Honda XR 600R

How many motorcycles can you name that won Baja 1000 races spanning a 12-year period? Not to mention nine off-road championships and dozens of other major off-road events. Only one motorcycle makes the cut: Honda's mighty XR600R. Honda's off-road four-strokes have been immensely successful in terms of both sales and race wins for decades, and the most successful of them all is the legendary XR600R.

First introduced in 1985, the XR600R could claim the XR500R as its predecessor. That bike, first introduced in 1979, also proved to be a favorite of dirt riders everywhere and amassed racing victories all over the world and in a staggering variety of conditions.

The XR600R introduced a number of key features, not the least of which centered on its engine, a power plant that produced lots of grunty torque as well as class-leading top-end power, all spread over an easy-to-ride, seemingly limitless range. It retained the 500's SOHC four-valve RFVC (Radial Four Valve Combustion Chamber) head for maximum valve area. The XR was fed by twin 28mm Keihin carbs (the same as the 500's except for revised jetting). Spent gasses exited through a new, longer, twin headpipe system and redesigned muffler/spark arrestor.

Transforming the dry-sump motor from a 500 to a 600 required surprisingly few changes. Honda's engineers bored the crankcases to accommodate a 3mm-larger bore, while a new crank yielded 5mm more stroke for dimensions of 97.0 x 80mm and an actual displacement of 591cc. While the 600 obviously didn't need as much compression to gain extra torque (permitting it to run on lower-octane fuel found in out-of-the-way places throughout Baja), the new bike's larger, redesigned valves opened in tapered inlet ports to add mid-range punch.

Like Honda's Baja 1000 race-winning XR500s, the 600 featured recalibrated, longer-travel suspension; a new frame with a stout square-section downtube and aluminum swingarm; and an easy-access, no-tools-required airbox cover. The 160-watt generating system was also a direct result of Baja influence. An innovative electronic enduro meter widened the XR600R's appeal, as it provided accurate tracking of distance, speed and time. Trail riders as well as enduro racers found it useful and, if nothing else, very cool.

The remarkable XR600R made headlines throughout its long model life. It won its first Baja 1000 in 1986 by 45 minutes, thanks to riders Chuck Miller and Bruce Ogilvie (both current and longtime Honda employees). In all, the 600 would win the Baja 1000 four times, the Baja 500 three times, the Nevada Rally once, Barstow-to-Vegas once and more desert races than you can count. It was also amazingly versatile: Scott Summers built his reputation by winning nine AMA National championships contested in the woods (four in Hare Scrambles and five in Grand National Cross Country) on XR600s. Summers also won three gold medals in the International Six Days Enduro-the Olympics of motorcycling-racing against the best enduro racers from every nation on their ground.

Through the years, the XR600R was campaigned in motocross and dirt- track races as well, yet throughout its design evolution it never moved far from its original concept. A single 40mm carb replaced the twin mixers, stainless steel headpipes increased durability, an automatic decompression system made starting the bike easy, 43mm CR-style cartridge fork and revalved shock improved suspension response, while an optional Power-Up Kit increased power by 25 percent through a larger piston and a few other changes. The XR600R also received a rear disc brake to complement the front disc it used from the start.

Most significant, the XR600R provided a springboard for the incredible XR650R introduced in 2000. Like the XR500R before it, the XR600R laid the foundation for an evolutionary leap forward, and inspired innovations in the XR650R, such as an aluminum chassis and liquid-cooled engine. In only its first year, the XR650R posted overall wins in the Baja 1000, Baja 500 and the grueling Nevada 2000.

The XR650R is an amazing machine, but no matter how many records the new XR650R breaks, the XR600R's incredible 15-year off-road reign will never be forgotten.

