Retrospective: 1975-1978 Harley-Davidson/Aermacchi SXT-125

1975 H-D/Aermacchi SXT-125
1975 H-D/Aermacchi SXT-125. Owner: Michael Hopkins, Rohnert Park, California. Photos by Virginia Pearlman.

Here is an attractive little trail bike, built by Harley’s former Italian subsidiary, Aermacchi. Oddly, virtually nothing has been written about this model in the American moto-press. Your scribe has looked many places, and could not find a single road test. More than a dozen Harley histories are on my shelves, some of which never even mention the Italian connection, which went from 1960 to 1978. There is reasonable reportage on the four-stroke Sprint models, less on the two-stroke Rapido 125 and Baja 100, so I am making do with what we have.

Harley should be proud of the Italian connection, because it provided the company with four international GP racing victories when Italian road-racer Walter Villa won the 250 class in 1974, ’75 and ’76, doubling up in 1976 by winning the 350 class as well — riding a parallel-twin two-stroke built by Aermacchi with Harley-Davidson writ large on the fairing.

The name Aermacchi comes from combining the two words from the previous company, Aeronautica Macchi, with which Giulio Macchi began producing airplanes in 1912. However, being on the losing side in World War II, the company had to stop making airplanes and instead moved into basic transportation — the motorcycle. Early models used a four-stroke single from 175cc to 350cc with the cylinder lying forward, almost flat.

1975 H-D/Aermacchi SXT-125

In 1960 Harley, aware of the popularity of bikes like Honda’s small OHC twins, looked at its own small bikes, a couple of rather antiquated 165cc two-strokes that had begun with the 125 Model S in 1948. Which was based on a German DKW bike, the designs for which had been given to the U.S. as part of war reparations. Now the Milwaukee suits tapped on the door of another WWII foe and cut a deal for half the company. In 1961 the first 250 models, called Wisconsins, arrived at dealers — shortly after which it was noted that this bike had nothing whatsoever to do with Wisconsin, and the name was quickly changed to Sprint.

In 1965 the first Italian-built two-stroke came into the country, a little 50cc model that the Harley dealers really objected to. Two years later that grew to 65cc, which did not help much, while the last of the DKW-based two-strokes vanished. Then the 125cc Rapido two-stroke came along in 1968, which was anything but rapid.

1969 was an interesting year for Harley, as an outfit called American Machine Foundry bought the motorcycle company. AMF was best known for selling golf carts and bowling equipment, and thought its sporting knowledge would work well with a motorcycle company. It did not. We won’t get into the Harley-Davidson snowmobile.

For 1970 the little Baja 100 two-stroke appeared, an off-road bike that appealed to quite a few riders. And it won its class in the 1971 Baja 1000 race. This was a serious effort by Harley to build a great desert racer and enduro machine, and they got a lot of help from the racers themselves. The engine was a Rapido cylinder sleeved down to 98cc. An automatic gas-oil mix was developed to simplify fueling.

1975 H-D/Aermacchi SXT-125

Obviously AMF thought that this two-stroke connection was good, and bought the entire Aermacchi Company in 1974. Aermacchi could still pursue its European market, with Walter Villa’s racing, while the profits would go to Milwaukee. The following year was the last for the lone remaining four-stroke, a 250 Sprint.

And it was the first for the SXT-125, a well-designed trail bike that was meant to appeal to the rough-and-ready folk who had liked the Baja 100. The engineers at the Aermacchi plant in Varese built a slightly oversquare engine, with a 56mm bore, 50mm stroke, using piston-port induction. The cast aluminum cylinder liner had a chrome-plated bore, which was quite useful considering the rather serious 10.8:1 compression ratio, providing some 13 rear-wheel horsepower at a little over 7,000 rpm. Kickstart only.

An oil container under the gas tank held a little more than three pints; this had no sight window and the rider had to look carefully into the opening up by the steering head to see if more needed to be added. A Mikuni pump pushed the oil into the intake to mix it with the gas flowing through a 27mm Dell’Orto carburetor. Oil metering was controlled by the throttle, with one cable running to the pump, another to the carburetor.

Electrics were simple enough, with a flywheel-alternator charging a 12-volt battery, and easily adjusted points. Turn signals were mandatory. Up on the dash were two round instrument cases, one being the speedometer. The other, which did not hold a tachometer, served to house the ignition key and lights for high beam and ignition.

1975 H-D/Aermacchi SXT-125

Gears took the power from the crankshaft to the wet clutch, then through a five-speed transmission with its own oil supply. The transmission sprocket had 14 teeth, the rear sprocket, 61. A useful primary starter allowed the bike to be kickstarted in gear after pulling in the clutch.

