2012 Te310 Doesn't Start (only Backfires When Kicked)

Last November my 2012 TE310 broke down on a dualsport ride. I put the starter assembly and ring gear in the bike (which was removed by the previous owner) before the ride, and when I took the bike apart when I got it home I found that the one way bearing on the ring gear had come apart, which locked up the engine and melted the stator. After removing all of the starter parts, replacing the stator and changing the oil I got it to run briefly, but it didn't run as well as it did before, I wrote that off as an effect of the cold weather as I did this in January in my unheated workshop. When the snow melted I got it to start and run long enough to go for a short ride, after riding a half mile down the road it bogged down and died on me. After that all it would do is back fire when I kick it over.

After that happened I had a guy I know who works at a ktm dealer work on it for me. I would have taken it to a husky dealer but there aren't any near where I live. He couldn't fix it, all he could figure out was that the spark was weak, and that it's not an injector problem because he cleaned it. But when I tested the spark myself, the bulb on the tester lit up. After that I checked all of the connections and made sure the valves are in spec. My only other idea is that the key may have sheared off of the crank causing the spark to come late, but I don't really know enough to say if that's what is causing it.

I know the starters self-destructing is a common problem on these bikes so I'm hoping someone has had a similar problem.

A sheared woodruff key is a common problem and could be your issue.

I've personally had the sheared woodruff key problem on the flywheel, and my symptoms were similarish to yours. I'd recommend checking for it.
As for the starter self destructing, I've had that problem too. Make sure you red loctite the nut on the end of the worm gear and check all the bearings in the starter system to make sure crap hasn't seized them up.

Thanks for the responses. Today I pulled my flywheel off and sure enough the woodruff key was sheared in half. I've had the starter system completely removed since january and I'm just not going to mess with it anymore since I'm perfectly fine with kickstarting it.

Is the woodruff key a proprietary part or is it just something I could find in any hardware store?

Just take both bits to a bearing shop. It’s a standard size.
Use some valve grinding paste to lap the flywheel to the crankshaft then give it a good clean. Then use some loctite 638 retaining compound and refit the key and flywheel.

I ordered a new woodruff for like $3, shipping kind of sucked though so I combined it with other stuff.
https://www.ktmpartspro.com/oemparts/p/husqvarna/151371301/woodruff-key

Today I picked up a 3mmx5mm woodruff key and that solved the problem. It runs great now, thanks for the help!