Dirt Rider review 1995

What we have here is the first '95 racing thumper to be released by any manufacturer. Sure, it's unchanged. We all would like to see the Six-Honey lose 20 or 30 pounds, and many would like to have the top-end off of the dual-sport XR650L with liberal use of Teflon and ceramics, but then the XR600R would have a price tag as shocking as a Husaberg 600 or ATK 604E (thanks to Clinton and the Congress, the XR's retail price jumped $300 for '95).
That sort of experimentation and development might hinder XR ace Scott Summers in his quest for more off-road championships. Scott and the XR600R have won six National Cross-Country and hare scrambles so far, and they are in the hunt for two more titles this year. Summers and Honda are also in line for a slot on the home-court U.S. Trophy team for Tulsa's ISDE—and the wins just keep on coming.

Before Summers came along, XR600Rs were touted as mere trail bikes, suitable for cruising for tacos down in Baja or clearing trails back East. Not anymore. Right out of the box, the Honda XR600R is a threat for the overall win at any hare scrambles, cross-country or grand prix.

HOT OFF THE PRESSES

This year's XR600R got only cosmetic changes, so they could be rolling off of the production line before Honda's annual dealer convention, where, no doubt, dealers would give Summers another standing ovation. Not even Jeremy McGrath gets Standing Os at these deals. Summers has made the XR600R red-hot to dealers, so Honda made the XR more red this year.

Instead of orange-red, XR seats and graphics are more blood-red for '95. The numberplate backings are a deeper blue, like the National Supercross Champion sports. Wheel hubs are silver instead of black, to match the air-cooled motor. Last year the XR got a larger, stiffer front axle, and cartridges for the fork before that. Brakes haven't changed, because they are the best—and right off of the CR250R. Rubber, jetting and spring rates are all the same as in '94. That means your local Honda dealer has parts in stock for the '95 right now, if you break something in a get-acquainted crash.

SO, WHAT'S IT LIKE?

Engine:

Honda's Open-class thumper is the lone air-cooled holdout, so it will never boil over. You can make it ping in deep sand or mud, but only the most ham-fisted could break one. If you let the oil turn to mung, you could possibly break third gear or fry a stator, but it would never boil over. The XR starts easily and emits the lowest vibe level of its class, due to a counterbalancer. Ratios are well-spaced in the five-speed gearbox.

Carburetion is crisp, and the XR has a cool altitude compensator system, so you can adjust the mountain mixture without digging for jets and getting gas on your hands. With the airbox inlet snorkel and exhaust diffuser plate removed, the XR600R has enough torque off of idle to wheelie over anything in your path.

Stock, the power is concentrated in the midrange, as the pipe and paper filter choke off some of the top-end overrun (see hop-up sidebar). There is so much power on tap and such throttle response that you hardly ever have to slip the clutch. Steep, technical uphills require plate abuse, more to prevent wheelies than from a lack of gravity-conquering grunt. That's good, because the XR has a fairly heavy clutch pull and levers designed for meaty hands.

Chassis:

Oil rides in the single square downtube, and two round tubes cradle the motor. Engine guards are tubular aluminum, as coal-shovel-style aluminum plates cut heat-dissipating airflow over the lower end. Footpeg lugs are stout, although Summers welds beef-up plates to his. The pegs could be wider (front-to-back) for better comfort, but they are well-placed, ergonomically.

The kick-starter rides low and is easy to use, but the subframe isn't removable. Maybe next year? Headers and pipe are well-shielded and tucked, but the XR is pretty wide in the midsection. It's also wide at the footpegs, meaning it tends to drag in deep ruts made by two-strokes. Anyway, the seat is comfortable, and the fenders do a good job of keeping mud off the pilot.

Rake and trail are pretty much middle-of-the-trail, compared to the competition. It has the shortest wheelbase and seat height in its class, too. The XR has a great compromise between stability and cornering. Weight transfer and throttle response contribute to agility in tight turns, but the XR will headshake in sand-washes. It takes an Act of Congress to deflect the XR600R off-line, though. All that weight has its advantages in boulder fields, but it puts the big XR at a disadvantage in sections with a lot of downhill corners. Good brakes and tires can only scrub off so much momentum, and, at 280 pounds, the XR has a lot to scrub.

Suspension:

Damping and spring rates are set up for plushness, but the overall package is well-balanced and will encourage some serious trail speeds. The cartridge fork has adjustable compression, but rebound is fixed . . . and quick. Overall, the fork offers a smooth ride over rocks and square-edged stuff and doesn't bottom enough to deflect off-line in whoops or mongo G-outs.

