This month I spent a little more time in the workshop than at the track with the 2025 Honda CRF250R. Being a bigger guy on a 250cc machine I am after all the power I can get. I have stepped down from a 450 on which I would normally ride in the lower parts of the rev range, but on the 250 I have to get used to revving the engine harder, as well as shifting gears more to keep the engine higher in the rev range.

To help with all of this I have fitted a GET ECU to the 2025 Honda CRF250R. Currently there is no GET ECU available for the 2025 Honda CRF250R so what I have had to do is get the 2024 model ECU and then remap it myself to suit the 2025 model.

This all sounds complicated, and without the tuning software and a dyno it would be impossible to get it perfect. To get it right I strap the bike on the dyno and fit an O2 sensor so I can monitor the air/fuel ratio. The 2024 mapping in the GET ECU will work on the 2025 model but due to the new air box and air filter the ’24 mapping is not ideal.

First I spent time to build a fuel map that has an air/fuel ratio close to 14 parts air to one part fuel. Then I experimented by adding and subtracting fuel at different parts of the rev range to see how the engine reacted. During this process I noticed that the engine reacted positively to removing the backfire screen from the air box – which is screwed in place – and cutting a larger hole in the air box cover. I also noticed the engine reacted better to a slightly leaner fuel map from the bottom but richer higher up in the rev range.

Once I was happy with the fueling it was time to experiment with the timing, which I figured needed to be much more aggressive with a more advanced curve down low that would then start to retard higher into the rev range.

Once I was happy with the mapping on the dyno it was time to track test the new setup. Quite often it is normal to change the mapping slightly once you get the bike on track but this map worked very well and no further changes were needed. I did however begin to make hard pack, mud and sand maps; using the GET wi-fi module the maps can be changed in seconds to better tune the engine to suit the terrain.

After sorting all the mapping out I actually organised a second injector that I am going to fit and tune for the 2025 Honda CRF250R. Again there is no bolt-on second injector kit available for the ’25 model CRF250R, so I am going to have to build and tune my own using the ’24 model kit from GET.

Check back next month and I will let you know how I get on with this and what sort of difference it makes to the overall power of the CRF250R.

 

2025 HONDA CRF250R

RRP

$13,799

WARRANTY

NA

DISTRIBUTOR

Honda Australia

INTERNET

motorcycles.honda.com.au

SO FAR

TOTAL HOURS: 5

MODS THIS MONTH: GET ECU, ODI GRIPS

MODS NEXT MONTH: SECOND INJECTOR