The frame used double downtubes, with a cradle running beneath the engine and serving as a sort of skid plate. A Ceriani fork did a good job up front, with Betor shocks at the back, adjustable for spring preload. Wheels were a 3.00 x 19 at the front, 3.50 x 18 at the back, both with five-inch, full-hub drum brakes. Wet weight was a respectable 240 pounds.

Seat height was almost 30 inches, with a saddle long enough to move about comfortably. No passenger footpegs. Good-looking machine, with an upswept muffler and 2.7-gallon gas tank. But dealers were not pushing them, and sales did not meet expectations. So what did AMF do? Sell the whole shebang in 1978 to an Italian company called Cagiva. And the “Cagiva HD SXT 125” became a bestseller in Europe.

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  1. As I recall, these bikes were lack luster compared to the Japanese bikes, probably why they failed. I think HD should diversify but make competitive machines not just gap fillers. I think they have the Engineering prowess to do it if the Engineers could just get a chance to build them. Of course they’d have to be price reasonable too which is probably where they would fail. Tough business to be in especially with an old clientele.

  2. I’m happy to read something about these good little machines. I bought a 1975 250 HD from another serviceman in Germany and enjoyed it for about two years before returning to the states. The Germans didn’t know what to make of it, but 8t wasmactually a light and fun bike. Thanks for the memories.

  3. Didn’t rocket red station ride a four stroke put out by Harley in 76.if I remember correctly he was teal competitive too

  4. My first Moto-X bike was a Baja 100, I replaced the rings once and remember how tiny the cylinder hole looked when I pulled the barrel off of the engine. I think I traded it for a RM125 Suzuki.

  5. I bought an earlier version of this (TX125) new in 1973. I paid $490 for it. It rode well and felt like a bigger bike. Power was a little down, but still usable. Very similar, with the following differences:
    1. The exhaust pipe was from the Rapido model of a year earlier. (My twin brother had a ’72 Rapido.)
    2. The frame looks identical.
    3. The cylinder was cast iron. This model looks like aluminum.
    4. The tank was different.
    5. 73 was the first year for oil injection. The oil injection system looks like the same as my 125.
    6. The 73 had dual rear sprockets, one for street and one for trail. I never changed from street, as the trail riding I did never required the extreme gearing provided by the trail sprocket. Plus it looked like a hassle to change.

    I gave up on it when I needed a part and went to the Harley dealer and said “I have a 125 and I need…”. His reply on hearing “125” was “We don’t have it.” Jacklegged some Yamaha parts to make it work. Sold it for $475. Got a Suzuki 185.

    Never been back to a Harley dealer.

    Just as aside, the final years of the Sprint were 350cc.

  6. I have two of these tiny bikes….a 1974 x90, and a 1974 z90. Both are 4 speeds and 2 stroke. The z90 being street legal and titled gets lots of attention at local bike events.

  7. My senior year of high school I purchased this bike in a 175cc configuration as an upgrade from my first bike, a Honda CT50. This was in Germany as my Dad was stationed there in the Army. I don’t know if there was a US 175 version. It was quite fun and as someone else mentioned the Germans didn’t know what to make of this “motocross” looking bike on the street. Interestingly, the tank and fenders were steel. It was so much fun zipping around Europe and I still love the “ring a ding ding” of a two stroke.

  8. In the late 70’s I bought a used SX125 from a relative who couldn’t keep it running. He had bought it from the original owner who also had trouble with it. I couldn’t keep it running so I took it to Suffolk Harley Davidon and it sat there for over a month. They never touched it. They never gave me an explanation why. I brought it home and eventually sold it for $35.00.

  9. A friend had a 90cc Harley around ’73. That piece of crap spent more time in the shop than it did at his house. On a separate note, i bought a year old AMF, FLH Classic in 1981 to travel on.
    I wrenched on that pos for three months, then traded it in on a new Goldwing. Took a bath on it. If you don’t want to go more than 50 miles from home, the Harley was fine. On a 1200 mile trip, i had to have the chain and sprockets replaced and the frame welded where it cracked, along with 30 – 60 minutes of tightening nuts and bolts that had vibrated loose every day and a quart of 70 weight every couple days. This was on a year old bike with about 5000 miles on it .

  10. I owned a 75 175 in orange bought new. It was heavy, kinda slow but I had a blast on it in my teens riding trails and a makeshift MX track. Said right on it, made in Italy too. Most HD dealers just laughed at you if you needed parts. What a bunch of dicks they were.

