Although we installed our valves in a fully-equipped shop, we're going to assume that you don't have access to things like 1/2-inch air impact guns, so where appropriate, a "shade tree" alternative is provided.
By the same token, while we're installing our kit on an Electra Glide, the basic procedure is virtually the same for all bikes, so the following pertains to a majority of damper rod forks. I say 'majority' only because I don't want someone with a 1947 Vard telescopic fork conversion on their Indian Chief sending me an irate e-mail because Race Tech doesn't make a Gold Valve to fit.
Once the spacer has been cut, set it aside for a moment and pour in the fork oil, using the OEM's recommended viscosity and height (If there's any question contact Race Tech's service department and they'll provide a recommendation.)
Work the fork through a few compression/rebound strokes to bleed out any trapped air and recheck the fork oil level. Install the fork spring and preload spacer, double check the preload height, then install the fork cap.
From here on in it's just a straightforward reassembly of the front end, although I'd be remiss if I didn't provide the obligatory warning to work patiently, consult the shop manual as far as bolt torques go, and be sure to apply locking compound wherever it's called for. Remember this is the front end we're working on, so if something comes loose or is improperly installed it's going to get ugly quickly.
Tuning Notes
Suspension modifications are just like any other type of elective moto-surgery in that, if you cross the T's and dot the I's in accordance with the manufacturer's instructions you're pretty much on the path to a harmonious outcome, and that's particularly true in this instance. In my experience, Race Tech's recommended settings are usually right on the money. However, in some cases, fine tuning may be required, or you may just want to experiment and find out what happens when you add more or less preload to the valve spring.
In either case, my advice is to work slowly and methodically, making only one change at a time. It's easy to lose your way when working on suspension-"let me think, did adding fork oil make the fork more responsive or just mushy?"-so record each change and your impressions of what that change did to the bike so you don't get confused. If you do get bollocksed you can always return to the base settings so no need to be overly cautious either. Suspension tuning can be time-consuming, even with something like the Gold Valve, but in the end it'll be well worth the effort.
Low (damper) Speed
When the fork compresses, oil flows through the center of the OEM damper rod into the Gold Valve. As long as damper speed is low, flow is controlled by a small bleed hole in the Valve's damper plate. This provides a smooth, firm ride over gentle bumps.
High (damper) Speed
When something big whacks the fork, like a sharp or square-edged bump, it increases the suspension speed, causing the oil velocity and pressure to rise until it overcomes the Gold Valves check plate spring preload. This forces the check valve (plate) off its seat, which allows the oil to bypass the bleed hole and flow directly through the valve's ports. The fork is no longer bound by the physics of velocity-squared damping, so it behaves in a more progressive manner. The spring's weight and preload determine the GV's high-speed compression damping
Rebound Damping
Rebound damping is controlled by the fork's OEM rebound damping holes and check valve. However, since the Gold Valve doesn't restrict return flow and the stock compression orifices are now radically larger, the returning oil has an easier time reaching the rebound orifices, so cavitation (an influx of air) on the return side-always a potential problem when an orifice-controlled damper is overworked-isn't an issue.