109 snapped drive shaft
 

Messing around adjusting the carb on my 109 this evening, heard a thud.

http://i986.photobucket.com/albums/a...0409122005.jpg

Didn't know enough to pay attention and notice it was a home made shaft with a pretty poor welding job.
Looks like I'll have to find a new shaft before I finish tilling.

Weld too hot and crystalized? ( became brittle and snapped )

That's an easy fix.

The end of the shaft is supposed to have a 1/4" hardened pin crossways that rides in a slot in the coupler. Over time the pin wears a groove into the coupler and apparently a previous owner decided to just weld the shaft to the coupler. It's always fun fixing someone elses lazy fixes.

thats all Im finding on my 125 !!!!! cob job work all over it. but I think I got them all found and fixed. just put a cast fan and shroud back on it tonight when insalling the spring assist.

If the driveshaft was welded to the adapter coupler/hub that fastens to your engine, then you will need a new adapter coupler/hub too.

(I have the drive shaft and coupler/hub out of my 129, and replaced them with a double flex disk setup. But, my adapter coupler/hub has the problem that IHinIN mentioned.....hense the upgrade. Twice out was enough for me.)

The hub isn't even original, it's solid all the way around with no slot for a pin.
I took it to a machinist friend yesterday, and just got it back about an hour ago. He cut the welds then made a slightly larger shaft, milled down one end and pressed the hub on then welded it in place as well as the flex disk mount, then balanced it. He did it for free so I couldn't ask for more.
I'm assuming I can cut this new shaft near the hub and install another flex disk. Would there be any issues with that?

I hate to poop your party, but I'm pretty sure that having no movement there isn't a good thing.

I believe that having the shaft welded solid to the hub will either cause your flywheel cup to fail or cause the shaft/hub to fail again.

Someone please correct me if I'm looking at this wrong.

Yeah I figure that's why this one broke. I explained the pin and slot in the OEM hub to my friend, but he's Czech and thing's don't always cross over well.

What I want to know is would it be ok to cut this new shaft near the hub, take a bit off of it and weld mounts for a second flex disk? Or would the end of the shaft still have to have some motion in the hub?

There's no need to do any welding...all of the parts to add another flex coupling at the front are bolt (or pin) on.

Have a link for parts? I don't know anything about anything, but the mount for the flex joint on the hydro end of the shaft is welded on, so I figured a new flex joint would need welded as well.