GP’s Classic Steel #81: 1986 Honda CR250R

For this week’s Classic Steel we are going to take a look back at the machine that epitomized Honda’s mid-eighties motocross dynasty, the awesome 1986 Honda CR250R.

For this week’s Classic Steel we are going to take a look back at the machine that epitomized Honda’s mid-eighties motocross dynasty, the awesome 1986 Honda CR250R.

Knockout: In 1986, Honda unveiled one of the most dominant motocross machines of all time, the ‘86 CR250R. The red rooster used works technology and unparalleled good looks to crush the competition in the showrooms and on the track.

In America, 1986 marked a pivotal year in the sport of motocross. Prior to ’86, professional motocross in America was truly the Wild West. Exotic works bikes ruled supreme and anything and everything was fair game in the pursuit of champagne and glory. Then ’86 came along, and the party was over. No longer could the manufacturers trot out $100K+ one-off works specials. Instead, the manufacturers were forced to race lightly modified production machines.

The new “production rule” was marketed as a method of evening the playing field for the hard working and cash-strapped privateers. While this sounded good in a press release, the truth about this new rule was that it was aimed squarely at one manufacturer-Team Honda.

Masterpiece: In 1986, Honda introduced an all new 249cc mill for their CR250R. The HPP (Honda Power Port) motor started pulling from the first crack of the throttle and never stopped cranking out the ponies. It offered the widest powerband ever seen on a production 250 and would be the dominant motor in motocross for more than half a decade.

In the early eighties, Honda was the very definition of a motocross powerhouse. With the might of a hugely successful manufacturing empire behind it, they could outspend the other “Big Four” race teams by a factor of ten. Their uber-exotic race bikes were rolling examples of motocross art, and a clear advantage over the competition. In this climate of haves and have-nots, Yamaha petitioned the AMA to make a change and the result was the production rule. With the advent of this new regulation, it was expected by many that the ’86 season would bring with it a new era of parody in the sport, but a funny thing happened on the way to a level playing field – the 1986 Honda CR250R.

In 1986, Honda scored the coup of the century by stealing 1984 National Motocross champion Ricky Johnson away from Team Yamaha. As soon as RJ got on the red machines, he went from one of the fast guys, to THE fast guy.

At first glance, the ’86 CR250R looked to be little more than an ’85 model with bold new graphics. The bodywork was unchanged from the year before and aside from a set of gold rims, it was nearly indistinguishable from the mediocre ’85 CR. In 1985, the CR250R had offered a pleasant (read slow) spread of power and a passible (read crappy) suspension package. Its best trait had been its sharp handling and sweet looks. For ’86, Honda kept the parts that worked (handling and styling) and ditched the ones that didn’t (motor and suspension).

Mouse trap: In 1986 Honda unveiled their version of the variable exhaust port “power valve”. Dubbed the Honda Power Port (HPP), the system used a centrifugal ball governor (the works version had used an electrically controlled servo) to open and close a set of guillotine valves mounted over the exhaust port. At low rpm, the valves were closed, lowering exhaust port height and boosting low-end torque. At 6500 rpm, the governor engaged, and slid the two valves back, allowing better exhaust flow for more top end power.

In 1984, Honda had unveiled their first production version of a two-stroke “power valve” to the motocross world. The ATAC (Automatic Torque Amplification Chamber) system used a small sub-chamber built into the cylinder to increase exhaust pipe volume at low rpm’s and in theory, widen the powerband. This early attempt at an exhaust valve yielded mediocre results (many people blocked them off completely and ran the bike without it) and was far less effective than the advanced electrically operated exhaust valves found on Honda’s RC Factory race bikes. For ’86, (just in time for the production rule) Honda would finally bring this works technology to the workingman with their new Honda Power Port (HPP) mill.

Atlas booster: The HPP motor in the CR250R was a far and away the best engine in the class in ’86. It made the most power, over the broadest range, and delivered it in an electric fashion that any rider could use. At a peak of 38.4 horsepower, it had a two horsepower advantage over the next most powerful bike in the class.