      • Yep. Sure are. I buy my parts online and save money and work on my bikes myself. I NEVER go to the stealer ship. Rode with my friend to the local dealer not long ago and you should have seen the pretenders buying the Chinese made shirts and other over priced crap. I had a good laugh.

        • Hello Bryan
          Where on line is best place to buy parts for these 1970 s 125 cc Amerachi’s ? Thanks Peter

  11. Went to the (Ventura,CA) dealer in early 1969 and test road a 250cc Harley Aermacchi. Almost ready to buy when the salesperson said a 350cc was about to come out. I said I would wait and to call me. He said I should call him, right, pshaaa! The next weekend I went to the BSA dealer (Port Hueneme, CA) and was ready to buy a 441 Victor, after a test ride. I discovered that they felt anyone that knew m/c didn’t need to test ride. Right, OK, ha. The next weekend, checking behind me closely, my wife and I eased into a Suzuki dealer and test road a 350cc. Almost bought it when the saleslady (that’s right) said, wait, take the 500 cc Buffalo for a test. We did, but bought the 350cc scorcher. Never looked back . I raced Mustangs, Dodge 383s, etc. The Suzuki was a winner. Live and learn.

  12. This was the 1st motorcycle I owned as a new rider I was completely unprepared for the problems this bike would give me. It was A 175CC single cylinder with an oil injector A very handsome bike in great condition hardly used. I felt lucky to find this gem In fact that seem too good to be true and and reality at was as I was riding at home I couldn’t have foreseen that ride would be the last time I rode it. The oil injector never worked right and the bike smoked horribly eventually the electrics burn themselves out and I spent more money trying to fix it and get it working then it was worth. I eventually sold it for next to nothing to someone much more resourceful both mechanically and financially who had an interest in the bike for its unique place in motorcycling history.

  13. I had the street-only version of this, a 1976 250 SS. Biggest POS ever built. Bought brand-new. The frame flexed badly on straight, smooth roads. I thought it was the wheels & had them trued twice, which didn’t help. Then had two major breakdowns in 1200 miles from new (yes, twelve hundred, not twelve thousand). I then switched to a Suzuki GS400 and never looked back.

    Now I’ll never even park next to a Harley, let alone buy another one.

  14. I have owned a 90cc Harley Aermacchi 2 stroke trail bike for 40 years. Unfortunately it was burnt on 19/12/2019 in the devasting bushfires here in New South Wales Australia. A great loss of history of this make. I remember the tank was blue. All the alloy melted in the fire along with 105 of my other motorcycles I had collected over 53 years. All they are good for now is motorcycle garden art.

  15. I have a Harley Chronicle published in 1997 that mentions the 90, the 100, 125, 175, 250, 350, all either two stroke or 4- stroke and also the 750 flat tracker which was a twin cylinder.

  16. 20 plus years ago i met a man in a bar he said he had a 1975 250 cc harley sprint like new with 600 miles on eng well the next day i met him when i saw it it was like the bike just came off the show room floor i said how much he said 700.00 i of course paid the man and took it home oh yes it started after we charged the battery. I took it home cleaned a few things and it had the up sweeping moto cross style exhaust about a week later i got a call from the guy i bought it from that he found the chrome street exhaust to come pick it up well i looked closer and the head had two springs holding the exhaust pipe into the head when i got the street pipe home i quickly changed it from a moto cross or dirt bike style to a very nice street bike. I still have this bike and love riding it around besides the two head springs there is two bolts holding the up sweep exhaust and one bolt holding the chrome street exhust i buy sprint extra parts just incase i need them who knows this bike is lighting fast either way street version or dirt bike style. I have had many offers all turned down. Some things aren’t for sale jim k

  17. Owned a 71 125 Rapido. ALL of my Japanese bike riding pals laughed at it. I had to mix oil, they had auto injection; I had a 4 speed, they had five; they had turn indicators, I had none; they had a neutral light, I didn’t. The lights never worked anyway on mine. And to top it off all of their 90’s and 100’s were faster than my 125. The two years I had it, it spent a LOT of time in the shop worked on by mechanics that didn’t have a clue about Italian two strokes. Sold it and got a Kawasaki and have NEVER considered another anything with HD on it.

  18. I have mostly had Harleys my entire life. Started with M50. My older brother had it. I remember they had problems with fouling plugs. I never did. Then I hadwhat I thought was a 69 125 but pictures show it to be a 68. Run it wide open down the highway about 65 mph. It would vapor lock in the summer. Then a 76 SX250 man that thing was fast! Loved all of them and did not have reliability problems. I was a kid and pounded them in the dirt. They took it!

