse.

Thanks to all who have helped and given me such good advise with this bearing problem of mine..

I have been reading through all the valuable links posted and will give it the old college try over the next few months..
I will certainly get back to you all and let you know how I get on, although I am sure I will be contacting you guys sooner for advise as the job progress..

All the best from down under
Paul