Honda XR 500R


Make Model

Honda XR500R




Four stroke, single cylinder, SOHC, 4 valve


497 cc / 30.3 cu-in
Bore x Stroke 89 x 80 mm

Cooling System

Air cooled
Compression Ratio 8.6:1


Single 34 mm / 1.34 in piston valve Keihin carburetor




Max Power

36 hp / 26.3 kW @ 6500 rpm

Max Torque

41.4 Nm / 4.2 kgf-m / 30 lb-ft  @ 5500 rpm
Clutch Wet plate


5 Speed 
Final Drive Chain
Frame Welded tubular

Front Suspension

37 mm Showa forks
Front Wheel Travel 224 mm / 8.8 in

Rear Suspension

Pro-link Showa damper, adjustment for spring preload and rebound damping
Rear Wheel Travel 198 mm / 7.8 in

Front Brakes

140 mm drum

Rear Brakes

130 mm drum

Front Tyre


Rear Tyre


Height  1215 mm / 47.8 in
Length 2210 mm / 87.0 in
Width    875 mm / 34.4 in

Wheelbase 1400 mm / 55.1 in
Seat Height 880 mm / 34.6 in
Ground Clearance  280 mm / 11.0 in

Dry Weight

123.0 kg / 271.2 lbs

Wet Weight

137 kg / 302.0 lbs

Fuel Capacity

12 Litres / 3.1 US gal

Top Speed

148.5 km/h / 92.2 mph

Road Test

Cycle 1981

In 1981, Honda retired the dual rear shocks and introduced the 81 XR 500   Pro-Link rear suspension on the XR 500. This new design brought with it a host of new frame revisions. The "Ride Red" folks also changed the front wheel dimensions too. The '81 XR came with a more conventional 21" inch front wheel, rather than a 23" front wheel. As for the rear wheel, Honda, for some strange and disturbing reason, fitted a 17" rear wheel, rather than go with the previous models 18" rear wheel. (Go figure.) Apparently Honda felt that was enough design gymnastics because the engine did not receive much in the way of changes.

The '82 XR 500 received cosmetic updates.

The King Of The Trail Gets Pro-Link Suspension And Reed Induction

Honda's marketing philosophy differs from most motorcycle companies that try to fill an established need or want. If the buying public wants motocrossers with 900cc engines or super serious enduro mounts, they try to build models to fit the use. Honda does this to a certain point— Honda also builds models that don't really fit established markets and then goes after buyers.

Honda's XR line is the most obvious example. They are designed to be whatever the buyer, a four-stroke buyer, wants them to be. Stock, they make great trail or play bikes. With a little modification an owner can compete in enduros and do fairly well if he has the right abilities. The XR line of bikes have been highly successful. And Honda claims the XRs outsell PEs, ITs, and KDXs combined.

Honda enjoys the sales and is concerned about keeping them. Even so, most people were surprised when Honda announced a completely new XR line for 1981. We're used to seeing completely new motocrossers every year or two, we're not used to seeing completely new play or enduro bikes so often.

Three completely new XRs are offered; a 200, 250 and the subject of this test, a 500.

At the top of the new list is the frame with Pro-Link rear suspension. It's based on the system used on Honda's motocross bikes but none of the components interchange; frame material is mild steel, not chrome-moly like the track bikes; the swing arm is chrome-moly steel, not aluminum like the MXer; every part is designed after the motocrosser but for the XR.

Frame tubes on the XR still look small by racing standards but seem to do an acceptable job. The front downtube terminates at the front of the engine, using the engine as a stressed part of the frame and eliminating the need for a cradle while allowing a lower engine placement. The backbone tube is short and lots of gusset-ing and triangulation are used around the needle bearing steering head. Mid-section tubing is widely triangulated with more small diameter tubes, the lower parts ending at the rear of the engine. A rear frame loop with brackets makes a convenient mounting place for a tool bag that carries a multi-purpose wrench.

The swing arm is a beefy box-section piece of chrome-moly tubing and has good crossbracing and gusseting. Snail adjusters are standard. Some people like snail adjusters, some don't. Trying to reinstall a rear wheel with normal snail adjusters can be frustrating and slower than a regular set-up. By the time all of the pieces are in the right place on the axle and the axle is lined up with the axle slot . . . Honda has simplified the job by extending the lower part of the swing arm. It saves all the holding and aligning and cussing. You won't have to fool around with a static arm either. The backing plate slides into a peg on the swing arm.

