Here you'll find a comprehensive kit containing nearly everything you need to big bore your 2022-2024 Honda Grom (You'll need your own aftermarket intake and exhaust and we do have options linked below). By purchasing this comprehensive kit we make it as simple as possible to install by pre-gapping the piston rings before shipping.
Includes:
DHM 149cc Forged Piston and Cylinder Kit
DHM S1 Camshaft
Kitaco x DHM 5-row Oil Cooler Kit OR Drow Sports x DHM 7-Row Cooler
High flow Honda fuel injector
AvailMS or MO Power Crankcase Vent Kit
NGK CR9E Spark Plug
DHM ECU Flash Service
Other Requirements:
Premium fuel (at least 91 octane, 93 is even better)
Quality synthetic oil of 10w40 weight or 20w50 for warmer climates
Base pricing requires you to mail your ECU in so we can program it. Once we receive it we'll flash it and send it back out with the kit so that it can all be installed together. You do have the option of purchasing a preflashed ECU as well for an additional $110.
If you already have your own aftermarket intake and exhaust setup, this kit is all you'll need. If you need an intake and exhaust, we do have a few options here:
Hi, received my bigbore complete kit. Installed in a few hours and was very easy. The power difference is very noticeable especially going up the hills. I highly recommend. Put about 70 miles on it the first day ran perfect except I had to adjust the idle. This kit is perfect for the monkey. It made it so much more fun. I can now ride some roads I was afraid to before with the traffic.
J
James LeBlanc
Professional
All good from start to finish.
Comunications,quality,assembly,a breeze to install.
No need to look any further than DHM for 149 cc all inclusive BBK.
J
John Rodriguez Jr
Wow
I had the stage 2 setup (intake, Dhm s1 cam, and exhaust) prior to the 149cc big bore kit. And wow, I can tell a difference in the power and torque this kit provides. This is such an awesome kit. I’m very satisfied with the 149cc big bore kit.