TB Big Valve Kit – Honda 125cc Monkey Grom MSX

TBparts.com is proud to offer a +1.5mm intake and +0.5mm exhaust valve kit for the Honda Monkey 125 and Grom (2021 and older models only). Our over sized valves are constructed out of EV8 stainless steel to provide superior strength and longevity over the factory valves. They are also lighter than the factory valves. Additionally, the valve profiles have been changed to yield better flow characteristics resulting in better performance.  With these over sized valves you get the best of everything as the stainless material will long out live the stock valves, the bigger size will yield more flow thus yielding more power, and the lighter design will help prevent valve float give providing the potential to rev higher and faster and it frees up horsepower used to open and shut the heavier stock valves.

Note:  This kit should be installed by a professional mechanic or shop that offers valve job service as the valve seats must be cut to accept the larger valve head diameters and valves sunk deeper to allow for overlap clearances.  Below are documents that include protrusion and install heights specs for both valves (click link):

intakevalveinstall

exhaustvalveinstall