A forum for owners of Yamaha TTR250 trail and enduro bikes!

TTRfan · Super Guru

Engineering advice please?

alanwebbo · Veteran Member

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.

petenz · Super Guru

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...

Raggis45 · Veteran Member

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

pug · Guru

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

Henry · Veteran Member

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 :)

TTRfan · Super Guru

Thanks for the advice guys!

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

Brian

Paul C · Veteran Member

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

TTRfan · Super Guru

Hi Paul

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

petenz · Super Guru

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...

pug · Guru

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