CBR929, 954 plug fouling problems

If a cbr929rr or cbr954 Fireblade fouls the #1 and #4 spark plugs, the fault may be an internal leak in the fuel pressure regulator on the fuel rail.

The fuel passes past the diaphragm and into the 2 vacuum hoses that are fed from #1 and #4 throttle bodies - adding too much fuel, especially at low rpm.

Pull the fuel pressure regulator's vacuum line and see if fuel leaks under pressure - BE CAREFUL of fire!

Thanks to:
Solo Moto
Greenwich, CT
203 531-5252