The shock and lower linkage look like the parts used on the motocrossers. They are similar, but different. The shock has a smaller diameter body that's steel, not aluminum. A smaller diameter spring is used as well. The top of the body is threaded to adjust spring preload and the lower end has a rebound damping knob. The knob adjusts to four different positions that vary the rebound strength and speed of the shock. Rocker linkage is used at the bottom of the shock. The top of the rocker is hooked to the lower part of the shock, the middle pivots on the swing arm, the lower part is connected to the frame by a connecting rod. All moving parts are fitted with grease fittings for ease of maintenance.

Front suspension is as new as the rear. Forks are leading axle Showas but the cartridge is absent. Normal damper rods have taken their place. Good. The 37mm stanchion tubes can be adjusted up and down for steering quickness and they have grooves every quarter-inch or so to make adjustment in the field easier. Triple clamps are new also. They are aluminum and have double pinch clamps. The pinch bolts don't use nuts, the bolts thread into the clamps, simplifying adjustment. Air caps are finally standard too. Handlebar clamps aren't rubber mounted but they are rear set and out of the way when dialing-in the forks.

XRs were the first production bikes to have a 23 in. front wheel as standard equipment. Most people didn't like them and they just didn't catch on. The '81 XR has a 21 in. wheel. Most owners will be happier and when it's time to replace the tire, a bigger choice is available. The rear wheel size has also changed. It's a 17 in-cher, popular with off-road and enduro riders.

Brakes are modern, up-to-date parts. A double leading shoe on the front, a single leading shoe on the rear. Rims and hubs are aluminum and have decent sized spokes.

Visually the engine looks the same except for the black finish. Wrong. The XR500 engine is a first; it has an intake mounted reed cage. Right, a reed on a four-stroke Single. Makes sense when you think about it. It eliminates the biggest problem associated with large four-stroke singles—low-end stumble when the throttle is turned on quickly. The reed works just as it does in a two-stroke; it opens when the piston starts down, causing a vacuum, closes with any positive back pressure from the piston. Thus, air flow through the carburetor never reverses and causes a hesitation in fuel flow.

For the most part, the rest of the engine is unchanged. The four valves are the same size, two headpipes are used, bore and stroke the same, double counter rotating engine balancers remove most of the boom, boom characteristics inherent in large four-stroke Singles, and the clutch is the same. Transmission ratios are unchanged but the transmission shafts and some of the gears are hardened harder. Additionally, fifth gear on the main shaft is 1 mm wider.

The automatic compression release is retained but modified. The kick pedal automatically activates it when the pedal is depressed and a hand lever is placed on the left bar. The operator can release the compression to ease bump starting on loose ground or to clean out a flooded engine.

Carburetion is handled by a 34mm Keihin, 1 mm smaller than before. It's still a double cable push-pull job. but the throttle is much better. It's designed like the motocrosser but has two cables.

The new frame and suspension forced Honda to change the airbox and filter. The new one is larger and more effective than the old but still won't win any awards. Servicing requires removal of the right side cover and the side of the airbox, then loosening of a clamp and wingnut. On the plus side, the air inlet is high on the frame under the seat where water can't easily get to it.

One of the best improvements on the '81 XR500 has to be the seat. It's shaped like the seat used on the MXer; narrow and deep at the front. And the front part doesn't end as vertically. The slanted front means the rider won't be constantly pinched between the tank and seat when perched forward. The old style was annoying and uncomfortable for aggressive riders.

The seat-tank relationship is also different. The plastic tank is shorter, the seat longer—at the front. The riding position is much improved as a result. Loading the front wheel for slippery corners is easier and the rider's position on the machine feels right. The bars are the right bend and shape for most, grips are great, dog-leg levers with rear-set ball ends work fine.

The 95 mph speedo has a flexible reset knob, control cables and guides are first class and the gas filler hole is large. Not much has been overlooked on the newest XR.

Starting is normal four-stroke Single; get it on a compression stroke, leave the throttle completely off and kick like hell. Most of the time one or two kicks will do it. About the time you get real proud of how easy you can start it, the damn thing will wear you and two of your buddies out  before it suddenly lights up like nothing was ever wrong. It usually only happens when the engine is hot from being run hard, but it's frustrating when it does. Occasionally when plunking along at a snail's pace the engine will quit dead. One kick will usually bring it back to life when it happens. We never did figure out why it did it but it happened at least twice each time it was ridden.

The reed has smoothed the power output and eliminated coughing and hesitation. The bike accelerates smoothly any time the throttle is turned on, no matter how quickly the throttle is operated. Low and mid-range is stronger than before but approximately one horsepower is lost at the top end, the byproduct of the reed restricting fuel flow at higher revs. Winding the big engine is wrong, nothing much

happens at high rpms. Power is everyplace in the mid and low-range but flattens out if wound. Short shifting is definitely the right approach to riding the bike.

