gear change spline size (2020)

850commando · May 7, 2020

so i need some basic information, search hasn't found me an answer yet. what is the size of the spline on 74 commando gearchange shaft?

and what is the proper way to describe it?

thanks

dobba99 · May 9, 2020

850commando said:
so i need some basic information, search hasn't found me an answer yet. what is the size of the spline on 74 commando gearchange shaft?

and what is the proper way to describe it?

thanks

Good question, I measured up a spare gearchange shaft (I think from a lightweight twin) that has the same spline size as my Mk3 850, so i could manufacture a rearset lever. The photo shows various different levers and the shaft they were cut to fit.
The shaft has 36 splines that have 80 degrees between the flanks and measures up at 0.623" in diameter.

850commando · May 9, 2020

thanks. since posting the request for info, i used my caliper to measure the dia at ~0.625' and did a count on half the splines, also getting 36. so is this then specified as 5/8" x 36 spline?

my reason for asking ; i want to replace the dunstall linkage with just a reverse lever, which in combination with the rearset pegs would give 1 down 3 up shifting.

.c. · Apr 21, 2022

850commando said:
thanks. since posting the request for info, i used my caliper to measure the dia at ~0.625' and did a count on half the splines, also getting 36. so is this then specified as 5/8" x 36 spline?

my reason for asking ; i want to replace the dunstall linkage with just a reverse lever, which in combination with the rearset pegs would give 1 down 3 up shifting.

Did you ever find the correct term for this spline? I'm looking for a supplier for a broaching tool.

c

Stephen Hill · Apr 21, 2022

Just guessing, but I kind of doubt you will find a broach for that spline.
It would have to be cut with a single point tool. Using a shaper. And a rotary table.
It would be way easier to start with a stock shifter lever and modify it.

Shelby-Right · Apr 23, 2022

Or if you have time , make a accurate plate marked , and drilled for a pin to locate , mount to lathe spindle set tool and use cross slide and hand wheel to do each spline , they are only fine splines , otherwise some mills have an attachment with a small clapper box use with dividing head .

850commando · Apr 23, 2022

no i haven't gotten to this yet, i don't have the tools to maek one so was having to hit up my friendly machine shop..

gear change spline size (2020)

850commando

dobba99

850commando

.c.

Stephen Hill

Shelby-Right

850commando

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