The piggyback shock is also set for quick rebound, so it doesn't pack in whoops. It will also bottom fairly easily at race speeds, but it doesn't do any big swappers. Plush initial travel provides lots of weight transfer for sharp cornering and good hook-up on hardpack. The XR tends to wallow a bit when slammed into berms, but Summers prefers the stock fork in western conditions for the plush ride and forgiving fork flex. However, he uses inverted White Powers in rocky or muddy conditions, because the stock conventional fork tends to snag the lower legs on the three Rs—ruts, rocks and roots.

Overall, the package allows you to go fast for long periods without getting beat to a pulp. The quick rebound allows you to preload over obstacles that other open-class thumpers slam right into. Most folks won't even notice that the rear travel is only 11 inches, unless you have a lot of downed logs on the trail. The linkage tends to hang up on logs that Euro thumpers skim over with ease. If that's all we can think of to snivel about, the suspension package must work pretty well, eh?

EFFECTIVENESS, STONE STOCK

With excellent snap, predictable handling, low vibe levels, a comfortable cockpit, plush suspension and the best fuel range of its class, the Honda XR600R is the trail bike and fire-road weapon from hell. It starts easy, holds up well to abuse and has excellent brakes. The IRC knobbies hook up well in almost every conceivable condition and last a long time. As a trail bike, the XR600R is very hard to beat. Other bikes may start a little easier (the KLX650 and ATK 604E) or accelerate a little faster (the Husky 610, Husaberg 600 and KLX650), but nothing can approach Honda's XR overall.

BIG RED ONE HOP-UPS TIPS FROM SUMMERS & PALS

• Stock jetting is 152 main, 62 pilot and two turns out on the airscrew. You can get easier starting and better performance by going to a 155 main, 68 pilot and 2.5 turns out on the airscrew. If you modify the intake or exhaust at all, you will definitely want this jetting. Leapers will also want a PC-1 T-Vent system for bog prevention.
• Summers removes the airbox baffle and uses a Twin-Air filter with the stock backfire screen for more flow and top-end power. If you don't use the backfire screen, you lose throttle response off of the bottom, plus you stand a chance of burning the bike to the ground.
• We have had good results with the new White Bros. E.A.R. SuperTrapp silencer, which boosts top-end flow without an excessive loss of midrange snap or increase in noise. The Bros, also have a new Snuff-R-Not SuperTrapp endplate, so you can get more flow in closed-course events without losing USFS legality on normal trail rides.
• There's also power to be gained by grinding excess weld from the stock header pipes at the intake manifold. Pro Circuit makes an oversized header for its four-stroke performance pipe ($268 complete), which produced the most power on the dyno during our XR pipe shootout.
• High-temp sealant should be used to create a more air-tight exhaust system. Summers also has his headpipes Teflon-coated by Swain Tech, to improve flow and heat dissipation for racing. Swain Tech also coats pistons.
• To further reduce engine heat, Summers trims the back of the front fender to provide more airflow (in dry conditions only). He also removes the headlight and runs an XR250R oil cooler, with custom-made oil lines.
• Proper valve adjustment is essential for top performance.
• Braking makes an oversized front disc kit, which includes a new caliper carrier and pads. It makes a noticeable improvement in power.
• With aluminum Honda low-bend bars, careful tire and tube selection and titanium bolts, you could shave ten pounds off of the 600.
• Honda offers its HRC 628cc kit.  Braking makes an oversized disc (left) and front caliper carrier for the XR600R. Scott Summers likes the extra stopping power it gives in more western-style terrain but uses the stock disc for more clearance in rutty races, which includes piston, cylinder, cam, internal gearing and jets.
• Wiseco offers lighter pistons for the XR in sizes up to 0.08" over (the AMA legal limit).
• Thumper Racing offers wider foot-pegs and ISDE diffuser endplates for the XR600R.
• Summers uses a dry-brake for NAS-CAR-like pit stops.