So I tried starting my F3 today. I drained all the gas out of the tank and put fresh premium in it. It started at first and wasn't running right. It only got up to about 500 rpm idled for about 5 seconds and died. Now it won't start at all. Here's what was done to it last year. Replaced the fuel pump, had the carbs cleaned, and got new plugs. When I went to put it up for the winter I put some sea foam in the gas. I also replaced the air filter over the winter and it started after that. Is it possible that the sea foam fouled the plugs and dirtied the carbs? I'm getting a strong gas smell like it's flooding and then it back fires. HELP 50 degrees ina couple days and want to ride! HELP ME!!!!!!!!!!!!!

 

when was it run last? Seafoam has never caused any issues in my vehicles, although I thought it was designed as a fuel additive to be run though a normal tank, not a fuel stabilizer.

I'm assuming you're using your choke for cold cranking.

check your air filter and airbox. Make sure a mouse or something hasn't found a winter home. (If the bike's been sitting a while without being run, that should be done before cranking.)

Pull your plugs, check em, check spark on each one, and then reinstall once you clean em up and the cylinders have had a little time to breathe.

Check your pipe - make sure there isn't anything in it blocking exhaust flow.

 

it was started and ran fine about 3 weeks ago. let it warm up and reved it to wake up the neighbors (i dislike them). and nothing in the pipe.

 

anybody else have any ideas?

 

It sounds like its fouled. Buy a new set of plugs. While the plugs are out, crank the engine over a few times to clear out any gas that may still be in the combustion chamber so you don't foul your new plugs.

Put the new set in and you'll be ready to go.

Also, be cautious when its below 40 deg's and you start the bike. early cbrs are well known for not liking cold weather and fouling plugs, especially bikes that have sat for period of time. If the bike has sat for more than a week in the cold, the battery should be fully charged with a charger to prevent the plugs from fouling due to the engine not cranking over fast enough. It doesn't take much at all to foul the plugs, and once they do, you should just replace them.

It certainly doesn't sound like anything other than just the plugs being fouled. smell of gas and backfiring... I'm assuming by backfire, you mean the woosh through the exhaust, not actually through the carb correct? If its through the exhaust, its just the build up of gas in the exhaust, then a plug may fire, and ignite all of the gas in the exhaust. thats where it comes from.