GP’s Classic Steel #67:1978 AMF/ Harley-Davidson MX-250

For this week’s GP’s Classic Steel, we are going to take a look back at Harley’s last endeavor (at least for now) into the world of motocross, the 1978 AMF/ Harley-Davidson MX-250.

For a brief time in the mid-seventies, Harley-Davidson was actually a motocross power in America. They fielded a Factory race team and built a limited run of production machines to back it up. Limited success on the track and in the showrooms would lead Harley to shut down the program before the end of the decade.

Harley-Davidson, the quintessential American icon- it is as American as hot dogs and apple pie. The bikes from Milwaukee are loved for their distinctive styling and renowned for their unflinchingly American character. They have a look, a sound, and a heritage all their own. In the world of street bike cred, there is Harley, and then there is everything else. Today, that company is an American success story; in the seventies, however, things were very different for the bar and shield.

For the power plant, AMF/ Harley turned to its Italian subsidiary Aermacchi. The 242cc Italian mill pumped out major horsepower number on the dyno, but lacked torque and usability. The powerband was very reminiscent of a big 125, with a screaking top-end and little else.

In the early 1960’s, Harley-Davidson made a move to diversify its product portfolio by purchasing the Italian motorcycle firm Aeronatica-Macchi and forming Aermacchi Harley–Davidson. Harley would use this Italian connection to provide them small and inexpensive two-stroke machines to sell in America. These imported “Harley’s”, were actually little more than cheap Italian runabouts, rebadged for the US market, but it did give the American maker a foothold in the exploding small bike class. In 1969, Harley would be acquired by recreational equipment giant American Machine and Foundry (AMF) and officially become AMF/ Harley-Davidson.

While the motor pumped out impressive peak power numbers, the rest of the motor package was in need of refinement. The Harley’s clutch offered an absurdly difficult pull and grabby engagement. In addition to the cantankerous clutch, the transmission suffered from a notchy engagement and oddly spaced gears.

In the early seventies, AMF/ Harley would make the decision to dip its toes into the waters of the competitive motocross market. At the time, racers had a huge selection of potential mounts vying for their hard earned dollars. Sweden, Germany, Britain, Spain, Czechoslovakia and even upstart Japan all offered motocross machines in 1973, and AMF wanted a piece of the action. Leveraging their Italian division, Harley set out about the task of fielding a competitive motocross race machine for the US market.

In 1976. AMF/ Harley hired Southern California pro “Rocket” Rex Staten to help develop the new machine. In 1977, Rocket Rex would be joined by Marty Tripes, and Rich Eirstadt on the Harley Factory team and actually race the national on the orange machines. Although Rex and Marty were fast at times, they were never able to pull off a National victory on the Italian machines. In the end, the team’s only “major” victory would come at the Florida Winter-AMA round with Don “Killer” Kudalski at the controls.

In 1975, Harley would field its first “production” 250 racer, the MX-250. This first attempt would be very limited in scope, with Harley only producing 65 units and selling them through select dealers. By far the most distinctive feature of the ’75 MX was its odd rear suspension. Harley took the interesting approach of actually bolting on a set of front forks to the rear of the MX-250. Although they worked admirably well, they looked bizarre and branded the bike as some kind of Rube Goldberg experiment. After this initial machine met with tepid success in the press and on the track, Harley decided it would be best to go back to the drawing board and redesign their 250 racer.

Although the Harley MX-250 was essentially a prototype offered for sale to the public, it was admirably well engineered. Items like this airbox were well designed; offering easy side access and excellent water protection.

During Harley’s brief flirtation with motocross, they produced two “production” machines which were made available to the buying public. Neither bike met with overwhelming success in the marketplace. All told, less than 1000 MX-250’s were ever sold.

In 1976, Harley stepped up their game by hiring “Rocket” Rex Staten to be a test rider for the fledgling program. Staten, a very fast pro from southern California at the time, had earned a reputation as one of the hardest riding men in motocross. His name would lend legitimacy to the race program, and his hard charging riding style would help the brand work out the bugs inherent to any new program. With Rocket Rex at the controls and a diverse collection of resources at their command, AMF/Harley-Davidson prepared to take a second stab at the lucrative American motocross market.

