I have a 1998 CBR900rr.I just changed the plugs,put a K&N air cleaner,inline fuel filter, jet kit(127.5 jets in #1 and 4,130 jets in # 2 and 3).The stock jets were #120.Synchronized the carbs.Yoshimura RS-3 muffler.The bike sounds awesome.It has a nice idle,lots of power.But when I got to beginning of red line (10,000) rpm) and was about to shift I noticed a hesitation.Almost like it had a fuel loss for a brief second.

 

sounds like yer spot on whit the mods, just to be sure , did you drill the small hole in each of the carb slides during your jet kit install? also did you adjust everthing to carb#3 during your sync process?

 

The drill bit that came with the kit for that mod was smaller than what I already had.Maybe a previous owner did it already.I had synchronized 3 & 4 together,then 1 &2 together then the pair together.

 

might of had a large jet kit in it at one time, is your jet kit a "dyno" brand? if so , call tech support and ask about hole sizing and see what they have to say. Also i would ride the thing a bit more and see if that was just a glitch , could be that something small has worked itself out...

 

Is your charging system up to snuff?

 

Battery is a month old ( reads 12.65 volts).Rectifier is a year old and I did a charging test.Revved up to 5000 rpm battery reads 14.2 volts

 

If your jetting was off, it'd show up before you hit 10K. Have you stayed in the throttle til it hit rev limiter? Just curious if maybe your tach is off. On a sidenote, never been a fan of or bought into the idea of having 2 different size mains. I've always used same size jets and plug readings are consistent on all 4. Do you have fairly low humidity in your area? I'm in middle Tenn. and humidity is usually on high side. 122-125 is usually good range for here with aftermarket filter and full system.