X3viVP

Not a V4, not an inline-four. This one’s a square-four. In the mid-1970s Suzuki dropped a new engine on the 500cc class and basically ended MV Agusta’s long reign. They called it the RG500 — a liquid-cooled, 498cc two-stroke square-four that became one of the most successful engines in Grand Prix history. The layout was clever: two parallel twins geared together, rotary disc valves, and a pair of counter-rotating crankshafts that kept the vibration surprisingly low. Factory race bikes were putting out somewhere between 110 and 124 horsepower while weighing only around 130–135 kg dry. Compact, light, and extremely fast. The results speak for themselves. Suzuki took seven consecutive manufacturers’ titles from 1976 to 1982. Four riders’ championships came with it too — Barry Sheene in ’76 and ’77, Marco Lucchinelli in 1981, and Franco Uncini in 1982. The first-ever 500cc Grand Prix win for Suzuki also happened on this engine, when Sheene took the 1975 Dutch TT at Assen. In 1976, the first full year the production version was available, RG500s filled 11 of the top 12 places in the final championship standings. For years the grid was just a sea of these things — privateers loved them because they could actually compete with the factory teams. The engine's advantages was obvious. Insane power-to-weight ratio, explosive top-end, excellent mechanical balance, and a compact size that made chassis design easier. Even privateers could go fast on them. The downside? The power delivery was vicious — almost nothing below 7–8,000 rpm, then the power just exploded. Run the mixture a bit lean and it would seize without warning. Tuning four carburetors plus the rotary valves was a nightmare for mechanics. It drank fuel and smoked like crazy. And eventually the inlet design was difficult, which is why Suzuki later switched to a V4. From the mid-70s right through early 1980s, Suzuki ruled two stroke era. #SuzukiRG500 #SquareFour #TwoStroke #GrandPrix #500cc #BarrySheene #ClassicRacing #MotoHistory #VintageGP #SuzukiRacing