Koso 170cc Big Bore + 4 Valve Head (Complete Kit) 2014-2021 Honda Grom & 2019-2021 Honda Monkey 125
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About Koso 170cc Big Bore + 4 Valve Head (Complete Kit) 2014-2021 Honda Grom & 2019-2021 Honda Monkey 125
Want arm stretching power for your Honda Grom or Monkey?
This complete top‑kit is the perfect add‑on for all horsepower enthusiast looking for performance ! It includes : a 170cc ceramic coated cylinder, forged piston, performance camshaft, bearing, rocker arms, 4 valve cylinder head, intake manifold, gaskets, and more. All parts are made from High‑quality components for reliability and durability that allow you to put your mind at ease and ride with confidence!
We've packaged all the hard to source supporting items, such as Koso 34m throttle body, fuel injector & adapter, and the correct spark plug into one package for you. Hold on tight!
KOSO high flow oil pump HIGHLY recommended.
MNNTHBX Mtake will not work without a custom adapter. Custom intake required to attach to the 34mm throttle body, and the intake does not come with this kit.
Either a aRacer tuner or DHM ecu flash is required
*Does not fit 2022+ models*
5 reviews for Koso 170cc Big Bore + 4 Valve Head (Complete Kit) 2014-2021 Honda Grom & 2019-2021 Honda Monkey 125
nema741 –
Perfect upgrade on the grom! Absolutely love this on mine!
clint (verified owner) –
Looks great, just needs one sharp edge around combustion chamber smoothed out & installed.
Ryan –
Will this fit a 2022 monkey?
kevin estep –
No. As listed, it’s for the 19-21. Different engine.
David Fullington –
Does this need an oil cooler in the system? Is one provided? Recommended?
kevin estep –
Not all application will require it, but many will. It depends on the usage and environment…
David Fullington (verified owner) –
I bought the 170 complete kit for my 2021 Monkey and ended up selling the Monkey and buying a 2024. This kit is still in the box never used. Is there no way to utilize this on my new Monkey? I wanted the 5 speed to allow me to rev the engine less when going fast due to the 5th gear. What can I do to get some value out of my 170 kit and get more performance out of my new Monkey?