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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 2022-2025 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 242 reviews

The ecu got to me in Hawaii in 7 days. The product is solid, and provided a noticeable difference in my groms performance...She's a beast in all gears now not just 2nd...will come back to them after I add my new cam...

22 Grom exhaust only tune...

Honestly.. I feel no noticeable difference in power.. Could have done a few other upgrades for the $270+ I paid y'all that would have given noticeable power difference..
I've ridden over the suggested 30 miles after install as suggested, and 300 miles since install with zero noticeable difference.. and I can't even return it so now I'm out $270+..
Do I believe dhm's upgrades are worth it? Maybe for other upgrades but the exhaust only ECU tune is a bust for me..
Will I recommend dhm ? Not likely considering the reviews and videos I've watched of said performance update for exhaust only..
I do appreciate you reaching out and asking for a review and this is my honest review.. 49 years old been riding bikes since I was 3/4 years old..
So finally I give two stars out of five stars for shipping and communication only!!!
Thank you much 22 Grom Delaware

Joseph H
Everything came out fine

Sent my 22 groms ecu to get flashed and ordered the mmnthbx intake. Ecu came back flashed with no problems and intake as well. Great company and fast and smooth process.

Edward Allen
Great Service!

Second purchase from DHM and yet again, incredible service and fast shipping.

Stephane Daigle
Très heureux des résultats, au delà de mes espérances.

La programmation fonctionne très bien avec mon kit 150 Koso et Cam Koso. David a toujours répondu à mes questions et m'a bien conseillé. La moto pousse très fort tout le temps! Merci!