Well its been a while since Ive got hung up on a F3 but this is sort of an oddball problem, whenever I try to start it all I get is backfiring...I have brand new NGK R sparks, and Cleaned carbs from honda, air filter is new, and I know its getting fuel because I took the sparks out and they were soaked in gas...so what i am thinking is its a timing problem?? any thoughts or suggestions? im goin to take the statorcover off tomorrow when i get back to work and check out the flywheel...if it is a timing problem how do i fix it?

 

iv not had this problem but i know that it is caused by over fuelling and cant see how timing would effect it. are you sure the carbs are setup correctly? have you tried bump startin it ? are the spark plugs the original type? are the spark plugs the correct distance? not sure if any of this helps but worth a think about

 

are you sure its getting spark? are you sure the plug wires are hooked up in the correct order to the spark plugs?????

 

^^^^ Ditto, that was my 1st idea. If your bike was running ok before, then it's odds on that its something you have done. (although Murphy's Law: "Anything that can go wrong, will go wrong & at the most inconvenient time").
Back track on what you have done. The only other thing that comes to mind is that your reg sh*t itself in the mean time.