With the new HPP system, Honda pilfered from their works machines and introduced an all-new exhaust valve design. It lacked the works bike’s electric operation (substituting a simpler centrifugal ball governor) but offered the more advanced variable exhaust port operation that changed port timing to suit engine rpm. The Honda Power Port was similar in theory to Yamaha’s YPVS (Yamaha Power Valve System), but different in operation. Where the Yamaha used a rotating drum to close off a portion of the exhaust port, the Honda system used a set of sliding guillotine valves that matched the contour of the exhaust port. At low rpm’s, the valves would be closed, effectively lowering the exhaust port height for improving low-end power. As the rpm’s increased, the governor would engage and slide the two guillotine valves out of the way for better top-end flow. The new Honda system offered very precise control and excellent sealing, but was far more complicated to maintain than the simpler Yamaha system.

Große Vergaser: To get more power for ’86, Honda went big on the CR250R.  A switch to the 38mm flat-slide Keihin (the ’85 used a 36mm) from the CR500R yielded major gains.

In addition to the new power valve system, Honda made several other changes to their previously lackluster 250 mill. An all-new cylinder was spec’d to accommodate the HPP system, featuring revised porting and a works-like Nikasil liner (better heat dispensation and tighter tolerances). In addition to the new cylinder, a new reed valve, pipe and revised ignition were added to squeeze more power out of every cc. Complementing the new more free flowing cylinder was a larger 38mm (the ’85 used a 36mm) Keihin flat-slide carburetor and a higher compression ratio (10:1).

Deep Field: Certainly, much of the credit for Honda’s amazing ’86 season rests not with the bike (excellent though it was), but with their amazing stable of riders. Rick Johnson, David Bailey (pictured) and Johnny O’Mara were all National Motocross title winners (with O’Show and Bailey owning Supercross titles as well) coming into the ’86 season. At many events RJ, Bailey and O’Mara swept the podium, ending up 1-2-3 in the final standings.

On the track, the new 66.4mm x 72mm 249cc mill was a huge improvement over the old ATAC equipped mill. Where the ’85 had produced a strong low-end surge and little else, the new power plant snapped to attention off idle and never stopped pulling.  Power was electric in nature, with no sudden hit or explosion, just an endless flow of torque. It was the only 250 in ’86 that offered power in all three phases of the power curve. It lacked the hard hit of the YZ and KX, but offered far more flexibility and a much wider spread of ponies.  On the CR, if you wanted more power, you just dialed it on and the CR did the rest. No drama, no wasted energy, just hooked-up acceleration. Fast, easy-to-ride and brutally effective, this was the ultimate 250cc racing motor in 1986 (and would continue to be the motor to beat until its replacement arrived in 1992).

After the blazing-fast (but grenade-prone) ’84 CR250R, Honda detuned their deuce-and-a-half in an attempt to keep it in one piece. For ’85, the CR was much more reliable, but dog slow. With the new HPP motor, Honda finally had the winning combination of horsepower and reliability that would be their trademark into the new millennium.

While the new motor was certainly big news in ’86, perhaps the biggest improvement made to the CR250R was in the suspension department.  In the seventies and eighties, suspension technology was still in its infancy in many ways. By 1980, most manufacturers had settled on a foot of travel as the optimal amount, but actual performance left a lot to be desired. As suspension technology progressed throughout the eighties, advances like external damping adjustment were added to allow better tuning (although, adjustment was very limited and of dubious effectiveness) and beefy 43mm legs replaced the flexy units found on the first long-travel designs. These mid-eighties forks were sturdier and more tunable than ever before, but not necessarily any better in performance. In 1986, all that would change with the introduction of the next big step in front suspension performance – the cartridge damping system.

With the advent of the production rule, Honda was not longer able to race their exotic mega-bucks specials. These new “works-production” race bikes had to use the stock bike as a base and only allowed minimal changes be made. Even with this handicap, Honda still had the best bikes on the track in ’86 by a substantial margin.

