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Honda Grom Big Valve Head

Titanium Retainers
DH Motoring Big-Valve Honda Grom Cylinder Head

These heads are OEM Honda heads that have been modified with larger intake and exhaust valves. We assemble heads with low friction viton seals, dual springs, and offer optional titanium retainers. 

27/23mm valve size - This head has only been confirmed to work with DHM pistons and the TB 186 and Koso 170 pistons. If you would like to use it with a different piston you can send in your piston and we can modify it. This is the largest valve head that will work with the stock bore. 

**Each head includes a spark plug spacer required when running our heads.

        Info about our portwork:

DHM porting is an all out reworking of the intake and exhaust ports. The race port is aimed at maximizing high-rpm horsepower. In many cases we will cut the valve guides and raise the intake port to maximize efficiency. The chamber and shrouds will be modified as well. This is the portwork that we use on all of the race bikes. It has won multiple championships and is the only option if you want to have the most power possible from your 2v Grom head. 

**Allow 2-3 weeks for each head to be built before shipping

Customer Reviews

Based on 8 reviews
Anthony Ramsaran
Great Head

DHMotoring always building great parts.
Best head on the market

Chris mcguire
Bbk bv head

Greaty quality 👌 will by again

Adam Robinson
Holy crap!!

Im running the 186 kit. The kit pulled awsome lots of tourqe. but i wanted more high end power. So i went with this head matched with a 34mm koso Throttle Body. Oh man this head made a world of differnce in the way the bike rides. It pulls so hard down low and dont stop pulling. 16/32 gearing i cruise 65 easy barely twisiting the throttle . And David was again the best help. Very responsive and helpful on all my questions. No top speed run yet . Still kinda breaking in the 186! 5*s again for DHM.

Jon w.
Big Valve Head

Just installed the big valve head on 2019 monkey with the 2nd gen high compression piston TB Camshaft and Koso 34mm tb. I had the aracer mini 5 with af1. Bike has more grunt and holds at the sweet spots from 2nd to 3rd and 3rd to 4th. Worth the extra to get titanium retainers. Bike sounds and feels great!

John W
Davids the man

David is helpful and answers all questions. Would not hesitate to contact him about anything offered. Great customer service.