Triple gears in 750 ..... WTF?

chrisk

chrisk

Hero member
Location
Brisbane, Australia
Here's a strange one. Years ago I purchased a 750 motor in pieces. Red is working on it now and he tells me it has (until he sourced 750 ones for me) a triple selector drum, fitted in the case, and never removed or replaced by me, and layshaft. He tells me the 750 other half of the gearbox doesn't mesh with the triples.

To my knowledge this motor was a runner before doing cam bearings, stripped and sold, to me.

Q: Would this have ever worked in this format, perhaps it had a triples gears all the way through it???? Is it even possible????

Buggered if I know!  I can't see why it was done and leaves me scratching my head.

Red too has had to work this out at the customers expense!  :o Oops, that's me!
 
I can picture Red rubbing hands together with what passes for a smile right now, saying "finally, we can afford the rest of the bits for Max's Corvette muuaahahahaa"..... :D :D :D :D

 
difference in length of the mainshaft between a twin with no circlip provision and a triple with circlip provision means it fouls the clutch drum
not insurmountable with a lathe but it is a bit hard to remove the extra tooth from first gear, to make it go from 34 tooth to 33 tooth so it meshes with the mainshaft
that stuffed me, just could not work out how to do that

then there is the selector drum, machined scrolls are backwards and neutral detent is at opposite ends
was going to weld it up and remachine it but thought I'd chill and have a beer with Mark

twisted twins, aptly named

 
The triple selector drum should work OK in a twin, just need the triple selector mechanism to match.

The basic layout of both gearboxes is identical, as are the selector forks and the basic dimensions/spacing of the individual gears.  Only different gear ratios for some of the gears.

Using a triple 1st. layshaft gear with a twin 1st. mainshaft gear is a bit dodgy to say the least...

piet
 
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