Yamaha FZR and FZS: Too Little Boost, Weak Supercharger?

On FZR and FZS the supercharger is a frequent suspect when power is missing. The app cannot report a supercharger failure directly, but M-JET DIAGNOSTIC shows you the intake pressure that gives the supercharger away.

How to check

• Compare intake pressure (kPa) and atmospheric pressure at standstill
• Test ride: record intake pressure, engine speed and throttle together
• Watch intake air temperature and ignition timing
• Check the fault memory for sensor and knock messages

What intake pressure tells you

If the engine builds up only ambient-level pressure at full load, the supercharger apparently does not deliver. That is a hint for a workshop to inspect the supercharger, not proof. It is known from forums that the supercharger clutch can suffer from sudden RPM changes. If intake pressure rises normally, you look for the cause elsewhere. That is a result too. Typical of a worn supercharger clutch is an engine that runs smoothly but hangs at about 5000 to 5500 rpm on the water while intake pressure stays close to ambient. According to forums a hand test of the clutch is unreliable; even a worn clutch can pass it. On the early SHO models (2009 to 2013) clutch problems were described; Yamaha revised the part later.

Related topics

• Yamaha FZR and FZS: Overheat Warning and Limp Mode
• Yamaha FZR and FZS: Knock Sensor Message and Intake Air Temperature
• Yamaha WaveRunner Power Loss: Finding the Cause
• Diagnostics and fault codes for your Yamaha model
• All Yamaha WaveRunner diagnostics topics

Everything runs via app over Bluetooth, for Yamaha WaveRunners from model year 2002 to today. Learn more about the M-JET DIAGNOSTIC for Yamaha WaveRunner.