Honda Grom
FMGV S260802C

These instructions give an overview of the installation of the Race Tech Gold Valve Kit into the MSX125 Grom.  This is an advanced installation that requires special tools even if you are only changing Fork Springs.

The stock forks are way underdamped and undersprung and are much better with a bit more travel. The Gold Valve Shaft Kit addresses all these areas (more travel too).

In stock form both legs are identical. When this installation is complete Compression damping will be created in one leg only while only rebound will be created in the other.

Before working on the forks go to the DVS-Digital Valving Setup and printout your personal setup sheet. Use the Access Code on the first page of your instructions. Compare the pre-valved settings with the recommended ones and determine whether you need to change from the standard valving.

These instructions show the simplest installation and will not show complete disassembly of the Fork Seals and Bushings. If this is required for service the Dust Seal and Circlip should be removed, then the Fork should be "slide-hammered" apart. Seal installation requires a 31mm Seal Driver.

Special Tools Required:

TFSH 31 Shaft Holding Tool
TMWA 14 Allen or Deep 14mm Allen Socket
Propane Torch or Heat Gun


D1 - Remove the plastic beauty cap. It just pops off. This exposes the Allen Bolt that attaches the damping rod to the cap. If you'd like to you can break the Allen Bolt loose at this time.

D2 - Hold the Fork Tube in a Vise with soft jaws (TMVJ 065) or leave it clamped in the triple clamps with the top pinch bolt loose.

Remove the Fork Cap. (In case you were worried this is a really cool wrench make by Knipex. If you don't have one of these you might consider it. It is not a pipe wrench.)

D3 - The Allen Bolt is tapered. This is to aid assembly.

D4 - Remove the Cap,

D5 - Remove the Rubber Bottom-out Bumper,

D6 - Remove the Bottoming Plate,

D7 - and remove the Clip.

D8 - Pour out the old oil and dispose of properly. To get the oil out of the inner chamber it helps to pump the Rod.

D9 - Extend the Fork Tubes all the way. This will expose (4) holes in the Inner Fork Tube.

D10 - This is the TFSH 31 Fork Holding Tool. If you look closely you can see a pin in the tool. Line up and insert the pin into one of the holes.

D11 - Use the other half of the tool and ...

D12 - firmly clamp it in a vise.

D13 - This is where it gets tricky. You must heat the Fork Bottom to 350ºF at the height shown, all around the outside to loosen the locking compound on the threads. Too much heat will burn the paint. Way too much heat will melt things and change them in ways you don't want.

THIS FORK BOTTOM HAS LEFT-HAND THREADS! Use the original axle and unscrew in a clockwise direction (viewed from the top - I am pulling here).

GLOVES ARE HIGHLY RECOMMENDED so you don't burn your hands.

D14 - Done. Set it aside and please don't burn yourself.

D15 - Removing the Fork Bottom will expose the Plug on the bottom of the Inner Fork Tube. Note that there is a Face O-ring on the Plug that will need to be there on installation.

D16 - Use a 14mm Allen (or a TMWA 14 in a 14mm socket) to remove the Plug from the Inner Fork Tube. Regular right-hand thread.

D17 - The cap will pop up due to the spring preload. Remove the Washer and Spring and dump out any remaining oil.

D18 - The stock Damping Rod can be removed by inverting the Fork Tube.

D19 - Remove the stock Top-out Spring from the Damping Rod.


In stock form both legs are identical. When this installation is complete only Compression damping will be created in one leg while only Rebound will be created in the other.

If the pre-installed valving does not match your DVS Setup Sheet you will need to adjust the valving. Click here for detailed instructions.


A1 - Install the stock Top-out Spring onto the Gold Valve Damping Rod Assembly. If a valving change is required from the pre-valved settings according to your DVS Setup Sheet do it before installing the Damping Rod Assembly.

A2 - Install the Damping Rod Assembly into the Inner Fork Tube. We generally install the Rebound Damping Rod in the right Leg but it really doesn't matter.

A3 - Re-clamp the Fork Tube in the Vise. Install the new RT Hi-Performance Spring. RT Springs are a must as the stockers are both too long and too soft.

A4 - Calculate preload.

First measure the Distance to the Spring from the top of the Fork Tube (shown).

The Plug is 16mm long. If the measured Distance to the Spring is less than 16mm the difference is the Preload.

The Preload should be between 5 and 10mm. If you need to add Preload insert Preload Washers provided (or use the stock ones) between the Spring and the Plug.

A5 - Tighten the Plug into the Fork Tube to 30 ft-lbs (41 NM). No need for Loctite here.

A6 - Clean the thread and use Hi-strength Loctite (provided). Make sure the Face O-ring on on the Plug and install the Fork Bottom.

Remember - reversed left-hand threads.

A7 - If you have a TMWA 14 Allen Wrench, clamp the the Fork Bottom in Soft Jaws in a Vise.

A8 - Screw the Fork Tube into the Fork Bottom by hand. Then insert the TMWA 14 into the bottom.

A9 - Use a 14mm socket and a...

A10 - Torque Wrench. Turn clockwise (viewed from the top) as the Fork Tube is a LEFT-HAND THREAD.

Clockwise because the Fork Bottom is clamped in the Vise and the Fork Tube is being turned beneath it. This may be opposite of what you think initially. Torque to 50 ft-lbs (68 NM).

A11 - Invert the fork. Install the Clip,

A12 - Install the Bottom-out Plate,

A13 - Install the Bottom-out Bumper,

A14 - and the Cap.

A15 - Install the Allen Bolt. A drop of Loctite on clean threads works here as well.

A16 - Tighten it to 15 ft-lbs (20 NM).

A17 - Measure the correct amount of USF-05 Fork Fluid according to the DVS - Digital Valving Search.

A18 - Pour the Fluid into the top of the Fork Tube. Pump the Damping Rod with your hand to draw the oil into the inner chamber. Tighten the Fork Cap and install the beauty cap.

A19 - Most importantly, carefully install the Race Tech stickers.

A20 - Stock is on the left. RT is on the right. Notice the stylish sticker. The modified forks are 20mm longer. This has geometry benefits and increases bottoming resistance as well.

Mount the forks on the bike and enjoy!

We have a variety of G3-S Custom Series Shocks for the Grom. Everything from a simple and relatively inexpensive IFP Shock to Piggyback with Compression and Rebound Adjust to Remote Reservoir with Lo and Hi-Speed Compression Adjust. Every shock is custom setup and guaranteed to please. Color choices are available too.