Starter gets stuck sometimes, engine wont turn over

[2005600katana]

It started doing this a few months ago, and its got a pretty new battery. When I let the bike sit for a few days and go to start it, sometimes the starter will get stuck (it will just click) and I have to keep tapping the starter to get it to start again. So far I can always get it to start but it takes a minute. One time (only once) it backfired pretty loud while doing this, like the engine kicked back or something. If I have already rode the bike that day, it wont do any of that and starts fine.
Just wanted your opinions on this. I guess it could be the starter, but it kinda seems like the engine gets stuck on the comp. stroke or something. The starter when working spins fast and sounds fine.

Edit - Its a 2005 600 Katana. Thanks.

[Rod]

you could need a valve adj. or carbon buidlup, ignition or cam timing how many miles do you have and what was and when the was serviced done.

[2005600katana]

Its only got 1900 miles and was serviced by Suzuki at 1200 miles. Once it cranks and warms up a little it runs fine. It always skips/runs rough for a few minutes when its cold out but clears up. It might need new plugs.
PS- Im in South Ga so it doesnt get extrememly cold.

[Rod]

Thats realy low miles this should not happen ,How long ago was the service work and what did they do.

[2005600katana]

It was about a year and half, 2 years ago but it hasnt been rode much. I always atleast start it when its been sitting more than 2 weeks.
It was serviced when I bought it. They changed the fluids, plugs, and ckecked the timing and everything else I believe. It just started doing this out of the blue this winter and like I said it only does it after its been sitting for atleast a few days.

[Rod]

If you have a service manual and a meter you should do the test in the manual for the starter system to rule out electrical.but that is a little bit advanced. but if it only happens on first start up of the day probly not electrical.

[2005600katana]

Well now it wont idle and runs rough/backfires a little under 3K RPM. Above 3K is fine. Seems to want to idle okay until its warmed up and then it will die if you let off the throttle. I havent ridden it in about a month or more, and the gas is 2-3months old. Should I drain the tank and refill with Chevron techron cleaner and see whta that does? It has been sitting alot.

[2005600katana]

Lol I just took out the air filter to check it and the airbox is 1/4 of the way full of gas!!!
I did leave it on PRI while it sat, stupid I know. You live ya learn but could this airbox full of gas be causing some of these problems?? Im going to clean it up now.

[Rod]

nice good luck