hi guys, so this is may problem, i have a flat spot between 4k and 6k
its a 97 cbr 600, the bike has been siting for 1 year before i bought it.
so i think the carbs need some cleaning. but its possible that it could be the air control valve, because after 6k it pulls well and strong.
and down low its ok, only the idle is a bit jerky.

so what could it be?

thanks

 

When I bought my 98F3, it came with a D&D muffler/after-market 4>1 headers and
stock jetting. I had a dead spot in the 4-5k band as well.

When I went back to the stock 4>2>1 headers and exhaust, The dead spot went away. So you might have a similar issue, if the exhaust isn't stock.

Ern

 

It's lean in the mid range. This is affected by the needle being activated. If you have a jet kit go down one notch, towards the bottom. If you don't you can try and shim your stock needs with a few small washers.
Carb tuning is half science a quarter luck and a quarter magic so good luck.

 

maybe... just maybe it's this https://cbrforum.com/forum/cbr-600f3...5k-rpm-101283/

 

thanks guys
the only thing the bike has is a slip on, everything else is stock,
at this rpm it made me think it could be the air control vaulve, because it pulls well then stops and goes again.

 

hey guys update on the flat spot, os i bypassed the air control vaulve and nothing, so i now im taking of the carbs to clean, and when i took of the air box there were 2 gaskets missing but it cant be just that, so im taking them apart to clean. when i give it a dab of throttle it goes fine to red line but more then half or full throttle it bogs around 5k and starts going again around 6,5 k

 

so here are some updates, opened the carbs found some crap in there and clean it up, my main jets were 138-140-140-138 being a 97 f3 is this stock jeting. all i have is a slip on and everthing is stock.

and i tryed to take the needles out but i couldnt, is there any trick?

so what do you guys think?

 

anyone?

 

Hi Jordan. Yes, the jetting you described is stock. Adjusting carbs is more involved than you're being told, but cleaning them is the right thing to do.

Here's what you're looking for: https://cbrforum.com/forum/f2-tech-9...g-101-a-96888/

 

thanks ReconnaisanceMan

update, so i cleaned up the carbs the best i could put everthing back together and.... continued the same, give it a bit more gas and it bogs until it gets to 7k rpm, dosent matter the gear. and even at 7k plus rpm it somtimes missfires. not to talk about the idle thats dosent stop moving until it dies, it bounces between 1 and 1,5k rpm

everthing in the carbs is ok, just dont have the sub air filter fitted in its running directly from the ram air, taking care of that.

so i tought it may be valves, but i took of the left plug and it was like this








i just took the bike out for 4 rides since i bought it and changed the oil, oil filter and air filter, the air filter that i changed was almosed cloged, making the the bike rich.

so as everthing else is stock, the only thing i have is a viper slip on, but i dont think its the problem, could it be the pulgs, do i have to buy new ones or is it possible to just brush this ones off? did this happen to anybody?

thanks in advance