110cc A couple of loud squeals and now won't start
 

ATV has about 7 hours on it. It was running fine and starting fine. After being driven at high speed, it was just slowly coming to the garage and made 2 high pitched squeals (sounded like the starter had engaged). After the noise, the starter still engages but it isn't turning the motor over. I have taken the starter off and it operates properly, no broken teeth. I removed the cover with stator etc. enclosed and the chain is not broken and can easily be turned with 2 fingers which I believe is not good. I haven't disassembled any further. Any idea what is broken or loose?

Yikes.

No offence intended when I ask: is it out of oil? If so, I wouldn't even bother tearing it apart. Replacement engines are readily available at decent prices.

It has oil in it, the issue is that the larger sprocket that the starter engages spins freely and doesn't turn the motor over. Just wondering if anyone knows if this is just a shear pin, key or how exactly this is supposed to engage with the engine. I'm going to get a puller to get the flywheel off to see behind it, just want to know what I am looking for and if I can even access it without opening the motor up. Thanks.

So, your starter engages the crank with a gear? I've got a 50cc here that I haven't dismantled, but it appears to connect the starter to the crank with a chain.

Yes, the small gear on the starter is connected to about a 4-5" sprocket by a chain. It is this larger sprocket that I am wondering about... how it connects to turn the motor over.

Upon re-reading your first post, I see that I misunderstood. It sounds like your starter does engage the crank with a chain. Sorry, I haven't pulled one apart far enough to know if the sprocket is retained with a key or fasteners.

When you get a flywheel puller, please take some pics and document the process.