i have an f3, and when i crack the throttle on it, it dies out, if i roll on the throttle, its runs fine. why doesnt it want to go when i crack the throttle? carbs out of sync? dirty carbs? other problem, idk,... im totally lost, it has a new fuel filter, new air filter, i put the f4i gauges on it, i cleaned the carbs on it about 2 weeks ago

 

Could be out of sync. Throttle hesitation into normal engine speed tends to be lean. Bogging or dying tends to be rich. How did it run prior to your tinkering?

 

well it didnt run when i got it, sat in a barn for about 6 months, i cleaned the carbs and got it to run, rode it around a little bit and it ran ok. i tried to sync the carbs today, get all the mercury lines level with eachother, got them there, and then the bike started to do this, when i first put the gauges on the bike to check the sync it looked like the carb 1 had a crazy amount of vacuum while all the others had barely any

 

Well you synced so that is out of the way. Check your spark plugs, they will tell you if you are running rich or lean. Also, it never hurts to do a compression test if you have the gauge handy. Id do one on a bike that didn't run when you bought it.

 

playing with the throttle some more, it seems to want to hang around 3000 rpm and slowly come back down, really slowly. i think something went wrong when i synced the carbs, idk what i did, but it seems to be showing sings of out of sync carbs, the bike has good compression checked that a little while back, i have only had it about 2 months, so it was pretty recent.

 

how do plugs look? hard to screw up syncing unless you built a home tool and botched it. If the gauge is good, and you hooked it up properly, and the lines were even, you should be good to go.

 

how does the choke affect it? If it runs better with the choke on its a lean problem.

 

i just encounter similar problem on a 10min. ride.
switched to reserve and got straight to the gas station, put 2 gal. in and switched to on.
it was fine after that.

have you checked your fuel level????

 

yeah, I kinda skip the simple things sometimes... lol. Are you getting fuel and is it fresh?

 

with it sitting like that i would look inside that tank to see if any build up has occured. alot of times people will just rebuild the carbs on a bike that has been sitting but they wont clean out the gas tank.