Playing in the Dirt: 1974-1978 Harley-Davidson SX250

The Harley-Davidson SX250 was created to counter the Yamaha DT-1 during the offroad bike craze in the 1960s.

Harley-Davidson SX250

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When the lightweight offroad bike craze hit the U.S. in the late 1960s, Harley-Davidson was perfectly positioned to compete. But H-D’s dirt diggers didn’t hail from Milwaukee — or anywhere else in the U.S.

In 1960, Harley bought a 50 percent stake in the cash-strapped Italian motorcycle company Aermacchi. Parent Aeronautica Macchi had spun off its motorcycle division to focus on its core business: aircraft. Based in their old seaplane factory on Lake Varese north of Milan, Aermacchi produced a sturdy but rather staid overhead valve 4-stroke single that became the H-D Sprint in the U.S.

Offroad bikes were quickly growing in popularity in the 1960s U.S. market, so when Yamaha turned the dirt bike world upside down in 1968 with the 250cc DT-1 (selling as many as 50,000 a year by the early 1970s) other makers were bound to follow. For 1969, Harley offered a high-pipe version of the Aermacchi-built 125cc Rapido, but it was no offroad machine. Aermacchi Harley-Davidson’s first real counter-offering to the DT-1 came five years later with the 1973 SX125, followed quickly by the 1974 SX175 and finally the SX250. The SX175 and SX250 were essentially identical apart from the 250’s larger cylinder bore.

Like the DT, the SX250 was powered by an air-cooled, 2-stroke, single-cylinder engine with oil injection. A 32mm Dell‘Orto PHB32 carburetor fed the piston-ported, chrome-plated cylinder, while a capacitive-discharge ignition provided sparks. Drive to the wet multiplate clutch was by gears, and a 5-speed transmission and chain to the rear wheel completed the drivetrain. The engine fitted into a dual-cradle steel tube frame with a Ceriani-style front fork and swingarm rear controlled by a pair of spring/shock units with five adjustable preload settings. Tires were 3.25 by 19 inches front and 4 by 18 inches rear.

Though conventional in most ways, the SX250 incorporated a number of useful features. The ignition system was independent of the battery, so the engine could be started and run without one. The swingarm used snail cam adjusters (a scheme pioneered by Rickman Motorcycles in England), making it easier to accurately set rear wheel alignment in the field. Equally practical was the quick-detachable rear wheel for fast tire repairs. Oil for the pressure-fed lubrication system was carried in the top frame tube; and the kickstart lever drove through the primary, meaning the engine could be started in gear — a real boon in the dirt.

The result was a machine that could be made competitive in offroad events with the right upgrades. Enduro legends Larry Roeseler and Bruce Ogilvie used a highly modified SX250 to win the motorcycle class in the 1975 Baja 500, recording Harley-Davidson’s only win ever in that event.

But there was a problem. Notoriously conservative, H-D dealers were loath to stock and sell the European imports, which — with some justification — were not considered “real” Harleys. And as the Motor Company discovered, neither were dirt bike customers predisposed to buying from a Harley-Davidson dealership. These were also the AMF years for H-D when the brand was in bad shape overall. Sales of the SX250 were underwhelming, with estimates claiming just 14,000 units built over the five-year production run and fewer than 500 built in the final year, 1978. That rarity does, of course, enhance their collectability, but it also makes them harder to restore.

So what did owners and riders say about the SX250? At 275 pounds, the SX was at least 25 pounds porkier than a DT-1, never an asset when the pavement ends. And while the engine made good power, more than a few thought it was bolted into an ill-handling frame. Reliability was also said to be an issue, but it’s not reported which of the SX250’s components were responsible — though chrome-plated cylinder bores as used were notoriously fragile in other applications.

Overall, however, the reports point to an under-appreciated and perfectly usable machine that came with what were then typical issues with small Italian motorcycles such as electrical problems and poor plating. Complete bikes are still relatively cheap (though often pretty crusty) and there seem to be abundant supplies of used parts online.

Once derided by the Bar and Shield faithful, Harley’s Italian-built bikes are slowly being appreciated for their role in Harley-Davidson history and interest in them has been steadily rising.  MC

Contenders: 250cc offroad rivals to Harley’s SX250

1974-1976 Honda MT250 Elsinore
Claimed power:
16.9hp @ 6,500rpm/76mph
248cc air-cooled 2-stroke single
5-speed, chain final drive
260lb (dry)/45mpg
Price then/now:
$870 (1974)/$400-$1,500

Named for the famous Lake Elsinore, California, race, the MT250 was both more — and less — than a street-legal version of the 1973 CR250M Elsinore from which it was derived. Gone were the chrome moly chassis, alloy wheel rims and magnesium castings; added were lights, a battery and turn signals. Those omissions and additions brought dry weight up from a very light 214 pounds to 260 pounds. However, both machines shared the same basic powertrain, a 250cc piston-port 2-stroke single.

To make it a little more civilized, the MT got more relaxed porting in the iron-sleeved cylinder, heavier flywheels and a 28mm Keihin carburetor. A flywheel magneto/alternator provided ignition and powered the 6-volt electrical system. Suspension and wheel components were borrowed from the XL250, including the five-way preload adjustable rear shocks and 21-inch front wheel.

True to its lineage, the MT250’s performance was competent but modest. Cycle World liked the engine’s “grunt” and found the power “ample,” noting that “engines don’t break as often in mild tune.” The rear suspension was considered inadequate on rough ground, but Cycle said their main beef was the MT250’s scant range of 90-odd miles. In typical Honda fashion, attention to detail was impeccable. “Honda almost never fails to improve the breed with a new model,” said Cycle. “This new machine is no exception.”

1976-1978 Hodaka 250SL
Claimed power:
18hp (est.)
246cc air-cooled 2-stroke single
5-speed, chain final drive
285lb (dry)/45-55mpg (est.)
Price then/now:
$1,095 (1978)/$900-$2,900

Credited with instigating the U.S. dirt bike craze with its 1964 90cc Ace, Hodaka’s biggest dirt bike, the 250SL came to market in 1976. Designed and distributed by Pacific Basin Trading Co. (Pabatco) in Athena, Oregon, Hodaka frames were deceptively simple in structure, using straight tubes wherever possible and triangulated for strength. Hodaka fitted their own engines and completed the assembly in Japan.

The 250SL engine used an iron-lined alloy cylinder for durability, with a 30mm Mikuni carburetor, Kokusan CD ignition, oil injection and “primary” kickstarter for quick restarting in gear. A 21-inch front wheel with 7-1/4-inch travel front suspension, 9-1/2-inch ground clearance, quick-detach rear wheel, Preston Petty fenders and spark arrestor muffler indicated serious offroad intentions — though the 250SL was also street legal with a full lighting set and turn signals. A more focused trail model, the 250ED, which ran sans lights, was also marketed.

While early Hodakas were praised for their lightness, the 250SL weighed 285 pounds dry — heavy for its class — and though Hodaka didn’t list output (estimated at 18 horsepower), the SL was also considered underpowered. That said, Hodakas are enduringly popular, and there’s good parts availability from

Hodaka motorcycle production ceased in 1978 when owners Shell Oil closed Pabatco.