One look at the barrel and suspension on Staten’s Factory bike, and you can tell it did not share a whole lot with the bike you would find on a Harley showroom. Staten was not particularly fond of the machines, commenting that their power and handling left a lot to be desired.

For this second attempt at a competitive motocross racer, Harley looked to suppliers from all over the world for its components. Assembled by Aermacchi in Varese, Italy, the bike used electrical and suspension components from Japan, an Italian motor, a German frame, hubs from France laced to rims from Spain, and finally, bodywork from the USA. It may have bore an American name on the tank, but the MX-250 truly was an international machine.

The AMF years remain a black mark in Harley’s illustrious 100+ year history.

AMF/Harley’s new motorcycle offered quite an impressive spec sheet, with parts being sourced from suppliers all over the world. Japan, Italy, Germany, France, Spain and the US all provided components used in the creation of the MX-250.

With the original ’76 MX-250, a great deal of Harley’s problems had been with its underpowered motor. The first bike had used what amounted to a hopped-up Italian street bike motor for power, with predictably poor results. For the new bike, Harley did not want to make the same mistake again, and spec’d out a thoroughly modern (for the time) two-stroke mill. Once again, Harley reached out to Italy and their Aermacchi division for a suitable power plant. The five-port 72 x 59.6mm two-stroke motor Italy provided displaced 242cc’s and offered far more power than the mill it replaced. The motor used a chrome cylinder liner for better heat dispensation and lighter weight (just like Honda’s works bikes), and breathed through a 38mm Italian Dell’orto carb. Finally, a Japanese Dansi electronic ignition handled the spark and made the package go.

For the MX-250, Harley looked to the supplier of the best suspension components of the time-Kayaba. The 36mm KYB’s on the Harley were the same units found on the class leading RM250 and offered a competitive for the time nine inches of travel. Performance was on the soft side, with spring rates unsuitable for its Open class girth.

On the dyno, the new mill pumped out a very solid 32 horsepower. These impressive numbers put it right with the top of 250 power plants of ’78. In terms of outright power, it was just ahead of the new works replica CR250R Elsinore and behind only the blazing fast rotary-valve Can-Am 250. On paper, the Italian mill looked to be a real winner, on the track, however, it was a handful. While peak power was plentiful, the breadth of that power left a lot to be desired. The motor offered the classic “all-or-nothing” two-stroke delivery, common to racing motors in the days before reed valves and variable exhaust ports became ubiquitous. When it was on the pipe, the MX-250 could hang with anything, if you let it fall off the powerband, however, things got ugly.

While the MX-250 was largely conventional in construction, some oddities did still exist. This Rube Goldberg chain guide/tensioner used a large coil spring to take up slack and keep the chain on track. The construction of the rear swingarm was also somewhat crude, with its many separate metal plates welded together like something from a high school metal working class.

For controls, Harley turned to Tommaselli of Italy for the MX-250. These premium levers and controls were some of the best available at the time and featured an excellent feel and durable forged alloy construction.

The ’78 MX-250 ran very much like a big 125, with all its power located high up in the rev band. Low-end torque was completely non-existent, with mid-range thrust being only marginally better. In order to get the most out of the Italian mill, a rider had to keep the Harley pinned at all times and carry a lot of momentum. Not aiding matters, was a grabby and difficult to use clutch, which made fanning difficult and modulating near impossible. With its pippy delivery and cranky clutch, getting the most out of the 250 Harley mill took a great deal of skill and patience.

The stock pipe on the MX-250 did not tuck in particularly well and was a notorious leg roaster.

