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DHM S1R Camshaft for the 2022-2024 Honda Grom / Monkey


Our S1R adds a bit more duration to our S1 cam which helps with top end power! When used with our 149cc big bore kit, there is little to no low end loss and performance is boosted throughout the mid and top RPM range. When used with the stock bore, you'll see a minor power loss under 5,500rpm with similar power up to 6,500 and then more power from then on up to the rev limiter. 

  • Increased duration over our S1 cam provides more mid and high RPM power to pull higher top speeds with a strong mid range powerband. 
  • No extreme lift numbers maintain compatibility with the stock valvetrain.
  • Fits 2022-2024 Honda Grom / Monkey
  • Set valve clearance to .005" on both intake and exhaust

ECU Flashes are in progress, currently we only have flashes for the following setups. Every other setup will require an aRacer to tune properly. 

**The tune for our S1 camshaft is not compatible with the S1R cam. If you have the S1 cam and decide to swap out to the S1R you will need an ECU update, available HERE

ECU Flashes available for:

  • DHM 149 Gen 2 with S1R cam, Koso 34mm throttle body kit with AvailMS adapter, PCX150 injector, aftermarekt intake, aftermarket exhaust.
  • Stock piston, DHM S1R camshaft, aftermarket intake, aftermarket exhaust

S1R Dyno Data -

Red: Stock piston, aftermarket intake, aftermarket exhaust, S1 Cam
Yellow: Stock piston, aftermarket intake, aftermarket exhaust, S1R Cam



Blue: DHM 149 Gen 2, S1R Cam, Koso 34mm TB with AvailMS adapter, PCX150 Injector, Aftermarket Intake, Aftermarket Exhaust
Brown: DHM 149 Gen 2, S1 Cam, Koso 34mm TB with AvailMS adapter, PCX150 Injector, Aftermarket Intake, Aftermarket Exhaust

s1r camshaft dhm big bore 149cc kit dyno

Customer Reviews

Based on 3 reviews

Amazing product

Justin Doughty
2024 Grom S1R Cam: Update

I have put about 1k miles on it now. I can hold 68 up hill and I have repeatedly hit 77 mph at 9k rpm. (GPS confirmed). I still love it and would buy again.

Justin Doughty
2024 Grom S1R Cam & Tune

This cam really woke up my stock 125cc. It gets through the RPMs faster and just feels like it has more pep. I've already put over 200 miles on it and it was worth it. Cruising around at about 6-7k rpm it still feels about the same as stock, but when you get past 7k it comes alive. So at about 55 to 60 mph up hill in 5th at 6500 ish, I still have to down shift to 4th, but can ride 4th up and out to 63 mph now. I still don't know what it will top out at yet, but I have hit 71 and feel like it could go up several more mph if I had better roads to try it on. I am betting when I finally do the 149cc BBK they will pair together amazingly and that will give it the extra torque it needs to do everything I want. When I first installed it, I did have to adjust the idle up to keep it running, but now that the ECU has learned, it idles just fine. Totally worth it, and I would buy it again.