Can You Really Do Your Own Suspension?
For years Race Tech has offered Gold Valve suspension kits that it claimed would allow folks to fully modify their own suspension at home. We were curious whether the claims were true, and if they were, does it make sense to do your own suspension? We ordered up the parts and then installed them with the help of my better-equipped-than-normal home garage. Some riders are more likely candidates for modified suspension than others. For our test we chose DR and Mini Rider test pilot Sean Foos and his 2009 Honda CRF250R. Foos is 5'10" but only weighs 120 pounds, so modified suspension is mandatory for him. Before we started with the Gold Valve conversions, we installed Race Tech springs in rates suggested by the spring rate calculator on www.racetech.com. With Foos being so light, the suggested rates were significantly lighter than stock. In spite of the softer springs, the bike was still too busy and harsh. What suspension experts like Race Tech said was true: the suspension needed internal modification for such a light, fast rider.
Race Tech felt that changing nearly every tunable aspect of the suspension was the best option for a rider who is 30 pounds below the Honda design envelope. That meant Gold Valves for compression and rebound in the fork, changes to the mid-valve shim stack and softer-rate pressure springs in addition to the general clicker settings and oil level. In the rear we installed a Gold Valve and new compression and rebound shim stacks, with (as in the fork) Race Tech suspension fluids.
Our original plan was to have Foos do all the work himself, and he has never done more than change a fork seal. It turned out to be a little ambitious with the current how-to videos that RT has. The company is currently making all-new videos that should make the job easier for those less experienced. It ended up being a three-way collaboration with Foos and I working together with the RT help line. I'm pretty comfortable with fork rebuilds, but I have only done a few rear shocks. You may have many of the required special tools if you service your own suspension, but if you are a suspension newbie, you will need some tools. This isn't a step-by-step guide, just a chronicle of the experience.
When we started we had this pile of parts, springs and suspension components. To begin with we changed out the springs for lighter spring rates. Since Foos is so light, the rates were softer than the softest spring Honda offers. Foos tested for a couple of weeks with the softer springs before changing the shim stacks and damping pistons.
All of these parts (plus springs and suspension fluid) are used in the fork modification. The larger Gold Valves are for the compression side of the fork, and the smaller ones are the rebound/mid-valve control. The rebound pistons require disassembling the cartridge and removing the cartridge rod. The pressure springs require disassembly of the compression end of the fork.
We began by removing the Twin Camber cartridge from the fork and dumping the outer chamber fluid. Next we loosened the base valve with a cap wrench and a 32mm (or inch and quarter) socket. Then we used the socket to extract the base valve. A wrench will not work well for this job.
To remove the valve shims and compression damping piston, you must remove a staked nut. We didn't want to get carried away with power tools, so we filed one, but found that a bench grinder does a much nicer job. Just don't go crazy. You must put a nut back on the same threads, so you only want to grind away a small amount of material.
Next you have to clean all the parts and build the shim stacks. Race Tech has a code on each Gold Valve box, and that code either opens up the web site, or an e-mail is sent to you with all the set-up information. You need a tool to measure the thickness and diameter of the shims to do the job correctly. This caliper was under $20 at Harbor Freight (
www.harborfreightusa.com/dirtrider).
Even if you rebuild forks, you may not have this $59.99 shaft-holding tool. RT has several, and you will need one to hold the cartridge rod while you work on the rebound and mid-valve piston and shim stacks. You cannot afford to mar the surface of the rod, since it must pass through the cartridge seal. The shaft holder fits in any vise.