Honda ECU
Flashing

Why flash a Honda ECU?

Hondas are known for smooth, refined engines, and much of that refinement comes from conservative calibration: lean cruise fuelling, soft throttle response and limits set with emission tests in mind. Flashing lets you keep the reliability and remove the compromises, especially once the exhaust or intake has been changed.

Honda ECU families

• Keihin RH850 (Honda CAN), 768 KB: the small-capacity range: CB125, Grom (MSX 125), Monkey, CRF300L and Forza 350.
• Keihin RH850 (Honda CAN), 1 MB: the 500 and 650 twins and fours: CBR500R, CB500X, CBR500F and CBR650R.
• Keihin RH850 (Honda CAN), 2 MB: the larger bikes: CBR600RR, CBR1000RR, CB750 and CB1000 Hornet, CRF1100 Africa Twin, CMX1100 Rebel, NC750 and XL750.
• Keihin M32R: earlier CBR600RR, CBR1000RR and CB1000R, over K-Line (OBD2), with a bench (BDM) option.

All the RH850 ECUs are read and written through the diagnostic connector with a Tactrix OpenPort 2.0 or CANable. Check the table above for your exact model and year.

What riders change on a Honda

• Fuelling at small throttle openings for a crisper response.
• Maps matched to an aftermarket exhaust or air filter.
• Ignition timing for the fuel you run.
• Rev limiter and fan temperature.
• Settings for track days and off-road use on CRF and CBR builds.

Flashing a Honda, step by step

1. Put the battery on a charger.
2. Connect your interface to the diagnostic connector.
3. Read the ECU and save the original file.
4. Edit the maps or load your tuner’s file.
5. Write the file back. MotoFlasher corrects the checksum.

Frequently asked questions