(first posted 10/19/2011) This is what happens when you fail to stay on task: I was researching the transition of DKW to Audi, and got distracted with the fact that DKW was the world’s largest motorcycle manufacturer in the twenties and thirties. And that DKW’s brilliant RT 125 from the thirties was so advanced, that the Allies all made a grab for it, either the whole tooling (Russia) or at least the blueprints (England, US, India). And no less than Harley Davidson used those blueprints to build their little two-stroke Hummers. And then the light went on: I used to ride one of those! Time for a little more digging, and sharing.
DKW was of course the Mother Lode of two-strokes. Their very advanced fwd cars inspired the Saab and a raft of other imitators, and they continued until way too long, until the mid-sixties F102, which became the Audi when it got a four stroke motor. Let’s take that up another time. Meanwhile their radical RT 125 bike arrived in the thirties, and set the world on its ear. It was by far the most advanced light bike, and would become the most copied motorcycle ever. Why?
The two stroke engine had been around for some time, but it was typically a lazy and low-rpm, low output affair. Its most popular use was with marine engines, because the lack of moving parts made them more reliable. But the crude cross-flow porting meant inefficiency, and poor performance at higher revolutions.
In 1926, Adolf Schnürle went to work on the problem, and devised a system of ports that that created effective scavenging, essential to good combustion, especially at higher rpm. The modern two stroke was born, and Schnürle porting, along with other variations on the theme, made it possible (and wiki made these nice animated graphics possible). The DKW RT 125 was the first bike to take full advantage of it. Finally, a small displacement bike could offer decent performance. A fact not overlooked by the Allies.
The Russians took the tooling and built versions of it for decades. The Polish WFM was built until 1985! The British turned it into the popular BSA Bantam. And the Japanese copied it, and it became the first modern Yamaha (above), the progenitor of that long line of two-stroke bikes.
And in the US, Harley Davidson made good use of the blue-prints, and tooled up to produce a line of light bikes that started in 1948, and finally petered out in 1966, having been crushed by the (then) more modern Japanese bikes.
They weren’t technically called Hummers from the beginning, like this first year 1948 Model 125. And with all of 3.5 hp and a three speed transmission, the top speed was some 45 mph. But the power levels went up, a fourth gear was added, and in the fifties, this was the way to get started on a small bike. “Perfect for the paperboy”.
The HD 125 was promoted for its economical transport qualities. Eventually, that created a rut for them, as the Japanese bikes had a much more fun-loving image.
Anyway, I had owned a Bridgestone 90, a typical small Japanese/Yamaha style bike for a while. As I was on the go perpetually, it quickly went by the wayside. But the following summer, I shared a house with some guys, and one of them had a green little bike laying in the backyard that he couldn’t get started. He’d brought it from home, where he found it in a barn.
I’m not sure exactly what I did to get it running, probably a new spark plug. But I then appropriated it for myself. I’m not totally sure what vintage it was, but I seem to remember it only having three gears, and being decidedly pokier than my smaller Bridgestone 90, which could hit sixty mph. But it was perfect for putting around Iowa City in the warm summer, and it fit tall me much better than the narrow-bar Bridgestone. The little Hummer had that typical HD riding position that was intrinsically more relaxed. And it was a bigger-framed bike than the small Japanese bikes.
The only downside was that the Hummer was a one-person affair. Look, but don’t ride. My Bridgestone, small as it was, always had room for a passenger. Even if my knees were hitting the handlebars.
Maybe this is the real reason why Honda and the other Japanese cornered the market.
The actual name Hummer was adopted in 1955, for a stripped-down economy special. The name came from Dean Hummer, a HD employee or dealer, who suggested it as a way to fend off the growing Japanese competition.
Not that it did much good. Even though the Hummer grew to 165 cc, and a whopping ten horsepower, Harley Davidson was unable to make it work, given that US wages were so much higher then. And the competition was constantly upgrading and improving, which was making the Hummer look more like the thirties design it really was. This 1962 Pacer was obviously trying to evoke the big Harleys.
And the very last of the series, the 1966 Bobcat had a stylish fiberglass one-piece “body kit” to make it look current. But by then America was awash in Hondas, Suzukis and Yamahas. HD ditched the little Hummer, and never looked back. Its future lay elsewhere.
(Pictures and facts courtesy harleyhummer.com)
very cool… I always remember Harley’s dabbling with Aermacchi… especially the 350cc single with forward-facing cylinder… we occasionally saw one or two burbling around Los Angeles… HD kept trying to break into the small bike market, but they just didn’t “get” it, the way Yamaha or Honda did (my first bike was a Kawasaki 100 Enduro, a very nice little 2-stroke, which continued on for many years)… what would have happened, if the folks at HD had created truly competitive small bikes?
