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Misfire below 4krpm (k4 gsxr600)

750 Views 11 Replies 3 Participants Last post by  peter079
I ride my bike for like 45 min and it was perfect but i came to a stop and when i try to take off bike start hesitant bad (like misfire) to the point i stall 3x. The only way i could take of was having rpm over 4k and it jump bad like misfire until clear after 4k rpm was stable. So long story short below 4k rpm sound like misfire and hesitate hard, one i pass 4k rpm is like the bike is new.

I ready replace the following parts:

Spark plugs (2 different sets)
Ignition coil
Fuel pump
Fuel filter
Replace vacuum lines on buddy throttle

Any idea or suggestion.
1 - 4 of 12 Posts
Take a video and load to youtube.
Might be time for a compression test. Did you just get this bike? You might want to just check the cam timing as well. If someone else got in there and tried to adjust and made a mistake, it can cause weird issues.

The other thing to try is unplugging sensors one at a time to let the ECM insert the static values. It could just be the ECM doing the right thing with bad data.
At 4k rpm, the air doesn't have time to leak out before ignition.
I would have to put hands on it and perform some diagnostics. Also at low RPM, the engine has a higher vacuum. Could indicate a problem with the IAP hoses/sensor. You have to do the diagnostics.
1 - 4 of 12 Posts
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