backfire and broken keyway

[stang7tl]

so my 2001 500 HO backfire sometimes seem only when the float stick and I shut it of then fire it up again it has broken the keyway and help?

[Russ C]

if float stuck , checj=k crancase for gas in oil

[stang7tl]

this is current top dead center and where the flywheel is set and how far pass the pulse sensor the striker is

[stang7tl]

so as you can tell at TDC the signal to spark has already happened. I was thinking it needed to be at TDC as the signal get sent. just ready some info online says it does need to be a bit before TDC. Please if anyone can help.
If I put a new keyway in it starts right up will idle and will rev up seemed fine. then it random broke another key so my question is can the float randomly getting stuck make it backfire? Lastly a local bike shop said the keyways are made to break if the bike backfires to prevent other damage does that sound right? I thought the Keyway I got was just junk

[kcaves]

it does need to fire before TDC, and I've never heard of the keyway breaking off because of a backfire, sounds like a load of crap to me, only machine I've ever seen do that on a regular basis is the predators

[stang7tl]

really would like to get this figured out the I bought the bike for myself for christmas(Thanks to a refund of a costa trip for the girl and I since she failed out of the relationship lol) I have put a lot of new parts and fun toys on it but yet to really ride it

here she is day one in the truck
all my hard work

28" mud bugs ready when I go test run it