On my 73’  at3 i had to replace the gear behind the clutch basket because it cracked i did that put everything back together following the manual new seals i even remembered the shim for the kickstarter i put the clutch cover on and i kick it and it works but with any amount of force past whats needed to barely turn it over the kickstarter sticks and stays meshed with the idler gear i have spent far to much time trying to fix this to no avail trying so many things i dont know what to do any ideas?

First thought is the tension clip missed its guiding slot. i'll find a pic. Ok found a video for an RX135 but relevant in showing where the clip fits in the slot. Go to 5 minutes should be close.

Second thought is maybe the idler gear picked up a burr when the gear behind the clutch basket broke?

I didn't have the audio going.

Be unusual to knock a tooth of that gear. Did it do something like run backwards. I'm thinking magneto like my AT1 but i guess yours is electric so unlikely to happen but possible. & yes--as Mark says above.

Yes it was running backwards

I have tried multiple idler gears i have a spare motor with a rusted out crank

I bought a brand new clip and tried that but it keeps jumping out

The drag on the clip is what makes the gear work right. 

Maybe you can take a video and post it on YouTube or someplace and link it here?

Ok, if it was running backwards i'd be worried about the three gears plus the stop on the shaft but that probably survived. So 'i think' get all three gear--or make that two gears as one is replaced. Roll the idler & the kick gear together. Kick gear off the shaft for this. & hopefully will show up a bent tooth.
Kick gear only operates for half a turn so always the same teeth for that half turn. So if you find the lumpy tooth you might be able to put the kick gear back on the shaft around half the number of splines--twisted splines. Bit dodgy doing that & i've not needed to. Ideally 3 new gears including the one you've done. Hope you manage to sort what caused it but no need to tell you that.