Suspension school is in session...
Suspension school is in session and Race Tech is showing us how to beef up some stock suspenders.
Riders modify their suspension for many reasons, whether it’s in pursuit of better ETs at the drag strip, quicker lap times around a race track or in search of a supple ride. Sometimes it’s necessary for a physical reason—weight.
In the past we’ve covered several projects that took a stock-height bike and lowered it to better fit a person of shorter stature, but what about those individuals who simply outweigh the stock suspenders? What are they to do when their sportbike wallows and sags under the load, not because the parts are worn out, but simply because their weight is outside the limits of the stock suspension? Modify it, of course.
When a local rider brought his 2005 GSX-R750 by our office complaining of suspension problems, it only took one glimpse at his size for us to immediately understand why. Standing a few notches over six feet tall and tipping the scales on the north side of 240 pounds meant he was too large for the stock suspension setup. Even with the settings tightened the forks would bottom while on the brakes (and we’re not talking race track braking, but rather a semi-aggressive street stop). A stock sportbike suspension setup is designed for a 150-170 pound rider, not someone who’s well over 200.
Since the GSX-R750 had amassed nearly 30K miles we decided to start with a full fork revamp. Along with new fork seals, dust seals and Race Tech oil, the crew at RT also added a Gold Valve rebound valve along with a Gold Valve compression valve. These golden goodies not only offer more compliance over slow-speed bumps, but they’ll eat up the bigger stuff as well. While the techs at RT were at it, they also added some burly 38x36x250 1.0kg springs and even crosshatched the inner tubes to ensure the oil would adhere to them long enough for proper damping. Since oil will run down a smooth tube faster than a rough one, crosshatching the surface makes the oil hang around a little longer.
Although you can buy the parts and do the work yourselves, we thought it best to leave it to the pros, so we sent the forks to Race Tech.
Follow along as the suspension gurus show us how it’s done, and check back next issue as we address the sagging rear shock and finish up with a full ride report. ssb
 Race Tech started the...
 Race Tech started the fork revival by disassembling each leg. First came the oil seal, and then the dust seal followed by the inner and outer bushings. The inner bushings will be crosshatched to better retain the oil, since the oil acts as the damper (the fluid sits in the hatches and acts as a damper instead of sliding down what was once a smooth surface).
 A touch of red Loctite...
 A touch of red Loctite is used on the Gold Valve rebound valve after the rebound stack is reworked. Remember folks, only a dabble, since red is awfully sturdy.
 Something old and something...
 Something old and something new. Here’s a peek at the stock valving against the Gold Valves.
 The stock compression...
 The stock compression valve must also be disassembled in order for the Gold Valve unit to replace it.
 With all of the golden...
 With all of the golden goodies inside, it’s time to install the oil and dust seals along with the inner and outer bushings.
 Next up is some Race...
 Next up is some Race Tech Ultra Slick fork fluid. It’s not just any 50-weight motor oil, but rather suspension-specific fluid that’s either a 5W or 15W depending on the application (we used the 5W).
 Once the legs are filled...
 Once the legs are filled with the appropriate amounts of fluid, the fork cap, preload spacer and spring are then secured into place and everything can be reinstalled.
Race Tech fork rebuild and upgrade
Fork rebuild and crosshatching (labor) $140.00
Gold Valve (compression) $169.99
Gold Valve (rebound) $159.99
38x36x250 1.0kg springs $109.99
Showa dust seal $19.98
Showa oil seal $21.98
Ultra Slick fork fluid $14.99
Special thanks to the crew at Race Tech for all of the help with this article.
Next Month: We address the sagging rear end.