Why does my bike do this?

in the morning i start her up and shes got a new battery!! which helps a lot. so i pull the choke all the way out (its a gn250 and its 2007) then as soon as it starts i put it half way in then i watch the revs go up and when they start to come down (within seconds) i turn the choke off and let it warm for a coupla seconds. But when i take off up the road (a minor hill) it makes this kind of gulping sound. almost a nearly stall. but not. I imagine a petrol sucking kind of sound.


What is this do you think? Is it just getting used to going again after resting all night?
Why does my bike do this?
Your bike is NOT completely warmed up if you are only giving it few seconds.





Try leaving the choke on (half way) for few minutes. In fact try leaving it on for few minutes (especially climbing a small hill with cold engine).


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On my 700cc motorcycle, the choke lever was actually at the handle bar so we can adjust it while driving off.





Good Luck...
Why does my bike do this?
let your bike warm up on the choke for a bit longer,then put coke off and see if it revs smoothly if so it should be ok if its not warmed up enough it may cough and splutter
Reply:The tank on your bike is switched to the on position I assume? I'd guess that you have a vacuum operated fuel feed 'switch' or valve (a relatively recent change) keep the choke on a bit longer and see if that helps. To get up that hill you are trying to rev up the motor and losing vacuum, so your fuel feed is probably shutting down (designed to only allow fuel flow while the engine is running so when your vacuum drops, your fuel flow follows).





Does that sound like what you hear? Because mine doesn't have a 'high tech' switch like that. I'd guess it is made worse by being a small motorcycle, too.


A situation like the old vacuum operated wiper mechanisms! It would be dark out, and you'd want to get home before the storm hit, so you switch on the wipers and as you accelerated your vacuum dropped and the wipers would slow down. Amazing!
Reply:Let it warm up a bit first and gear down on the hill.
Reply:It will happen so by two reasons. Either it is not heated up properly. So keep the choke on for about 5 minutes.


The second chance is over flow of the petrol to the carburettor. When you had a strting trouble at first, you would have accelerated it too much. So kick and kick, until the overflown petrol has been burned up.
Reply:sounds like you need to let it warm up longer. most newer bikes are jetted lean from to factory for emissions standards. the leaner the jetting the longer they take to warm up with the choke, which is richening the mixture.
Reply:1. the bike is not completely warm


2. you're gear is too high....downshift


3. running out of gas
Reply:You're not warming it up enough. It's correct to disengage the choke after the RPMs spike. The spike doesn't indicate that it's ready to go. It just means it's running on thin or no air and straight gas.





Give it 2 or 3 more minutes and you should see your issues disappear.