Drag races between the XR500 and an old PE400 proved the XR the slower, by quite a bit. The PE will outdrag and outrun the XR on top end. Actually, the XR was disappointing on top speed. A speedometer reading of 70 could be obtained if the road was long enough. Taller gearing would help take advantage of the mid-range power and keep the engine from reaching the higher revs where less happens.

Overall the handling is 300 percent better than last year's bike. Whoops up to medium size are taken straight and true. Really big ones are handled almost as well until high speeds are tried, then the suspension travel and weight take over and the bike starts bottoming and becoming a handfull to control. It happens progressively though' and the rider has plenty of warning before critical velocity is reached. Fast trails that snake around and have small to medium bumps are where the XR500 excels. Steering precision will humble some motocrossers. And control at speed is good. The suspension components are busy at speed and the ride isn't as smooth or plush as the CR450R's, but it works fine.

Jumps aren't so good. The bike flies straight and doesn't try to turn over in mid-air, nose dive or loop, but landing will confirm the bike's weight. Stiffening the suspension helps but face it, the bike wasn't designed to be launched from MX-type jumps. Best leave such riding to the guy on the CR.

Even severe bottoming from high jumps doesn't give the rider the impression the bike will break, although it probably would if much of it was done. The frame tubes look too small for the job they have to do but triangulation makes the unit stronger than it first appears. A strong solid feel is present on the roughest terrain.

We experimented with the adjustable suspension. The forks worked best set as they come; 6 psi air, stock oil weight and level, and the stanchion tubes as high as they can go in the lowest groove on the tube. The rear suspension also worked well at the standard settings; stock spring preload, number two rebound notch. The rebound adjuster is a minor hassle to set. The plastic knob doesn't protrude far and it can't be adjusted from both sides of the biJce. Adjusting means putting the bike on the side stand, squeezing your hand between the fender extension and shock, (only possible from the right side of the bike), and turning the knob with one finger. It's hard to feel the detents and several attempts are usually required before you're sure where it's set. The book says the knob has marks on it, if so they are impossible to see. Adjustments won't be needed often but it's too bad the knob isn't larger and the detent more positive.

Sliding corners on firebreak roads is one of the things four-stroke Singles usually do best. Something about the power output that gives the rider that little bit extra feeling of control. The older XR500 did a lot of sawing through corners, the new one prefers to track through them. It'll slide if the rider goes into the corner faster and deeper than Randy Goss or the ground is slippery, but forget it otherwise. Horsepower isn't enough to slide the bike and it can only be done with pure speed going in. Once sliding, the bike behaves itself. Nice and smooth but slides are hard to maintain with the stock engine power.

Gas mileage is supposed to be better with four-strokes. A hard rider will use up the 2.4 gal. of gas in about 60 mi. The petcock is equipped with a reserve and we usually had to use it after the 50 mi. mark. Of course the distance could be less if the bike is ridden in mud or deep sand most of the time. It could also be greater if ridden at a more moderate pace.

The XR500 doesn't feel as big and heavy as it actually is. Not in motion that is. Drop it and you'll know just how heavy 310 lb. (full of gas) is. Underway the Pro-Link eliminates the heavy feel. Steering is easy and sure, the 28 ° rake probably helps mask the weight yet doesn't cause handlebar shake at speed. The bike even handles fairly well in a sand wash. It'll go down them at speed or at a slower pace with good rider control. Winding washes are also taken with a minimum of trouble. Trying to make a square turn in sand doesn't work. The bike responds by digging in with the front wheel and trying to throw the rider over the bars.

Brakes on the newest XR are the best an XR has ever had, though they were poor before. The rear is unchanged but the double leading shoe front makes up for the marginal rear. The front requires a hard pull to stop the bike rapidly from speed but doesn't exhibit any grabbiness or locking. It still doesn't stop like a 220 lb. two-stroke despite the added engine braking. Stopping more weight takes its toll.

We couldn't find much that needs changing on the XR. The tires have recessed square holes in each knob, much like Dunlop K190s and work about as well. Rubber compound and tread design match the bike's use.

So what's the bottom line? We rate the XR500 King of the trail bikes and a fairly serious enduro bike if the rider is hefty enough to wrestle 300 lb. through the woods all day. Taking weight off the bike won't be as simple as it was on the old model. The new one already has a plastic tank, plastic seat base, aluminum rear sprocket, plastic gas cap, etc. It's hard to figure out where the '81 gained 11 lb. The single shock system has to be substantially heavier. Even with the increased weight, the bike will win many buyers. Its good looks, four-stroke power and attention to detail give the prospective buyer a complete package that needs little or no modification. SI

Source Cycle World 1981