As you may know if you are following my blogs I decided that I wanted to improve the riding “feel” of my lovely little red CRF250L. I really like the way that 2018 Honda rides even as standard, SUCH a fun bike and the fuel consumption is amazing (better than 80 mpg, almost like my 50cc Giggle!). But I also noticed that the engine seemed to be very strangled and as a single cylinder that translates into “hiccups” on part throttle thus requiring very frequent gearchanges. I have years of experience with single cylinder bikes (Yamaha XT660, I had three, great fun) and I understood that this would be the case as the manufacturers are forced to set the engine very lean to comply with the latest noise and emissions regs.
So how to improve the ride? Several mods are required:
- Air intake. The airbox is below the seat and is not therefore getting much air flow. Also it breathes through a little plastic snorkel which further impedes air flow (and thus intake noise I guess). Well I removed the stupid snorkel and then I will fit a new BMC high flow air filter to replace the standard paper item. I may also drill some holes in the side of the airbox cover.
- Exhaust. I have an Arrow system on the way to replace the quite rusty and heavy OEM system. This will reduce the weight and allow the engine to breathe out better so I look forward to this! I have purchased several Arrow systems in the past and in general they are very well made and NOT too noisy. I hate very loud bikes but some noise is also a safety feature.
- ECU. The standard Honda ECU is mounted at the rear of this bike under the tail fairing, and it took some finding. The fuel settings are very lean indeed again to reduce the engine noise and to comply with the very strict noise and the emissions requirements. This is awful for a small single-cylinder engines so I had to decide how to overcome this and basically there are two methods: Purchase a “piggy back” system from Power Commander (or others) that fit onto the factory ECU and alow the user to modify the fueling. I instead chose the second method which is to remove the factory ECU and send it to a tuner to have it reprogrammed.
Well. I read about a tuner in the north of Italy so I made contact and Cristian Piasini of Piasini Engineering offered to modify my Honda ECU for 350 Euro. So I removed the ECU and sent it to him via courrier and within 10 days the modified ECU arrived home!! I then refitted the ECU to the bike and refitted the OEM air cleaner and still with the standard OEM exhaust I set out to try the bike.
Wowowowowowow. This now feels almost like a different bike to ride, really. It makes perhaps a little extra intake noise and power (that could be just my imagination, not sure yet) but the WAY it rides is so much smoother. She no longer “hiccups” at partial throttle and seems much more eager to pull away with almost no snatching. I made one or two overtakes that I would never have tried before simply because this bike now wants to GO!!!!!!. I also made a gentle offroad foray and that was great fun too, pics below.
I will soon test again with the BMC air filter and the Arrow exhaust and I will report back, but so far sooooooo much fun!!! Thanks Cristian!!!