Yes, the HD Sprints; another sad but interesting story.
Had use of a 125 Aeramachi 1973 not much to recomend it. It cames as a set of 2 make it go you can ride it easy enough to fix but not very much speed/power.
Here is a very custom hd super10
Well Paul, I for one, would like to invite you to tell the story of the HD sprint. I owned one and IIRC it was a 250 from 64 or 65. Perfect little brother for the Harley as it vibrated and was hard to start. Ran good when you got it started.
I did not know that they were still building the two stroke when they started selling the Aermacchi. BTW that antimation gives a perfect example of why an expansion chamber is much like a turbo for hopping up two strokes. I often wonder what would have happened if the US had embraced the ringadings in the same way they did the overweight hogs. I think the most interesting, logical, and all around first choice of all the bikes I have owned would have been the 350 Jawa Californian. Cruised all day 70mpg and 70 mph.
If a young lady and myself had not sought seclusion at La Playa beach in Panama and wound up getting the bike underwater with salt water, I think I might have gotten my moneys worth out of it. Actually, perhaps I did. Youth!!
You drove the Jawa to the Panama? Maybe not. But sounds like quite a story.
Maybe you’d like to write the Sprint story. I could use some more help here…
Yes, I’d love to read the Jawa story! Czech bikes are awesome.
That animation got me thinking too. I wonder if a revival of the 2 stroke is possible. Direct injection could eliminate the scavenging losses of fresh fuel. Imagine the engine inhaling fresh air only and the fuel being injected as soon as the exhaust canal is closed by the rising piston. I imagine lubrication by an oil pump with a version of a dry sump. A catalytic converter would eliminate the blue cloud and other nasty things.
Here is a fuel injector detail:
Keep the faith, brother! I think about this all the time while riding my carburetted 2-stroke Yezdi motorcycle.
More realistically, perhaps the only production vehicle with direct injection two-stroke tech is the Bajaj Auto rickshaw here: http://www.bajajauto.com/comm_psngr_re_gdi.asp
Considering that Bajaj is India’s second largest motorcycle manufacturer, if there is any market for this in a bike they’ll do it.
Harley did try to keep up with the world at one stage but the just went back to their primitive Vtwin and cried poor me. Theyd be gone but for a tarriff wall erected for them to hide behind even their race victories were only due to punitive handycapping. Positively the WORST motor cycle the planet has seen.
Its painfully obvious that you’ve never lived with one. While my main love will always be Triumphs, I’ve had a few Harley Davidsons (there’s an ’88 FXR Super Glide sitting in the driveway, waiting for me to finish this so I can put Maggie on the pillion and take off for the afternoon). And I’ve loved every one of them.
Yeah, they’re down on performance if you’re totally hung up on Ducati’s and Kawasaki sport bikes (I’ve had a few). But for an enjoyable, relaxing day’s cruising and just eating up the miles there’s aren’t too many bikes that are better.
Of course it’s what you’re looking for in your ride. If you’re into BMW E30’s, a Chrysler New Yorker is going to be one hell of a disappointment. Likewise the Harley as a motorcycle. It’s not a sport bike, its a cruiser. Ride it as such, an they’re a wonderful definition of heaven.
There’s a reason there’s so many Harleys on the road. They work. Quite well.
3.5 horsepower? 3 speed transmission? My 75cc Honda XL had them beat!
same model year?
That was 30 years later and shows the technological progress.
Compare to the Yamaha DT 125 which has a single cylinder 2 stroke:
13 hp and 6 speed transmission.
My first (and last) Harley was a 50cc two-wheeler that I got at Sears. I was under the impression that it was Italian-built; certainly it was very, very orange. Just like a mo-ped without the pedals, though hill climbing with two aboard made me wish I could have pedaled to help that lone struggling cylinder. It had handlebar shift, and you mixed oil with gas. Not often, since the 2.5gallon fuel tank (IIRC) only needed filling a few times in the six months before I’d aged enough to drive my mom’s Mustang, and I set the Harley aside.
In Tennessee circa 1968, the first license you could get was a sub-50cc motorcycle permit. That had its benefits, for us survivors, anyway. Such a paucity of power taught me humility, caution and tactical planning. It was a fun ride, but the name was too much to live up to. It was only half-a-Harley, if that much, but I had only half a license, so it all made sense at the time.
Thank you Paul. Not every Curbside Classic has to have 4 wheels. Or 4 cycles. Or even internal combustion. Vintage Schwinn week soon?
If you do, I’ve got a load of stuff to talk about.
I’m working on a vintage Raleigh post right now – assuming Paul/Perry approve (and I have no reason to think they won’t).
I was too young to get in on the small Harley craze…but my first bike was a two-stroke Yamaha R350C. Only a little bigger than the Hummer; but worlds apart in power.
