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Discussion Starter #1
Inmates !
The gear box has always been a bit agricultural, also sometimes difficult to get neutral when you want it and sometimes providing false neutrals (between 4th,5th and 6th).
Due to aluminium contamination in the oil I decided to strip down the engine and found a couple of issues relating to the gearbox.
As it is an early bike, and the gear selector ‘star’ had been replaced under warranty – I know there are other improvement mod's that can be bought…however these won’t overcome these issues :-

First problem. One of the gear selector fork rollers, which runs in the slots of the selector drum, is too big ! 20191128_152105.jpg
The slot widths are 8.00mm wide (measured with vernier calipers).
The 'trapped' roller, in the picture, is slightly elliptical and measures 8.009-8.013mm (measured with micrometer) and must really affect the freedom of movement.
The other 2 rollers (there are three in total) both measure 7.995 or thereabouts (less than 8.000 anyway).
Question is ……. was it like this from new or has the roller grown, like rolling pastry with a rolling pin ???

Second problem is the bearing into which the selector drum fits – gear selector ‘star’ end of engine casing. This is very notchy and doesn’t rotate freely like a roller bearing should.
After tapping the bearing out of the engine casing, it rotates freely. I tried tapping the bearing back in, testing movement as I went, but it started to go notchy when only half way in. This is apparently a common problem when fitting thin bearings into overly tight holes.
This must have been like this from new !!
A new bearing (which had been in the freezer for several days) was gently tapped in and seems OK.
Just got to reassemble the engine now.
 
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