Prior to ’86, all the forks found on production motocross machines employed what is referred to as a “damper-rod” design. The damper-rod damping system controls movement by using a simple set of orifices drilled into a rod, which restrict the flow of hydraulic fluid as the fork compresses and rebounds. This type of damping is simple and straightforward. The faster the wheel moves vertically, the more oil is shoved through the holes. 

The problem with this type of damping system is two-fold. With a fixed orifice damper-rod fork, the damping can be both too progressive and too harsh. In low-speed situations, the fork tends to flow too much oil, allowing the fork to dive excessively. Then on sharp impacts and square edge bumps the damper-rod design suffers from “hydraulic-lock”, as it can’t flow fluid fast enough to keep up with the action of the suspension. Because the same holes are used for all phases of the damping, enlarging them to cope with high-speed (piston speed, not the speed of the bike) impacts only made the low-speed problem worse. Likewise, making them smaller to increase the low-speed performance would cause a nasty spike in the damping.  It was both too soft and too hard at the same time: the worst of both worlds. 

In 1986, Honda brought true works-bike technology to the consumer with their new Showa cartridge fork. Used on Factory bikes since the mid seventies, the cartridge design offered much finer damping control and a much larger range of adjustment than the damper-rod design it replaced.

The advantage of the cartridge fork is that instead of using a simple set of fixed diameter holes to control damping, it uses a bending-shim-type construction.In this design there is a damping piston with a series of shims (similar to little wave washers) used for damping. The shims are stacked up against the face of the piston and when the oil flows through, it forces the shims to deflect away from the piston face.

The third member of Honda’s ’86 super team was ’83 125 National and ’84 Supercross champion, Johnny “The O’Show” O’Mara. Unfortunately, a knee injury suffered before the first round would hamper Johnny’s results all season (and linger well into ’87). After an solid 3rd overall in the Supercross and 250 National series (and a 4th in the 500 series), The O’Show would be let go at the end of the season in a cost cutting move and sign with Suzuki for the ’87 season.

This design allows much better damping control at low piston velocities (preventing fork dive), while also doing a much better job at handling high speed hits, by flowing more fluid without suffering hydraulic lock (smoothing out damping spikes). In addition offering finer damping control, the cartridge design also did a much better job of separating the air from the fluid, preventing frothing and offering more consistent performance. With better control at low speed and better flow at high speed, both ends of the suspension spectrum are improved.

Works: In 1986, after more than a decade of fork futility, Honda finally had the best forks in motocross. The 43mm Showa cartridge units were plush, well damped and so much better than anything else available at the time that it was almost laughable.

Another benefit of the cartridge design was the much wider range of tuning it offered. Unlike a damper-rod design, where every setting was a compromise, a cartridge fork could be “valved” separately for different parts of the damping curve. If the fork felt good on low-speed, but too hard on high speed, you could revalve the damping to affect only that portion of the curve. This allowed a level of fine-tuning previously only seen on works bikes (which had been using cartridge designs since 1976).

Jigsaw: To say Honda’s new HPP system was a bit intimidating to a generation of riders raised on claw-hammer simple machines would be a bit of an understatement. Even worse, Honda recommended that the entire assembly be taken apart for cleaning after every two hours of use.

With the introduction of the cartridge damping system on the CR250R, there was really only one suspension game in town in ‘86. The 43mm Showa’s were light-years ahead of the damper-rod competition and nearly an unfair advantage. Spring rates and damping was spot on, with a level of plushness never before combined with such excellent big-bump absorption. They were equally at home on stutter bumps and double jumps, with none of the harshness found on the green, white and yellow machines. This was literally a works bike fork, bolted to a production machine. For perhaps the first time in recorded history, a Honda owned the best forks in motocross.

Not everything was perfect on the ’86 CR250R. A new linkage was supposed to offer smoother action, but it did little to improve performance. Slightly harsh on compression and too light on the rebound, it was still the best of a very mediocre field.