While the motor was a bit of a mixed bag, the suspension on the MX-250 was actually quite good. Unlike its funky predecessor, the ’78 Harley MX-250’s suspension was perfectly conventional for the time. For componentry, Harley looked to Kayaba of Japan, and spec’d out the same basic units found on the class leading RM250. The 36mm legs offered nine inches of travel and a leading axle design for better steering precision. In the rear, the MX-250 used Kayaba’s top-of-the-line remote-reservoir dual shocks (also shared with the RM’s), which punched out nine inches of travel.

For the rear, Harley once again looked to class leader Suzuki and their RM250. The dual remote reservoir KYB shocks were straight off the Suzuki and offered nine inches of travel. Unfortunately, for MX-250 customer’s, however, the Harley was not set up nearly as well as the RM. Spring rates were far too light for motocross with big hits equating to a solid thud!

On the track, the MX-250 offered an extremely plush ride both front and rear on small chop, but was not fond of big impacts. Large jumps or high-speed whoops made the bike a handful, as it tended to use up all of its travel fairly easily. When Harley set up the MX-250, they spec’d the KYB’s with the same spring rates Suzuki used on its RM125-C, which unfortunately weighed far less than the Harley’s porky 250 pounds. This made the suspension excellent for off-road and trail use, but less than optimal for hard-core motocross. With only nine inches of suspension, the Harley also offered far less travel than bikes like the CR250R, which were approaching a full foot of movement by ‘78. With the Harley, you had the suspension of a trail bike, mated to a motor only a MX pro could make work. Not a great combination.

Say what you will about its performance, but there is no debating that the Harley was a pretty cool bike. Lots of little details like these embossed fenders and its works-like leather straped on tank set the MX-250 apart from your run-of-the-mill Nippon MX’er.

In terms of handling, the MX-250 actually performed pretty well given its absurd weight (25 pounds more than its 250 competition) and overly soft suspension. In the corners, its soft forks let the front dive and take a bite, and it hooked up well as long as you did not let it come on the pipe mid-corner. With its light switch powerband and explosive delivery, care had to be taken not to upset the chassis at an inopportune moment. In the rough, the heavy bike could be quite a handful, as it crashed through its soft suspension and tried to eject its pilot. Headshake, however, was not an issue, as the MX-250’s longish 58-inch wheelbase offered the excellent high-speed stability needed in a bike expected to do dual duty as a desert racer. Even with a suspension upgrade, the MX-250 was too heavy to be called nimble, but it was a serviceable motocross weapon.

Braking power was a bit of good and bad with the MX-250. The Harley’s front brake was considered very good for the time, but the rear was less well liked by testers. The combination of a hard to reach lever, bloated running weight (It was a Hog after all) and marginal braking power made large downhills a dicey proposition on the Italian steed.

In the details department, the Harley-Davidson MX-250 was surprisingly well finished for a boutique racer. Fit and finish was very good with quality welds and hand assembled craftsmanship. Features like the leather strapped tank, rubber dampened cylinder fins, Harley-Davidson logo embossed Preston petty fenders and spring loaded chain guide/tensioner showed the Italian’s attention to the details. Everything from the forged Tommaselli levers to the premium Akront shoulderless rims was top quality and durable. Braking in the front was excellent, but most testers found the rear unit underpowered for the bikes prodigious weight.

After the failure of their motocross program in ’78, AMF/Harley-Davidson would shudder the doors on their off-road program for good and go back to building the Softtails and Electoglides that were the core of their business.

For a brief 12 months, Harley-Davidson was a major player in the American motocross market. The had a factory race team consisting of Rex Staten, Marty Tripes, and Rich Eirstadt and an all-new motocross machine ready to wow an awaiting public. Unfortunately, the bike was overweight, difficult to ride and at $1695, a good $200-$300 more than its Japanese competition. When you added in a dealer network that didn’t know a powerband from a sissy bar, you had a recipe for another American motocross failure. After five years, countless thousands of dollars spent and less than a thousand actual motorcycles sold, AMF/Harley would mothball its motocross program for good. In 1978, Harley would sell off its Italian subsidiary to the Castiglioni brothers, who would rename the operation Cagiva and eight years later win the 1985 125 World Motocross Title. Better late than never I suppose.

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