Honda Grom Stage 3 | DHM Piston, ECU Reflash, and TB Camshaft

DH Motoring

Sale price $275.00 Regular price $335.00

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Customer Reviews

Based on 23 reviews

Everything installed fairly easy with a couple of YouTube videos, if I can, I’ll send another review in the spring when I put some miles on it

Stage 3 is a must!

I installed this kit with my existing intake and exhaust and the grom didn't go to much better little did I know my baffle was still in.. so I removed it and oh my you notice a big difference, so far have done 800k no problems, wind and hills have very little effect on riding, hasn't givin more top speed but I can sit on 100kph comfortable so again I recommend for sure


Took about an hour to install. Filing rings took the majority of the time. Very straight forward. Cannot wait to get a clutch in and hit the drag strip.

Same top speed as stock but more pep

Installed the stage 3 kit and did a proper break in. The bike runs great and has great mid to high rpm power now. The low end is definitely slower but thats due to the style of cam. What i was really hoping for was a higher top speed. I can max out at 55-57 mph in a full tuck. Same as stock top speed. Im 6'1 and 180 lbs. my only disappointment was i needed more top speed and didnt get it.
But i love the added get up and go!
Id still recommend to everyone tho. Especially lighter weight riders

Amazing upgrade

This kit makes the grom what it should have been from Honda. It doesn’t make the grom something it isn’t but it makes it fast for a Grom. The full RPM range is usable now and the upper RPM range is the most fun- like any sport bike. It really wakes up over 7,000 RPM which is awesome because stock the Grom falls on its face over 7,000 RPM. Only time will tell how reliable it is in the long run but I’m happy.

The DH Motoring Stage 3 Package includes the following:

DHM High Compression Stock Bore Piston
TB Parts Camshaft
NGK CR9E Spark plug with spacer

Honda Monkey Stage 3 kit is available HERE

Combined with your aftermarket intake and exhaust, this is the most you can get out of your Grom without doing any head work. After dyno testing we were repeatedly seeing 13.5hp at the wheels (SAE) run after run! The Stage 3 package makes more power than a stock Grom at every RPM and double the horsepower at 9000+ rpm! 91 octane fuel is absolutely required. Any fuel with a lower octane rating may result in engine damage!

You can choose to receive a preflashed ECU instead of sending yours in. You can also choose to receive a new cylinder matched to the piston if yours is worn. 

This product page is for customers that do not currently have a DHM flash or cam package. If you already own our reflash or cam package, you can purchase the Stage 3 Upgrade HERE.


Install video: