Not exactly sure how to explain this but here goes. I have a FZX250 Zeal that seems to run fine with no real issues except one. If I rev the bike to quickly she stalls, if I slow it down a little she'll splutter then rev up normally and when I gently (not to gently) rev it all is fine. I've had the problem from day one and initially thought it could be stale fuel as the owner told me it hadn't been ridden much and the fuel was probably a month or two old. I also notice that when I practice my slow speed maneuvering I'll give her a little throttle with little response so I'll give it a little more and the bike would lunge forward. I'm still learning so figured all I needed was practice but now I'm thinking perhaps there's more to it. I use unleaded fuel, not sure what else I can say. Any advise would be great, thanks. Forgot to mention when warn it's a little better but she'll still stall if I rev it to quick. Just re-read my post and it's a little confusing, when I say rev the bike gently and all is well I mean if I slowly roll the throttle on to full throttle she behaves and wont stall.