StreetSweeperCustoms
NA · Pump Gas · Base File

CRF ECU Template Builder

Build your base file for the Honda CRF250L / CRF250 Rally / CRF300L / CRF300 Rally. For naturally aspirated engines running 91–95 octane with an aftermarket intake and full exhaust. Fuel corrections and feature configuration. It sets no absolute ignition timing — your ECU's own spark stands. Load the JSON into your standalone ECU software (aRacer, etc.) or hand it to your tuner.

1 · Your Build

This map is calculated for the stock injector. Fit a different one and every fuel number here is wrong by the ratio of the two flow rates — a smaller injector runs you lean, which is what holes pistons. See the modifications guide before changing it.
This base file is only valid for high-octane pump gas. No E85, no low octane.

2 · Features

Launch control
Secondary rev limiter for hard launches. −5° ignition, +10% fuel at the hold point.
6,500 RPM sits just below peak torque on a stock-displacement CRF — aggressive launch without looping or bogging.
Pops, bangs & flames (decel map)
Throttle closed (0–3% TPS) between 4,500–8,500 RPM: +15% fuel, −2° timing. Unburnt fuel detonates in the hot header on downshifts.
Bounce limiter (soft rev limiter)
A second, lower limiter you can sit on deliberately. On ignition cut the charge leaves unburnt and lights in the header, so it bangs and throws flame every time it catches.
Stays below the hard limiter, which is fuel cut and is there to protect the engine. This one never replaces it.

3 · Your File


      

    


    

      Read before flashing. This is a base file intended for motorcycles with a
      free-flowing aftermarket exhaust and intake. The fuel corrections were run on a dyno, so
      they are not guesses — but that was our bike, not yours. Altitude, fuel, wear and your
      exact exhaust all move the mixture, so verify AFR with a wideband on your own machine before
      extended use. This file sets no absolute ignition timing: spark on these engines is
      knock-limited on pump gas, and a timing table written for one bike is the fastest way to
      hole someone else's piston. Your ECU's own spark stands. Running the decel-flame map or an ignition-cut bounce limiter on a factory
      exhaust with a catalytic converter will destroy the converter. Sitting on an ignition-cut
      limiter puts raw fuel and a lot of heat through the exhaust valves and header — it is a
      party trick, not a way to ride. Emissions-related modifications may be restricted to
      closed-course / off-road use in your jurisdiction — know your local law.
      
    


    

      
      
      
We send your file here and let you know when the map is updated. No spam.