My GZ sputters when I accelerate? why?

[edtron]

How is it going guys. I bought a 2010 GZ250 last week, it only has 150 miles on it (almost brand new)...
The previous owner had the bike sitting at garage for about a year or so... Now when I ride the bike and accelerate hard, the engine sputters like if it had no gas. It only sputters when the throttle is nearly or fully opened. Why is this happening? and what can I do? FYI: I always warm it up for 2 minutes or so before riding. please help me out, thanks. -ED

[mrlmd1]

Clean the carb - try first with Berryman's B12 Chemtool or Seafoam to soak in the carb for overnight and if that doesn't work you may have to remove it and thoroughly clean out the jets. It's likely gummed up from sitting for a year not being used. Also change the gas and put in fresh stuff.
And you're not riding it like that with the choke on, are you?
You also have to go over the whole bike, check tire pressures, fully charge up the battery if it's still good, check the oil, check that all the lights and safety switches work, make sure there's no critters living inside the exhaust partially obstructing it.

[edtron]

Thanks I will try all those things, and no I dont run it with choke on...hopefully I'll get it running ok

[Rookie Rider]

Check your idle knob too, welcome to the forum.

[Road_Clam]

Originally Posted by edtron

How is it going guys. I bought a 2010 GZ250 last week, it only has 150 miles on it (almost brand new)...
The previous owner had the bike sitting at garage for about a year or so... Now when I ride the bike and accelerate hard, the engine sputters like if it had no gas. It only sputters when the throttle is nearly or fully opened. Why is this happening? and what can I do? FYI: I always warm it up for 2 minutes or so before riding. please help me out, thanks. -ED

I about guarantee you have some residual E10 "skank spooge" inside your carb that is partially clogging your jets. E10 is BAD if left untreated in your fuel system. I agree with others as you will need to dissasembly your carb for a cleaning. In the future make it a disciplin to add some type of Ethanol fuel treatment. (I swear by Startron) also Stabil Ethanol formula is great too .

[edtron]

Thanks guys I will try to do that, ill post back to let you guys know if that worked

[b1pig]

i'll jump on this bad-wagon....

i have removed and cleaned the carb on the wife's GZ twice. it idles wonderfully, but above about 1/3 throttle, ours also sputters, flattens out and seems to be running lean. however, if you run it on up through all the gears... it will pull along to the 60's. if you creep through the gears, it will not produce enough power to roll past 45.

gonna pick up some seafoam tomorrow and give it a soak. hopefully that will resolve the problem on ours.

[jonathan180iq]

Originally Posted by b1pig

i'll jump on this bad-wagon....

i have removed and cleaned the carb on the wife's GZ twice. it idles wonderfully, but above about 1/3 throttle, ours also sputters, flattens out and seems to be running lean. however, if you run it on up through all the gears... it will pull along to the 60's. if you creep through the gears, it will not produce enough power to roll past 45.

gonna pick up some seafoam tomorrow and give it a soak. hopefully that will resolve the problem on ours.

Your mid range is affected by the needle jet. Since it sounds like your bike works fine at low speed (pilot jet) and at 3/4-full throttle (main jet) then you can probably get away with simply pulling the top diaphragm cover and cleaning the need passages.