Why does my bike misfire at higher revs?
A misfire at higher RPM is one of the clearest signs that your carburettors aren’t fuelling correctly. When you open the throttle wide, the engine relies on the main jets to deliver the correct amount of fuel. If those jets are dirty, partially blocked, or incorrectly sized, the engine will stumble, hesitate, or misfire.
Another common culprit is float height. If the floats are set too low, the fuel level in the bowls drops under load, starving the engine of fuel at higher revs. On performance bikes like Yamaha R1s, Honda Fireblades, or Kawasaki ZXRs, even a small deviation from spec can cause serious high-RPM misfires.
Worn needle jets or slides can also play a role. As the components wear, fuelling becomes inconsistent, leading to flat spots and erratic power delivery. Electrical issues like weak coils are sometimes blamed, but in most cases, the root cause is still within the carbs.
At The Carb Shack, we completely strip and ultrasonically clean every carb, replace worn jets and seals, and reset floats to the correct factory measurement. We then bench sync the carbs so fuel is delivered evenly across all cylinders. The result is strong, clean acceleration all the way through the rev range with no misfires.
If your bike struggles at higher revs, don’t risk engine damage by ignoring it. Book your carburettors in for a professional clean and rebuild and enjoy full performance the way it was designed.
