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DHM Performance ECU Flash for the 2022+ Honda Grom / Monkey

Type: ECU
New ECU Core
We were the first to flash the 2022 model Grom / Monkey back in 2021 and have since made significant progress dialing in our tunes for this platform. With extensive dyno and track testing you can expect nothing but the best from DHM when it comes to tuning your factory ECU!

Two ways to order: Select to send your ECU in and we will flash it and send it back OR Select to purchase a new core preflashed ECU.
Does not work on European, Japanese or Korean spec bikes. 
The 2022 factory engine runs lean once you've modified it, and the ignition timing maps are not optimal at all from the factory. By modifying dozens of maps in the ECU, our calibrations are not only safer than stock, but also more powerful, win-win!
The DHM ECU Flash modifies the following:
  • Fuel mapping - we remap the entire fuel table to help your bike run safer while also making more power than the factory mapping. We can maintain factory fuel economy at part throttle while also making sure the bike runs safely and effectively under load. Fuel mapping is essential to keeping engine temps down.
  • Ignition timing - we modify all spark angle maps to increase throttle response and power while keeping temps down. This can also help with fuel economy at part throttle, while allowing gains across the board when under load. We've altered the timing to eliminate the factory power dip around the 5,000rpm mark.
  • SOI - Injection timing is modified to make sure that fuel is delivered at the most precise moment to increase efficiency and power. 
  • EOT Tables - We alter engine operating temperature tables to make sure the ECU compensates for high engine temps. This failsafe helps prevent engine damage when extreme temperatures occur.
  • Optional - Tip sensor delete and Cold start delete
Map Options:

  • Exhaust Only: For bikes that are bone stock other than an aftermarket exhaust system
  • Stage 1: For bikes that have an aftermarket intake and exhaust installed
  • Stage 2: For bikes that have an intake, exhaust, and aftermarket camshaft installed 
  • Stage 3: For bikes that have intake, exhaust, camshaft and our DHM piston installed
  • DHM 149cc Big Bore: For bikes that have intake, exhaust, the DHM 149cc kit, DHM S1 camshaft, and Honda PCX150 fuel injector (16450-KZY-701)

***Each tune is catered to your exact modifications (intake, exhaust and cam brands, etc.) After checkout you will receive a link to an online form that will ask for your bike's exact setup so we can tune it accordingly.

We have maps for nearly every combination of intake, exhaust, and cam, and are currently updating our library daily. 
Our S1 cam for the 2022 model can be found HERE.

Our stock bore high compression piston can be found HERE

Our big bore kit can be found HERE.

If you are looking for packages that include a cam and/or piston, you can find those here:




  • Orange: Bone Stock
  • Green: Stock with Yoshimura Exhaust
  • Purple: Yoshimura Exhaust and DHM Flashed ECU
  • Red: Yoshimura Exhaust, Intake and DHM Flashed ECU

  • Blue: Stock 
  • Green: Chimera Intake, Yoshimura Exhaust, DHM S1 Camshaft, DHM Tune




Customer Reviews

Based on 233 reviews
Brian Burkhart

Sounds better. Bike Screems thru the gesrs like a Rape Ape for a little bike. Alot better than stock. I got it to top speed 65
I weigh 230lbs. I think that's pretty Great for a little 125!!. Very Happy and recommend it to all Grom owners. Thanks again to DHM for all there help and hooking me up with the right stuff and it fits and works Great. Thanks again Brian from OHIO

Christopher Neiner
Got it back quick

I received my ECU back within 2 days of them receiving it. I have no complaints.

Kamuel Rodriguez

I'm loving it. It's amazing!

Chris Hewell
Best mod

This combined with the s1 cam really woke up my bike.


This is amazing what difference the grom came alive finally power at all times. Thank you everyone at DH Motoring