I have a 99 CBRF4. It's always ran good except for once the plugs went bad, no biggie. The battery has been dead all winter, I replaced it the other day and the bike fired up and ran good. I have started it several times trying to run out the old gas. It ran good everytime. Yesterday I started it up and it ran for about a minute, I walked off just letting it run and it died. I went back to start it and up it wouldn't start. I thought maybe it had flooded. Tried again last night and nothing. Got up today and pulled the plugs, looked ok. Cleaned them and reinstalled. Still nothing. Thought it was possibly the fuel filter so pulled it off and it wasn't bad either. Anyone have any suggestions?!? I'm lost now and this really sucks! Thanks in advance!!

 

You let it sit all winter and you said it had old gas. If it ran fine before I'd go with the assumption your carbs are all gummed up and the idle jets are clogged. If your mechically inclined and have a manual you should have no issue cleaning them yourself. I just installed a jet kit in mine, its not all that difficult, though can be a bit time consuming.

 

I was thinking it may have been caused by letting it run out the old gas, and it still may. It ran good until it died then nothing!! Cleaned all the plugs and checked them to make sure they fired which they did. I then drained all the old gas and put in new, nothing. Cranks great, getting fire, no start. I pulled the fuel filter and it felt like the line going into the fuel pump was getting vacuum when I tried to crank it so I assume it's working. I might take it back down and try to clean out the carbs. thanks!!

 

Im leaning away from bad gas and towards the charging system. Depending on your idle speed, the alt cant keep up with power consumption, hence the bike dying while idling. charge er up and give it another shot

 

Def the idle jets i think. Head over to the how-to section there is a nice writeup done. I added something on the bottom of the first page on how to clean the idle jets

 

Awesome Red, thanks. It's not a charging issue, it will crank for a LOOOONG time. It cranked great after it died, just wouldn't start.

 

I have a similar problem with my bike. I stored it over the winter and didn't put a charger on the bat (bad idea) and after the old gas (with fuel stabilizer added before winter) was run out, it started to run a bit choppier and idle a lot worse. I'm also smelling a way stronger scent of gasoline when idling. Think that's due to the idle jets? It's not to the point where the bike is dying, but at idle the RPMs definitely drop a lot and it stumbles when opening up the throttle.

 

My bike was really bad when i would try and rev it from idle. I had the carbs synched (sp?) in mid april and its a TON better now.

As for sitting all winter, the only way to keep the carbs from getting all nasty from sitting is to have them be dry (drain the gas). I'd say unless you run it once in a while during the winter, clean em out before you go for the first ride. It's just cheap insurance that it'll run good while your out and about.

Personally, I started mine up about once a month or so, or whenever it wasn't cold as heck. I'd let it run for about 20 mins, just to keep some gas flowing and keep things clean. It also helped with the battery too. I'm on the same battery that came with the bike almost 2 years ago.