Yamaha SR 500
Yamaha SR 500
|Production period||1978 to 1999|
|design type||Naked bike|
|air-cooled four-stroke engine , single cylinder|
|Power (kW / PS )||17-25 kW at 6200 rpm.|
|Empty weight (kg)||169|
The SR 500 is a motorcycle model by the Japanese manufacturer Yamaha , which was built from 1978 to 1999 . As the SR 400 , it is still offered today with an externally identical engine but a different cubic capacity. The designation "SR" stands for "Single Road".
As a road machine, the SR was derived from the Enduro XT 500 , which has been marketed very successfully since 1976. As a large-volume single-cylinder, it follows the tradition of classic, especially English motorcycles, while the trend at the time was towards more powerful four-cylinder engines.
Whether the SR was designed as a retro motorcycle from the start is debatable. At that time, the term retro was not yet a concept in the motorcycle sector, and the basic design contained contemporary details such as cast wheels and disc brakes . As part of the model development, however, Yamaha later dispensed with these details and equipped the models with spoked wheels and drum brakes . It can be assumed that at least the younger models from 1984 onwards are actually the first “retro motorcycles”.
The robust and manageable technology and the large number of motorcycles sold led to the fact that the SR 500 is still a lively fan and club life. There are numerous conversions as Cafe Racer , Scrambler , sidecar , Bobber or Chopper . The model is also often used in amateur racing.
In 2003 around 20,000 units were still registered in Germany, and the trend is falling.
There were the models 2J2 (1978–1979, e.g. US market), 2J4 (1978–1983 Germany) and 48T (1984–1999). Due to legal regulations on the driver's license classes, the model is still sold in Japan as the SR 400 today (e.g. Black Edition 2008 for the 30th anniversary). From 1978 to 1999 approx. 38,000 copies of the SR were sold in Germany (including 4,767 in West Germany in 1981) and was considered a reliable touring bike despite the rather small tanks with 12 liters (from autumn / winter 1986 when the paint kit was changed: 14 liters) apart from a few peculiarities in the startup behavior. In the years before sales ended, however, new registrations fell. Most buyers expected an electric starter, and as a result of stricter noise and emissions regulations, the engine output was reduced to 17 kW / 18 kW. In the 2014 model year, the machine will be offered again in Germany as the SR 400. Sales in Europe ended in 2016 because the air-cooled engine did not meet the emissions standard that has been in force since 2017.
The engine of the SR 500 is based on the engine of the XT 500, a single-cylinder four-stroke engine with a relatively high output at low speeds. Hence the nickname "Thumper", which means something like "steam hammer" in German. Due to its short-stroke design and especially because of the two-valve technology, the maximum power of the SR is only available at speeds of around 6200 / min, the maximum torque at around 3500 / min.
Compared to the XT, the SR engine received a contactless, maintenance-free electronic ignition system, a 12-volt power supply as well as more flywheel mass on the crankshaft and a larger carburetor to adapt to the other application area . Compared to its sister model, the frame has also been provided with reinforced tubes. A special feature is the dry sump lubrication , the oil supply of which is housed in the upper frame tube.
48T models differ from the early versions mainly in the smaller front wheel and the more wear-resistant engine, which has a modified oil supply to the cylinder head for the thermally highly stressed exhaust valve and a gas-nitrided camshaft with optimized valve lift and hard-block rocker arm. The motorcycle has an air-cooled 1-cylinder, 4-stroke , OHC engine with a displacement of 499 cm³, which was throttled to 20 kW (27 PS) for the German market due to the driving license requirements and insurance classes at the time. Unthrottled, with enlarged intake and, in the 48T model, with a different carburetor nozzle, the engine has an output of 25 kW (34 hp).
At the end of production, the engine only had 17/18 kW (23/24 hp) due to stricter noise and emissions regulations, and 20 kW (27 hp) when unthrottled. A standard "newer" SR reaches a top speed of around 135 km / h, an SR 500 with 25 kW (34 PS) around 145 km / h. In late 48T models, the front disc brake was replaced by a technically complex drum brake based on the DS-7 (predecessor of the RD-250) for aesthetic reasons .
The SR 500 and SR 400 do not have an electric starter. Starting with the kick starter requires practice to avoid kickback of the kick starter lever . To find the correct piston position for the kick ( top dead center = TDC), a decompression lever and a TDC indicator window (also called a porthole) on the camshaft are used.
- The BUCHELI project: Technical FAQ based on the Bucheli repair instructions
- Webring of the SR-500 interest groups