Hello All
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I purchased my Ninja EX250 about 2 weeks ago, all seemed find until lately when I am in 3rd or 4th gear I notice a slight sputter around 6 to 7500 rpm once gas her through shes golden just when Im in half open throttle she seems to want to do it. Any ideas guys? Thanks! I hope its not nothing major it is my first bike and am really excited about it just hope its nothing major. However, other than that she runs great idles around 1500 to 2k barely sputters at idle.

Assuming everything's stock (no re-jetting, exhaust, etc), this is probably just an adjust the valves and re-sync the carbs problem. When I got my bike, it had a sputter around 8K but ran great everywhere else (except a high idle, but that was a different issue). Adjusted the valves (they were too tight, every single one), synced the carbs, and it ran like a champ.

http://faq.ninja250.org/wiki/How_do_I_adjust_the_valves%3F

Good luck, keep the rubber down.

-Kyle

Mine tends to do that too in the midrange between 6-7.5k or so. I had it checked at the 5500 mile service and they said it was fine. Even after the service it still did it. Taking it to a different shop for the 7500 mile service as soon as I can afford (moving expenses stopped me from doing it this month :( ). Hopefully this shop will adjust things the right way and not rip me off. They already did good once in helping me find an electrical problem and drill out two stripped fairing screws for a decent cost.

Whoever between the two of us gets the valves and carbs done first should come back here and say if it fixed the sputtering or not. I will say though that it's nothing serious. Just a fuel/air mixture out of alignment type of thing and for me goes away if I either go through mid-range quick or as soon as I get it past 8k.

Will do definately, will probably be another week or so. I still enjoy it though.

Clean the pilot jets. The fuel these days clogs them enough to do this if just sitting for a few days.

Clean the pilot jets. The fuel these days clogs them enough to do this if just sitting for a few days.

Definitely +1 on that. I left the bike sitting for about a week, and then I had to drain the bowls to get the bike started again. What's up with the fuel nowadays?