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Repair on Dirtbike Output Shaft

Joined
Jul 27, 2012
Location
PA, USA
Hello,
I was given a gearbox output shaft from an old dirt bike. The chain sprocket chewed up the splines on the shaft as shown in the attached picture. Its interesting that it did this. I just have a Leeb hardness tester. testing the shaft vs the gear, the shaft, converted to Rc is about 60 and the gear measured around 45. Anyway, the part is no longer available.
Instead of trying to make an entire new shaft, I was thinking about TIG welding material into the missing spine area and then cleaning that up. I'm assuming this is most likely chromoly. Looking for recommendations on how to do this. Should I anneal it, repair and then re-harden? Re-hardening shouldn't hurt the material. The owner also wants to try and tap a bolt into the end and use that vs a simple E-clip to hold the gear in place. Not sure if I can drill and tap without softening it up some. Any feedback is appreciated!
 

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Anyway, the part is no longer available.
What does this mean? No longer available from the OEM? Or is this from a one-off, 1978 Honda works CR250? I have some bastard motorcycles and I think I could scare up an output shaft for every one of them if I had to.

Me suspects that someone could probably solve this on eBay for under $100 and seriously undervalues your time or has zero idea what that will realistically cost to fix.
 
What does this mean? No longer available from the OEM? Or is this from a one-off, 1978 Honda works CR250? I have some bastard motorcycles and I think I could scare up an output shaft for every one of them if I had to.

Me suspects that someone could probably solve this on eBay for under $100 and seriously undervalues your time or has zero idea what that will realistically cost to fI

What does this mean? No longer available from the OEM? Or is this from a one-off, 1978 Honda works CR250? I have some bastard motorcycles and I think I could scare up an output shaft for every one of them if I had to.

Me suspects that someone could probably solve this on eBay for under $100 and seriously undervalues your time or has zero idea what that will realistically cost to fix.
I was told its no longer available as a part. He found one on Ebay but said this is a known issue??? Don't know much more than that.
 
He said he couldn't get a new one anywhere. I'm guessing that meant OEM and aftermarket. Its an old Kawasaki bike.
John K. - That's what I was thinking. Would you use any particular filler or just the normal? I assume just normal ER70S is good enough.
EmGo - Thanks for the feedback on 8620 that just has a case hardening. If so, that makes it easier if my customer still wants to drill and tap.

I appreciate the info!
 
While back I had one like this ........apprentice signed up for a $3500 dirt bike loan .........engine gear stripped the spline after 31 days (30 day warranty).........shaft is part of flywheel assy ......$1100 part ,and on backorder.........I got it working again so apprentice can sell the bike to another sucker .............Nooo,its going ,he must flog the shit out of it for one more weekend .........gear fails again ,and the apprentices parents take me to the Small Claims Court ......will I be fixing any more bikes ?Noooooo.
 








 
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