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Occasionally my 78 bonnie will drop to neutral while downshifting. Am i just between gears because when i shift back down it drops into the appropriate gear. Ive had the tranny apart last year during the rebuild and didnt see any odd wear. This only happens every once in a while, but it always seems to happen at a bad time.
 

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that's a very common complaint about the left hand shift Triumphs. (thanks D.O.T.),

I believe it has something to do with all the spline joints in the linkage going from the shifter on the left over to the gear selector on the right side.
I don't know what can be done to fix it but it happens a lot on the "7 speed Triumphs", ( 5 gears and 2 neutrals)
 

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Possibly a design fault, exacerbated by the design of the shifter cam. You see, when you shift, the cam moves the forks, which move the gears, which need to mesh. It's possible the dogs aren't in perfect order to mesh, which gives you a neutral.

The other part is that the shifter cam is a 'face cam' design, rather than the 'star wheel' design in current use near-universally. With a face cam, it is possible and easy to land 'inbetween gears' such that the mechanism will not move the shift drum further, thereby giving you a 'false' neutral. With a 'star wheel' shift cam it is not practically possible to halt the shift drum in such a way that the cam indexing will not move the drum further, thus completing a shift.

Best option: hold the shifter until the shift is completed. Call it an idiosyncracy of the older bikes.

Cosmo
 
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