Harley-Davidson FXR Suspension

Pro rider and motorcycle instructor Alexander Andreev brought his new old motorcycle Harley-Davidson FXR 1994 to be customized and prepared for extreme riding. Iconic and unique, it's the lightest Big Twin Harley and the most rigid frame. The engine has already been rebuilt, so it works well. The carburetor problem hasn't been solved yet: it floods during long wheelies. If we can't fix it, the engine can later be replaced with a modern fuel-injected one, since the frame allows it.

The first thing we need to do is to replace the suspension, as it determines efficiency and comfort the most. Many things depend on it, such as the braking distance (the fork's ability to keep the wheel pressed to the road), the dynamics during fast acceleration (shock absorbers compression when the rear wheel is loaded quickly), control when passing obstacles (bottoming out the suspension can lead to an impact, wheels lifting from the road surface, the handlebar being knocked out of your hands), the motorcycle stability at high speed (the fork and shock absorbers shouldn't swing the motorcycle at speed or on bumps), stability in leaning when cornering (swinging suspensions can lead to the wheel unloading and a crash).

Stock suspension is not suitable for stunt riding as the fork bottoms out when landing after a wheelie. It's impossible to achieve effective emergency braking, because the fork dives instantly and rebounds when pressing the brake lever sharply. Shock absorbers don't provide an even loading on the rear wheel when drifting; they swing the motorcycle changing the load and grip of the rear wheel. Jumps and flat tricks will quickly kill not only the suspension, but the entire motorcycle, because the impact energy will be transferred to the rims, bearings, frame, and swingarm.

After test runs, Alexander settled on a rear shock length of about 14 inches under load with the rider. This means the shock absorbers should be about 15 inches. The longer the shock absorbers are, the greater the travel and energy capacity. Also, long shock absorbers will increase the ground clearance, which will allow the rider to lean the bike more while cornering. Longer shock absorbers will at the same time raise the fender to prevent it from rubbing against the wheel. Alexander made a mistake with the fender configuration, so short shocks can't be fitted — he didn't mention that in the video.

Shock absorbers

The only 15-inch shock absorbers we found were the Progressive Suspension 470 series. They fit on the FXR with some modification: the bushings must be shortened by 1 mm so that they can fit into the mounts on the swingarm — we didn't show this in the video. What's good about these shocks is that a floating piston is used instead of a rubber bulb in the reservoir — it's more reliable and easier to maintain. For compression, a separate valve with its own stack of washers is used — this allows you to tune high- and low-speed compression independently of rebound. The manufacturer gives a lifetime warranty on their products.

For normal use, we always recommend installing the shock absorbers 0.5–1 inch longer. This will practically not affect the motorcycle height and weight distribution, but it will increase the travel and energy capacity of the rear suspension, which is very useful. The manufacturer doesn't really matter, the main thing is that they are monotube (oil under pressure due to a chamber with compressed nitrogen). On such shock absorbers, the oil doesn't foam, and they continue to work even under intense load. When air bubbles appear in the shock absorber, it's like an air-filled braking system: the lever becomes soft and the brakes stop braking. The same happens in the shock absorber when cavitation occurs: the rod moves inside the damper without resistance.

Fork

Elongated shock absorbers require the fork to be lengthened, especially when doing a wheelie. For a wheelie, it's better to load the rear wheel as much as possible, that is, raise the steering column. This can be done by installing a wheel with a larger diameter or a longer fork.

We are lucky that Legend produces Axeo cartridges for a 39 mm fork with a high top cap, which is needed for through-shaft technology. This cap allowed us to lift the front of the motorcycle as we need.

In the video, we replaced the original fork with a Sportster 2004 Roadster fork because it has a caliper mount on both fork legs. This fork has longer inner tubes, so you have to install tubes from a Sportster 2003 or use an additional top-out spring (for example, OEM one with top-out spring from the Legend kit).

Even though all 39 mm forks are similar, they all have different lengths. Even forks with the same inner tubes can have different lengths and travel, due to different cup depths at the bottom of the outer tube. Therefore, we recommend buying cartridges for a specific fork. Especially since the oil level is matched to specific cartridges and forks. Since Legend's manuals give only the oil volume, not the level, it's impossible to know how much oil we need to pour if the cartridges and fork are from different models.

You can buy Harley-Davidson suspension and get advice in our store. We are official dealers of Legend, Progressive Suspension, Bitubo, Ohlins, Hyperpro, RaceTech, Drag Specialties.