bike has horrible misfire below 4000rpms then clears up

[firefightergib]

alright here is the story i have a 05 busa, i bought it from a buddy of mine it had 4000 miles on it, the bike ran great but the FI light was on, so i scan the light and it came back to a C22 code. I ordered the ambient air sensor, along with a 4-1 exhaust, while I had the bike apart I just figured I would do it all at one time, so i changed the sensor, put the 4-1 exhuast and done the airbox mod, now the bike has a horrible misfire below 4000rpms, but once it gets to about 4000rpms it just takes off and runs good. It has no FI light and no codes now, im thinking that it maybe the map cause I put the exhaust and airbox mod, im thinking I need to get a power commander and remap it and that will fix the problem but i want some more input before i do that. Thanks

[jwcfbd]

I believe you are correct about needing a power commander. I know most guys here say you need one if you just do a full exhaust system but you also did the airbox mod. So I'm pretty sure that will fix your problem. Give the board some time and someone that knows for sure will post up the info you are looking for.

[Mr Brown]

Check your plugs. They are probably fouled.

[kml]

Reattach the air pressure sensor hose on the bottom of the air box. Sounds like it it was not properly reattached after the air box mod was done. If it's not attached it will cause the exact symptoms you describe.

cheers
ken

[schleife]

While using a 4in1 exhaust the Secondary-Air-System needs to be shut off. Otherwise you'll get the misfires when throttle is closed.

On the right side of the airbox you can find the hose going down to the "spider" in front of the engine. For testing purposes:
1) Pull down the hose from the airbox
2) Put a srew (with a head bigger than the hose's diameter, e.g. the chain protecter's srew) in the hose and put the hose back again
When done, try and check if the misfires are gone.
If not, remove the srew again....

All in all it's a 5 minutes test.

Ciao
D1

[firefightergib]

found out the problem, the fuel line was kinked, i got it unkinked and everything worked fine, went to the track today and ended up running a 9.88 @ 143mph w/ 1.755 60ft

[firefightergib]

well thought that was the problem, the bike ran fine yesterday when i took it to the track, but i got out there and road it today and it had a horrible misfire all the way through, the only way it doesnt misfire is if the throttle is wide open.

[kml]

Is #3 hose connected?

[firefightergib]

changed spark plugs today and seemed to cure the problem, maybe, hopefully lol

[freakshow23]

Did the plugs cure your problem? I'm having the same issue with mine and it's drivin me crazy.......