My bike backfires on startup what causes this and how can I fix it? the bike is a 04 fuel in jected Deuce. thanks

 

Could be a number of things.
Plugs, the way U start it or even how U shut her down, even the tune.

I've read in here sometimes those that use the kill switch have a backfire on starts.

Also those who rev is a few time before shutting her down get it.

Plugs may need replaced.

Tune may not be on the spot. Seems like those with The PC - F/M have it often. If so might need to tweet it.

Also might read through some of these to see if it helpsl

http://www.google.com/search?source=...w=1271&bih=628

 

I have had a backfire on startup just 2 times on my FI Heritage. Seems I narrowed it down to 2 things. Shutting it down quickly and not letting it settle at idle for a second first, especially when hot, and hitting the start button and expecting it to fire right away like it usually does, only to have it crank over a time or two, but I already had let off the starter button. That will get it to backfire every time. I think it pumped enough fuel to start, just didn't fire, so next fire up right away had extra shot of fuel. Again, only when it is hot.