Honda’s XR500, XR500R & XR600R History 1979-2000.

Honda XR500 and XR600 machines 1979-2000

Over the years, Honda’s Open class Enduro racers have developed a legendary reputation for their power, reliability and versatility. Winning races in every environment from the mud bogs of West Virginia to the dusty deserts of Baja, Mexico. The XR’s multiple cross country and desert racing titles are a testament to the capability of Honda’s big four-strokes.

Started in 1979 as the XR500, the original Honda Enduro featured an advanced 4-valve “Pentroof” head and slightly odd 23″ front wheel shod with Honda’s exclusive “Claw Action” tires. With 8.8″ of travel in the front and 7’8″ out back and tons of torque, the original XR500 was a stump puller, but not much of a real racer.

Two years later in 1981, the XR500 adopted the “R” designation of the CR line with its first major redesign. The newly renamed XR500R maintained the Pentroof motor design but gained 1cc of displacement and a reed-valve (yeah, you read that right) to prevent backfiring. The chassis was also all-new and featured Honda’s first use of a single-shock rear suspension. Dubbed the Pro-Link, the new system was similar to those found on the all-new ’81 CRs and featured a rising rate linkage and single Showa damper. In addition to the shock, the new XR500R featured beefier 37mm front forks, powerful dual-leading-shoe brakes and much-improved ergonomics, The bizarro 23″ front wheel was also gone, but an almost equally weird 17″ rear was added to make sure tire selection would continue to be a pain in ever XR owner’s fanny-pack.

The 1983 season would see the next major redesign for the largest XR in Honda’s lineup. Literally reimagined from the ground up, the ’83 model laid the groundwork for what the XR would become over the new two decades. This is the first model to use Honda’s new RFVC (Radial Four Valve Combustion) head that combined a hemispherical combustion chamber with a super-narrow valve angles. This allowed the engineers to run a higher compression and extract a more efficient burn than the Pentroof design.

This new XR500R also moved to a “dry sump” configuration that carried most of its oil in the frame. This was done to alleviate much of the over-heating issues of earlier XRs. All-new bodywork once again updated the looks and massive new 43mm front forks matched the size of those found on Honda’s even more potent CR480R. One area where the new XR bested its motocross counterparts was in breaking, where is actually got the dual-piston front disc brake that the CR’s would have to wait one more season to adopt.

The next major XR milestone would occur in 1985, with the introduction of the all-new XR600R. Boasting a full 591cc, the new XR maintained the dual-carbs and RVFC head of the old 500, but boosted performance greatly through its whopping 93cc displacement increase. Once again, all-new bodywork freshened the looks and a new tank design slimed out its notoriously portly proportions. At a claimed 266 pounds (dry), it remained a heavy beast, but the new motor and redesigned chassis made it by far the best performing big-bore XR to date.

Three years later in 1988, the XR600R would see its last truly major redesign. Once again the chassis was revised to shed weight and offer more aggressive handling. The 591cc RFVC motor was also redesigned and featured a lightweight Nikasil coating for the cylinder for the first time. This change saved weight and improved performance by allowing tighter tolerances and improved heat dissipation. A new decompression system also made starting easier than ever. Further weight savings were achieved by dropping the finicky dual-carb setup and going to a far easier-to-tune single 40mm unit. Stainless steel headers and slick new bodywork once again updated the looks on Honda’s desert bomber and a regulation 18″ wheel (hallelujah!) finally made its way to the back of the machine.  All told, the ’88 XR600R dropped five pounds suet and gained a major step up in performance.

After 1988, it would only be incremental changes for the might XR600R. In 1991, it would finally get a much-needed upgrade in brake performance with the adoption of a powerful Nissin rear disc brake. The ’91 season would also see a major step up in fork performance with the adoption of Showa’s highly touted 43mm cartridge sliders. Maybe to help pay for the new brake and forks, Honda also deleted the trick stainless headers in use since 1988.

After 1991, it would only be slight tweaks and Bold New Graphics for Honda’s big earth mover. During the nineties, it would soldier on mostly unchanged, but reach cult status through the exploits of GNCC freak of nature Scott Summers. In spite of its desert roots and prodigious girth, Scott was able to pilot the XR600R to an astounding five GNCC titles.

In 2000, the XR600R would finally be retired in favor of a new machine, the XR650R. Even though the XR had reached the end of its lifespan, it did continue to live on in Honda’s lineup in the form of the street-legal XR560L. Nearly identical to the off-road version, the XR650L continues to this day as the spiritual successor to the iconic XR600R.

 

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