Kick start lever

- J
- John
  
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posted
15 years ago

Mon, Dec 22, 2008 12:59 PM

I have to make a new kick start lever for my bike. The lever will be basically a shaft with a 1/2" dia. 1" long parallel section to a shoulder then tapered from 3/4" down to 1/2" over an 8" length then parallel for 3". The shaft will be heated and bent at the point where the taper becomes the 3" section. The 1" parallel section will be pressed and welded into a boss.

For material I am considering using a half shaft from a Citroen GS I have had 'in stock' for many years. It is very material tough when I did a test turn.

Most motorcycle kick start levers that I've looked at appear to be forged, presumably so the grain of the metal is in the right plane. Normally they don't bend when used!

The question before I spend ages making this is, will the lever made out of half shaft material and after it has been heated and welded, be likely to bend when it is used?

Thanks in anticipation.

John

- A
- Austin Shackles
  
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posted
15 years ago

Mon, Dec 22, 2008 4:29 PM

On or around Mon, 22 Dec 2008 04:59:43 -0800 (PST), John enlightened us thusly:

My thoughts:

The half-shaft is likely some decent-quality steel, as you surmise. Welding it might make it brittle adjacent to the weld, if so, you'd have to heat the whole thing once made to anneal it and then (optionally) re-harden as you choose.

Half-shafts and their ilk generally having splines at the ends, they're going to be heat-treatable (unless, of course, it was case-hardened, but I think that unlikely.)

- N
- Nick Mueller
  
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posted
15 years ago

Mon, Dec 22, 2008 10:11 PM

If you look at real bikes (whatever that is), they do have kick start levers made out of aluminium (forged). And they also don't break.

Re steel: I cut the lever of my KTM because it was way too long and always stuck in the mud when the damned carb once more failed. This one was tempered (and I ruined a blade of a cold saw, fortunately not mine). I simply welded it back together without any heat treatment and ignoring the assumed carbon content in the steel. It didn't break. Then I fitted an Mikuni carb. :-)

Nick