Harley MXer – 1975 Harley-Davidson SX250

In America, Less than 5k, Off-Road by Tim HuberLeave a Comment

Share Button

In 1969 Yamaha released its wildly popular 250cc DT-1, selling around 50,000 units in its first couple years of production. Other manufacturers took notice of this, including Harley-Davidson. They would toss their hat in the MX-ring the following year in an effort to nab a piece of the lucrative late-’60’s/early-’70’s off-road segment. Harley had recently purchased a large stake in Aermacchi, producing numerous small-displacement machines that were atypical of the iconic Milwaukee-based manufacturer. In ’69, Harley began offering what was essentially a version of the 125cc Aermacchi Rapido with a high-pipe, though it still wasn’t really much of an off-roader. In ’73 Harley released the SX125 MXer, shortly followed by the SX175 in ’74. The next year Harley would bore out the 175’s cylinder by an additional 35%, giving birth to the ’75 SX250, a quarter-liter two-stroke machine that inherited most of its DNA from its older, smaller siblings. Though the SX’s were technically H-D’s, the American moco opted to utilize its factory in Varese, Italy – a former production center of Aermacchi’s – to produce the MX bikes.

The SX175 and 250 obviously didn’t follow Harley’s previous offerings seeing as they were a different genre of bikes. Despite the machine’s existence being a result of wanting to strike back at Yamaha’s DT, the SX managed to retain a little bit of Harley-Davidson’s character in the form of the high handlebars and droplet tank. The H-D 250 MXer was a competent machine too, but despite these factors, Harley had some serious issues trying to sell the damn things. Only 14,000 units were built during the SX250’s half-decade production-run, with less than 500 coming out of the factory in the machine’s final year. Dirt and off-road enthusiasts weren’t really accustomed to buying their brappers from a Harley dealership, (also they had previously established brand loyalty to British or Japanese MXers), and Harley dealers were none too excited or enthused when it came to stocking or pushing the SX’s. These were European import bikes, and the machine’s Italian birthplace made many diehard H-D enthusiasts feel these weren’t “genuine” Harley-Davidsons, seeing the MXers – with some justification – as more of a shameless cash grab.

Because the SX250 was the American moco’s answer to Yammy’s DT, the quarter-liter Harley dirt-goer was also powered by a 243cc air-cooled, single-cylinder, two-stroke engine, though the SX’s boasted oil injection with its piston-ported, chrome-plated cylinder inhaling through a Dell‘Orto PHB32 carb, and its capacitive-discharge ignition providing spark. Gears provided drive to the wet multiplate clutch, and a five-speed transmission and chain to the rear-wheel made up the rest of the machine’s drivetrain. The oil-burning thumper boasted a compression-ratio of 10:1, reportedly making between 19 and 23hp at 7,000rpm, and had a top-speed of just over 70mph. In total, the SX250 weighed in at claimed 275.6 lbs, giving it a power-to-weight ratio of 8.56 lbs/hp.

Wrapped around the quarter-liter two-stroke power-plant was a dual-cradle steel tube frame, dampened up front via a telescopic “Ceriani-style” fork, and in back by a swingarm controlled by a pair of spring/shock units that boasted five adjustable preload settings. Not unlike the components the Rickman Brothers had pioneered in the UK for their high-performing MXers, the SX250 also sported a swingarm that utilized snail cam adjusters which made dialing in the rear-wheel’s alignment significantly easier. The rear-wheel also cleverly used a quick-detach system that allowed for faster tire repairs/swaps. The SX actually had a couple noteworthy features along these same lines, such as an ignition system that was completely independent of the battery, enabling the engine to fire up and run without one. The kickstart lever drove through the primary, which meant the engine could be started while in gear, potentially saving valuable time in competition. The 3.25” x 19” front tire was wrapped around a spoked rim fitted with a drum-brake, while the rear 4” x 18” rear shared the same components.

The sum of all these elements lead to a decently competent machine that boasted solid performance on and off-road. Though their machines were highly modified, Larry Roeseler and Bruce Ogilvie both piloted SX250’s to victory in their respective classes in the 1975 Baja 500. That was Harley-Davidson’s first win in that event, and they have yet to repeat the feat over four decades later. The SX did have its flaws here and there, the frame handled poorly in certain situations, it was 25lbs heavier than the DT, reliability was sometimes an issue, but the SX nonetheless has more than enough positive qualities to outweigh its small number of shortcomings. These machines are undeniably an interesting part of a chapter in America’s favorite motorcycle manufacturer’s history. Parts are still widely available. This particular example underwent a complete engine rebuild less than 500 miles ago. In total 5,147 miles are on the example’s odo. It’s reportedly in solid running condition, and ready to go take on some hare scrambles.

You can find this 1975 Harley- Davidson SX 250 for sale here on Craigslist in Brooklyn, New York with a price of $4,000.

Share Button