So rather to my surprise, there appears to be a niche for folks who use R125s for racing series, who have to comply with series/class rules, and where (for example) fitting an aftermarket ECU is not permitted, but a piggyback+oem ECU is ok.
So if you’re chasing every last drop of speed to fend off those pesky suzukis whilst wanting to stay within your class rules, there are certain things we can do with an OEM ecu which you probably wouldn’t do on a regular street bike, but would be ok with a more built engine…such as raising the RPM limit, ignition timing tweaks etc.
Whilst I’m planning on moving away from an oem+piggyback setup myself in favour of a drop-in replacement aftermarket ECU, I do currently run a modified oem ecu + piggyback (PCV+autotune) setup in my main ’08 bike with its rebalanced internals, and that merrily screams all the way to 11.5K rpm.
Modifying the oem ECU is quite laborious and a bit of an arcane process, which (for street bikes anyway) makes it largely a less preferable option to a replacement/aftermarket ECU which can be easily tuned from a mobile device over bluetooth.
Street bike engines have usually also not been prepared to the same degree as race engines, and as such race engines may be able to handle things like a higher RPM limit or more timing more comfortably because they’ve been equipped with uprated valve springs, different fuels, adjusted internal balancing etc.
So if you find yourself in the position of needing some little adjustments to your oem ECU, then please get in touch to discuss your requirements.
Whilst I normally like to share as much info as I can, unfortunately the nature of racing means I can’t really give examples of work I’ve done, but if you’re needing a little additional RPM or other specific changes to the oem ecu, please do drop me an email.