It was a 1972 that I bought for a hundred bucks in 1985 – and it was pretty beat. Just the same, it was a gateway drug…
Never went the Harley route. When I started, the old Harleys had the AMF stink on them…Hardly-Dangerous. The new ones hadn’t made their mark yet, and when they later did, the price was moving up exponentially.
My current “big bike” is a BMW R1200GS – and no, I wouldn’t trade for a Harley anything. Harley went in a different direction…from American cutting-edge to neglected product de-evolution, to expensive retro.
I don’t care to pose retro. I choose to ride. But, anyway, good glimpse of history…
Harley Hummer Knuckle Single
Cute bikes,never seen one in the metal but in the 60s and 70s the BSA Bantam version of the DKW was a very common sight in the UK.
Paul: I am in heaven today.
DKW made a larger version of the RT 125: DKW RT 250.
Herr Janoschke had one of those. He lived in a rental apartment in my aunt’s house. The motorbike was not working anymore but we took it out of the barn and rode it in the yard powered by 3 boys pushing. The Janoschkes built their own house nearby and took the motorbike with them. It moved from the barn into the basement. About ten years later it was still there. A friend of mine was interested in old motorcycles. One day we visited the Janoschkes and my friend was able to buy it. He restored it and it was the first of a collection that grew to 100+ motorbikes.
I love the old Harley ads- so full of clean cut,responsible youth, and older pillars of the community! So different to the faux-badass look of today…
Imagine the outcry today if you showed an ad with kids riding with no protective gear!I like the old ads a lot also,Hummers are cute bikes.
Spot on. I have to laugh at the mandatory black jacket, black open face helmet,
“We’re all bad ass individuals. Who are so bad ass we wear a uniform”
Still, I bet the 2 stroke sounds better than that tractor noise one hears
from the V twin.
Sister bike to the BSA Bantam. Hummers were actually raced in enduros and scrambles in the 50’s and there was a rear suspension kit available. Conventional wisdom was with the large 4 stroke machines but these were the tip of the spear for the later Greeves and CZ and Bultaco 2 strokes that came to dominate the sport. I am a 2 stroke hold out and have a 250 KTM. In tight twisty conditions they are still the bike to beat. The Euros have held out with 2 strokes with KTM (and Husky), Beta and Sherco models available and I believe that the revived OSSA has an injected 2 stroke trials bike.
Nice article ;
I’ve had some ‘ Two Smokes ‘ and they were just fine for what they were .
I also had a 1937 EL (61″) Knucklehead and a 1965 FL (low compression 1200) PanHead Harley , both purchased back when no one cared about old Harley’s , I restored and rode the living crap out of both , good Motos in their own right .
Once I decided I wanted to ride faster I moved on from H-D Products , I’d still like a ’55 K Model if ever I win the Lottery .
The current crop of henna tattoo wearing poseurs at least kept Harley in business , be very glad for that .
As always , the B & B’s stories make this a top grade thread .
+1 on K models I got interested in them when I saw a picture of Elvis on one.Without the k model there would be no Sportster the best street HD of them all
Grandpa had a 1962 Hummer. He was a old rider(when I was born he was 48 and was a WWII vet) and gave it to me for my 15th birthday. Was a great bike but I crashed it in the early 90s and all I have left is the gas tank sitting in my barn
Does anyone know where I can find the story of the three guys on Hummers traveling from mid America to the West Coast? I read it once and should have printed it out. Tells of their trip and tribulations, a wonderful account of all the breakdowns, repairs, pushing their bikes up hill on the mountains, etc.
Tough to find a clipping/ad you didn’t already have, Paul. I came of age when you did, and remember the Japanese bikes bringing a great value–and of course a carefully cultivated image–to the U.S.
I hadn’t thought about the HD’s handicap of no-passenger; Honda smartly played that up in its advertising, for sure!
^^Picture didn’t get snagged?
Scott Summers used to pick up his Honda XR600 just like that, quiet a bit heavier than the little Hummer! He became a hero in Japan for this feat. He was a pretty big dude for an off road racer.
2 stokes forever. I’ve been to Pro Motocross races an Southwick and Unadilla and seen spectators with rev’d out chainsaws (sans chain BTW) pumping up the crowd at the start of the races. Angry beehive noise really incites people.
Back in the ’50s HD and other manufacturers of bigger bikes thought that a small bike was a passing phase in a rider’s career. They figured that they would trade up to a bigger bike pretty quickly. The Japanese on the other hand, built newer and somewhat larger versions of their small bikes and riders traded up within the marque. This created brand loyalty. Over the years I rode 50cc, 160, 305, 350, 450, 750,and 1,100 cc Honda models. I had a Kawasaki, Suzuki and several Harleys also. I think that smaller bikes can be fun and economical without the need for so much ego involvement.