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Misfire below 4krpm (k4 gsxr600)

748 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.
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So any idea why at take off it bug out (misfire) almost imposible to take off and now even more questions why it have 60 psi on all 4 cylinder but ones it pass 4k rpm it have lot of power like new?
The 60psi is most likely you have the wrong type of compression tester. Not suitable for bikes.

The video sounds like a misfire, could be coils or injectors related. I'm leaning towards coils,
because you said it misfires under load and when hot. You said that you replaced all the coils. Were they new items?

Edit: ( I see you started another thread, so I will go there).
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