While it was nothing but wine and roses for the front end in ’86, all was not peachy out back. Since its introduction in 1981, Honda’s Pro-Link suspension had played second (and sometimes, third or forth) fiddle to Suzuki’s award winning Full-Floater rear suspension system. Year in and year out, Suzuki claimed the title of best motocross rear end. In 1986, the rest of the class caught a break, with Suzuki’s decision to round-file their original Floater design. The new eccentric-cam linkage turned out to be a huge step back for the RM, leaving the door open for a new champ in the suspension wars. 

In ’86, Honda Team riders David Bailey and Rick Johnson enjoyed several epic duals on their works-production CR’s. In the Supercross and 250 Nationals, the Bad Boy came out on top, but in the 500’s Bailey came out the victor.

With the old champ on the ropes and Kawasaki and Yamaha apparently unable to produce a decent rear shock, Honda took the title of best rear suspension by default. Unlike the front, the victory was more due to the incompetence of the competition, rather than any excellence on Honda’s part. The Pro-Link rear end was passible in operation and marginal in performance. It offered a decent, if slightly harsh ride and could be raced in shock condition. It was too quick on rebound and had a tendency to get very busy if the throttle was chopped in the rough. Even with these peccadillos, however, it was still the best of a flawed field.

In 1986, Honda set the standard for things like grip quality, lever feel and lever durability (Honda’s forged alloy levers would bend instead of snapping off in a crash).

In the chassis department, the ’86 CR was largely the same excellent handling unit it had been the year before. Geometry remained unchanged, but additional material was added to the welds in strategic areas and larger diameter tubing was used in the frame’s backbone. In addition to the larger tubing, the critical swingarm mounting area was beefed up to fight chassis flex and improve handling in the rough.

On the track, the ’86 CR250R was an absolute Supercross scalpel. It carved rings around the other machines and craved the inside line. No turn was too tight and no line too tricky for the red rocket. The excellent ergonomics made weighting the front end a breeze and greatly aided the handling prowess. With its snappy power delivery and excellent front suspension, airtime was a breeze on the CR. Its only handling fault was its epically bad headshake at speed, which was nasty enough to rip the bars from your hands late in a moto. This was pretty much par-for-the-course with eighties Honda’s and an expected tradeoff for its impeccable turning manners.

The ’86 CR’s would be the last ones to use a drum brake in the rear. In ’87, all the full-size machines would get an upgrade to a disc’s front and rear.

In the detailing department, the CR was very good for the time, with excellent build quality and premium materials. Bolt selection and uniformity were a cut above the other brands and items like the seat foam felt better initially and held together longer without breaking down. In ’86, the Honda’s grips were the only ones actually suitable to leave on the bike and the stock steel bars were considerably stronger than even many aftermarket offerings of the time. 

In ’86, the stock chrome-moly steel bars on the CR were far stronger than the butter-soft low-carbon steel units found on the competition.  The stock Honda bars were so tough in fact; that they even outperformed aftermarket units like Renthal in strength tests.

In spite of lacking a rear disc, the Honda’s brakes were the best in the class by a wide margin. They offered excellent power, feel and were nearly maintenance free. Overall reliability was extremely good, but some bikes developed water pump problems and the HPP was a major pain to service (a bit of maintenance Honda recommended be done after every two hours of use).

The gold standard: Probably the most dominant line of motocross machines in history, no bikes have ever waxed the competition as thoroughly as the CR’s did in ‘86. Top to bottom, 80 to 500, they were the class of the field and some of the best machines of the entire decade.

In 1986, Honda unveiled the perfect weapon against the AMA production rule. While the other manufactures were busy trying to derail Honda’s skunk-works department, Big Red was actually building a better motorcycle. With the new “works production” ’86 CR’s, Team Honda enjoyed its most dominant season in history. The new CR250R was rocket-fast, had works bike forks and looked like a million bucks. It was head-and-shoulders above anything else available at the time and at $2598, a screaming deal. In 1986, if you rode anything but a Honda, you were riding for second place. 

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