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Post Info TOPIC: Engineering advice please?


Super Guru

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Engineering advice please?
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I stripped out a kickstart mechanism a long time ago that had damaged splines. The parts are all together waiting for a miracle "cure" and it was a miracle I found the tub of parts!

I know we have some engineers on the forum and would be grateful for some advice on whether the splines might be repairable and, if so, what would be the process?

A new shaft is £148 plus VAT bleh

Kickstart damaged shaft 001.jpg

Kickstart damaged shaft 002.jpg

Kickstart damaged shaft 003.jpg

Kickstart damaged shaft 004.jpg 

Brian



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I would say the only way to get it back to as new is to have it built up with weld and have the splines re-cut. if you can find some one to do it , i would suspect a new one would be cheaper. if I was stuck i would clean up the remaining splines with a thin grinding disk in a dremmel, making sure it was a good fit into a kickstart with good splines, then cross my fingers.

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Super Guru

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a new one would prob be as cheap as building that up
& re-cutting the spline...
For me to do that at work it would be $90 a hour..
prob 1.5 hours to do it...
welding / turning round / then setting up in
a deviding head to cut the spline in the mill...

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Brian,
I would agree that trying to build it up with weld, then machine it back and re-cut the splines would cost you more that buying a new one. Plus even if the cost was less, given the material that the shaft is made of, it would require a compatible welding rod, plus pre or post weld heat treatment. The chances of creating a 'stress riser' which would lead to a crack, at the end of the splined area are pretty good.

Rob

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pug


Guru

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LOL looks like Mr mole grip's had a bite on that. as said

a new one would prob be as cheap as building that up
& re-cutting the spline...
For me to do that at work it would be $90 a hour.. me about £45 an hour
prob 1.5 hours to do it... cant work that fast 2-2.5 hours
welding / turning round / then setting up in
a deviding head to cut the spline in the mill...

takes me an hour to set my mill up to do spline cut's and I don't like doing it an that's if I have a cutter to match if not then a cutter's going to cost £60-£80 just for the one job. so sorry Brian will stand back on this one and say get new. that said have fixed gear shaft's like it in the past build it all up with weld and made a new gear leaver to fit on with a taper cotter pin Chainwheel Screw. but im not putting my hand up for this job sorry mate

pug



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Hi Brian,
do you or a mate have a small Lathe?
You could mount a simple 60 degree thread cutter vertically and slide it sideways to refresh the splines.
since they are already cut it will not take a long time. Line each one and slide the carriage apron.

good luck :)


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Super Guru

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Thanks for the advice guys!

Might try the thread cutter trick Henry - got nothing to lose eh?

Brian



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Maybe use a cotter pin like on a traditional push bike crank?

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Super Guru

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Hi Paul

The cotter pin or roll pin options are on the table if I can't get the splines sorted wink



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Super Guru

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you could key it to the shaft....
it can be done with a hand drill useing a round key...
clamp the lever to the shaft..drill down the shaft/lever
and insert a round key the same size as the drill bit
& tighten the lever... just get it in the right place first time...

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Bikes... 06 TTR250 / 09 XT660R / 1977 Montesa Cota 348 MRR / 1979 Montesa H6 125 Enduro...

E-mail  xtpete1@gmail.com

pug


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Brian
Been looking in my big box of old mill cutters an yep I don't have a cutter to match. them splines was pressed into the shaft in the first place thing called rack rolling. if you can find. a nice man with a metal shaper he can just grind a cutter and clean them up an if 75% or more come good you would get away without welding [ ps I don't have a Shaper]

Martyn

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