So i just got my bike together (98F3)and i am still having issues with getting it to run well.... It will ride out fine in first gear but starts to jerk hard in 2nd and wont move at all in 3rd 4th 5th... like its running out of gas is what i think... i can feel thefuel pump thumping while i ride... and i replaced the fuel filter. choke is not sticking... i am not running a air control valve i just have the tubes exposed under the tank... has anyone else run without the air solenoid? If so how did you plumb the lines... the only line i have hooked up is the fuel line and the valve cover to airbox line... there are at least two other hoses....should i even worry about them? Someone was supposed to sync my carbs this weekend but i dont think that will get me anywere the bike will sit in neutral and rev all day long.... it does not sound like the carbs are out of wack it is a very sharp rev...however there is occasional hessitation when i rev the bike..... maby my rev limiter is malfunctioning (can i cut a wire or something to eliminate that) ( can i test the computer without replaceing it)... maby the carb bowls fill and then i run them dry and the bike dies???or starts to run like sh*? several times the bike has run all through second fine shift to third....nothing..... wideopen throttle it quits.... then i have to crank it over several times to get it to fire again.... i am lost... i will disconect the fuel line post pump and see if its shooting out but i thought you could gravity feed this bike anyway...this is a stunt bike so no gauges... thought that could be it (computer run through guages?)
i am getting a sh*? load of spark when just turning the bike over in neutral...I also know there are no stuck valves etc... i just had the motor apart and it turned over beutiful by hand and i visually inspected all the valves.... OH and the other thing is it is backfiring or light pops when engine brakeing....the book says that could be a lean mix... i dont know what to do about that so whatever... I hate to just start buying parts... i have some spare carbs i will try to clean and put in... does anyone have any tests i can try? any ideas? Sorry for the longwinded message im just not getting this thing at all... Thank you Ryan

 

Just brainstorming here but i havea gsxr and it has a fuel tank to airbox breather hose that has to be connected for proper air pressure in the tank..... two questions.... on the CBR i do have to pipe nipples comming out of the rear of the tank i assume one is a breather and one is a drain... is the big one the breather? what does it get hooked up to? could this be my issue? my fuel tank does not lock(no pressure in the tank just atmosphere...could this be an issue? i guess thats more than 2 questions.... thanks guys. Ryan

 

My bike did the same thing when I tried running with the air system incorrect.
It would rev nicely in neutral, but the minute I tried taking it on the road it would sputter and misfire.
If I remember correctly, it went well up to 4-5000 rpm, then it started misfiring.

 

Hey man have you looked at the air filter lately? Check to see if it is clogged, or dirty. I think that might be the problem. If your engine can not breathe it will not run. At a low idle in nuetral it is not requiring much air, as you begin to increase your speed the engine needs more air, and when you open her up (WOT) if your filter is clogged it will stall. Also the backfiringis caused by an improper fuel mixture, which in you situation is a whole lot of fuel, and not enough oxygen, when the raw unburned fuel is sucked out the exhaust valves and when it touches the hot exhaust it ignites and you get a backfire.

 

I actually ran the bike with no airfilter because my K&N looked dirty but you can never tell.... I am really hoping to figure out all the vacume hoses.... and secondary air intake because i dont have any of them hooked up at all... I would like to find a pic of someones that have bypassed their air solenoid.... thanks for the ideas though guys
Gunner... what do you mean air system incorrect? thanks

 

Frankinbarnes, I had the filter out and some hoses were not where they were supposed to be.
But it's been a while, and at the time I guess I also had old plugs and an engine that hadn't ran for a year.
It revved like a champ as long as it was in neutral, so I never thought it was the air filter.
But when I got the stock filter in there it was a new bike. (I may have replaced other parts at the time as well, but like I said it's been a while)

 

thank you gunnar im gonna work on it this weekend and ill let you know how it goes.

 

hey bro, ever get that thing figured out? mine is doing the same thing... think it might be the air hoses that go to the carbs... im going to run the 2 smaller dia. hoses in into one hose and then up to the ram air box, then the larger center hose to the other port on the ram air box and see what she does.

let me know if you got yours fixed and if so, what was wrong with it.