Big-bore single-cylinder motorcycles with four-stroke engines were very common in the early decades of motorcycling. Big British thumpers were probably the best machines in this category, and as that country’s moto production industry died away through the 1960s and 1970s, so did the idea of a big four-stroke single. People wanted multi-cylinder bikes now, like the CB lineup from Honda or Kawasaki’s KZ series. Rotax made a big 500 engine, but almost all other 500 singles were about half that size, max—machines like the XL250 series. And then in 1975, Yamaha brought out the XT500 dual sport, followed by the TT500 trail bike and the SR500 street bike, one of the most influential decisions this manufacturer ever made, inspiring decades of single-cylinder production from Japan.
首先是XT500,。这种大口径dual sport could arguably be called the first adventure travel bike, or at least held on-par with the Honda XL250 in that regard. These machines were reliable as an anvil, serving as the basis for many race machines in the early Dakar raids. The SR was coming from a very strong lineage. Photo: Yamaha
Street vibes
Yamaha actually introduced an SR400 and SR500 in 1978. The SR400 had a shorter stroke, but was otherwise identical to the SR500’s air-cooled single-cylinder engine, which had 87mm x 84mm bore-and-stroke for 499cc capacity. With a single overhead cam and two-valve head setup, this bike was very much built for lower-end torque, not a high-rpm screamer. Claimed output was 31.5 hp at 6,500 rpm, and 26.8 lb-ft of torque at 5,500 rpm.
Styling was contemporary, along the lines of other UJMs of that era. And yet, even as early as the late 1970s, the Japanese had begun to take pains to style their bikes more and more like the classic models of their American and British competition. Until the XT500, Yamaha’s best-selling four-stroke was the XS650 series, which was essentially a modernized Brit bike design. For that reason, the SR looked a lot like an XS and the company told its dealers that the styling was Brit-bike inspired. I think this resulted in quite a bit of the company’s success in following decades, as Yamaha has always been good at building good bikes that draw heavily on inspiration from other countries (see also: the Virago lineup, the V-Star lineup, etc.).
Because big singles are hard to start, Yamaha put a decompression lever on the head, and a sight glass. Riders could turn the engine over carefully until the sight glass indicated it was at TDC, and easy to start. Jump on the kickstarter, and you’d be rewarded with a stiff blast of single-cylinder exhaust note. In reality, this was a feature needed only by newbies or the inept. Any motorcyclist with mechanical sympathy could step lightly on the kickstarter and tell pretty quickly what was going on inside the engine. Even so, the TDC sight glass remained on SR-series bikes until the lineup ended production in 2021.
An electrical boot might have made life even better, but Yamaha resisted this idea, for reasons that aren’t clear. At least it kept the bike’s weight down; the SR500 weighed around 380 lb at the curb.
Yamaha’s early sales brochures show a machine that looked a lot like an XS650 (and also the XS400, which was in production at the same time). Unlike the fiddly 400, the SR500 had the same reputation for reliability as the 650. Maybe even better, as the SR was built in-house, not adapted from a purchased design as the XS650 was. Photo: Yamaha
Big in Japan
The SR was phased out in the US in the early 1980s, but sales continued in Europe for many years. When the carbureted SR500 got the axe, the Japanese continued their own domestic production of the SR400, which ended up getting EFI to keep it emissions-legal. Eventually this new fuel-injected SR400 was re-introduced to the US. Sales ended worldwide in 2021.
What made the SR series so popular? It had two things going for it. The bikes were proper full-sized motorcycles, with all the torque you needed, but they weren’t heavy. Just like the big Brit bikes they drew inspiration from, the SR series were great all-rounders; easy to live with in the city, fun on a back road, just enough power to take the four-lane when needed.
The other big selling point was the machines’ simplicity, which made it easy to customize them. When the SR400 came back into the US market, it was a darling of the Japanese custom scene, and presented to US buyers as a great machine to turn into a cafe racer, bobber, whatever. But it was expensive, and I’ve never seen one on public roads down in the States. Yamaha never even bothered bringing them into Canada on this second go-round.
ADVrider inmates occasionally post up threads on the SR500, including DIY customs. See a lovely scrambler conversion from @jankhere.
This bike was for sale on the Flea Market sub-forum, but then the seller changed his mind. Throw some cash his way, and maybe you can change it back? These really are becoming a rarity, and street-biased single-cylinder machines have never really been common in the US for decades anyway. Photo: @brucifer
This bike here
Inmate @brucifer had this 1981 model pictured above for sale, but it looks like that plan is on hold for now. His advert read:
Beautiful classic last year of the SR500 in the States.
Runs and rides excellent. It does have some cosmetic issues having spent its life in the Humboldt Bay region, but still shows well. One small dent in the left side of the tank.
Very low miles at 9,400.
Kick start only and will typically fire off on one to two kicks cold and one warm.
Has Progressive Suspension rear shocks on the bike. The stock shocks are included. Stock exhaust is on the bike but a vintage chrome White Brothers complete exhaust system comes with it, however it is rusty and needs to be rechromed or stripped and painted.
Factory owner’s manual and Haynes service manual included.Clean title in my name and currently registered.
$2500
Located in Eureka, California.
The ad now says“Withdrawn from sale.”Maybe send him a PM if you might be interested in changing his mind?
If he won’t change, then you can find a much newer, much more expensive SR400 (with fuel injection, remember) for salehere.
