Hi Guys. I recently acquired a 1996 CBR600 F3 and I've noticed that in certain gears, at certain RPMs, the bike just loses a lot of power unless I'm accelerating.

When I'm in 1st gear, no problem
2nd gear, no problem.
3rd gear, like when I'm on a major street, as I start getting into 6000-8000 RPMs, like when I'm cruising, the bike starts to sputter tremendously.

Same thing for the other higher gears. If I'm on the highway and I get the bike into 4th or 5th, it just sputters a LOT in that same RPM range. The last time I rode it, I had to keep it up around 10,000 at 75MPH on the open highway just to maintain speed. If I upshifted, the bike just seems to lose a TON of power in the 7000 RPM range.

What do you guys think it is? Carb need cleaning out?

 

Could be dirty carbs or incorrect jetting. Start by pulling the spark plugs and evaluate how its running. I'd replace them anyway, they may be the problem. Inspect or replace your wires as well.

 

I'm having the same issue in 1st and 4th gears, it sputters and tries to cut out at 4500-5000rpm, only on acceleration though. And while I'm cruising the lights are dim, when it cuts out the lights go nearly dark. Regulator/Rectifier?