  19. I’m currently restoring this exact bike. I unfortunately broke a piston ring upon removal and am having a helluva time finding a replacement. The frame has totally been stripped, primed and repainted gloss black with a high heat enamel paint. The bike only has 600 original miles! Can’t wait to start bolting on all the parts I’ve stripped and repainted in a flat black. If anyone has any advice on what to do about the piston rings feel free to reach out.

  20. I’m 63 years old and I was fortunate to live & ride during some of the best years of motorcycling. I do have to say that the Harley davidson 125 was an Italian piece of crap. Those individuals that bought a new one could not give it away. One of my friends owned one. Me being a motorcycle mechanic for 45 years learned me one thing & that is to spot junk pretty quick.

  21. There was several around way back in the early 70s and today I think Harley would do very well building a high fender dual sport trailstreet machine starting at a 175 all the way up to a 650 c.f. like the KLR 650 But made by Harley it would diversify them and help them make a come back maybe even try 4 wheelers and side by sides but I really do think a dual sport Harley would sell well! I think Harley made a dual sport bike exclusively for the military years ago

  22. Evil Kenevial use to own one of these Red Rock Harley Davidson dealership in Las Vegas has an awesome memorabilia of Evil Kenevial collection got to go out there and check it out.

  23. A couple of friends of mine had the SX 125, and another had the 175, and they were peppy little bikes, and reliable once sorted out, so years later I snapped up a SX250 with 18,000 for a measly $100, and ripped around on it for a few months before selling it for $300.

  24. Bought my first bike in 1963 that was a 1959 Harley 165. Only had it for a few months. Loved that thing but caught my girlfriend cheating on me with my friend because he had a brand new Ford convertible. Got mad and joined the Marines. When I got out I bought a Harley 250 Sprint. Liked the Harley 165 better but wished I had them both now.

  25. My first motorcycle was a 1971 Harley Davidson baja 100. I was 13 yeats old and my father and i rebuilt the whole bike. I remember the rear sprocket was a 82 teeth. I have been looking for another 1 for the past 10 years now. My father has since pasted away and i want my son and i to ddo the same thing to 1.

  26. As a HD mechanic in the 70s, I worked on quite a bit 125, 175, 250 and 350 harleys. The two stokers had good power but a moped designed ball bearing transmission and crappy electronics! The transmission was problematic and with little wear was almost impossible to synchronize. The 250 and 350 were down on power compared to the twins of the times. The big Harleys of that era warped their cylinders and would need bored or honed! Needless to say I stayed very busy!

  27. I had a 125cc just like the picture in my teens in the late 1970s/early 1980s, bought used for $500, and really burned up the trails around our house in the country. It was fairly under-powered, but did ok for what I used it for. I learned a lot fixing the various things that I broke or broke on their own over time. The lower skirt of the piston broke twice, taking it out of commission for months at a time while our HD shop ordered replacement parts. I had to tune the timing of the points (inside the flywheel – not the easiest location) every month of so, or else the power would drop off. It had a distinctive exhaust note, being 2-cycle with the expansion-chamber exhaust. I’m grateful to have had it for those years.

    • I have a 75 125 that I bought new when I was 13 years old. It was put aside when I got my drivers license. Recently I’ve been working on it. It runs but I believe the timing is off. I can’t figure out how to set the timing. I would love some help

      • Hi Scott
        I picked up a 75 175 with 4000 miles on it. It needs a rectifier on it but I might be interested in selling the whole bike. Let me know if you’re interested
        Rick Norris

  28. in 1982 and 15 years old some guy in a village not far away was almost eaten by on of his snakes. We cycled over to take a look at his house and I seen one of these tanks in the garden looking unkempt. Ended up buying the whole bike piece by piece as odd job money came in and had police chasing me within months just as planned.
    It had a strong power band which was almost motocross like. Awful electrics but that’s typical Italian auto-electrical of the era (think Alfa or Lancia)
    Sold it for £20 a year later.
    Wouldn’t by one for nostalgia. Far better bikes from that era.

  29. The 1974 125, is one of the top “I regret selling” when I went in the Army in 1975, anything I ever owned vehicles.
    Bought it new. (at a Honda dealership)
    Would love to have it back.

  30. My brother had one of these 2 stroke bikes in 1974 my mother bought it for him when he was in the Army stationed in Texas. When he got out, he rode it all the way back to California sleeping on the sides of roads with a bed roll and a few blankets. When he got back said his hands hurt for 2 days from the vibration and my mother had to get the 2-stroke engine rebuilt it was worn out. I remember the chrome heat guard along the side. I did ride on the back he took me out a few times on it I was must have been about 7-8 years old we go around the block.


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