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Motorcycle profile – Suzuki RG500 Gamma 1985-87

by Guy 'Guido' Allen

August 2020

Suzuki RG500 Gamma

Gamma racer

Doomed to failure or just unlucky timing? Suzuki’s ultimate GP replica from the 1980s has a lot to offer the collector

Suzuki RG500 Gamma

There was a time well within living memory – say the late 1980s – when retired and outdated race bikes, like a RG500 GP machine, were cheap. Expensive to run and with no apparent future, you could pick up a decent one for about the price of a mid-level road bike.

At the same time, the just-discontinued RG500 ‘Gamma’ road equivalent was plummeting in value. In just a few years, you could buy one for a song. How times have changed.

Now the GP bike is worth serious collector money – depending on its history – while a good roadster is about the same price as a decent modern sports bike and rising.

The story of the Gamma is one of the great examples of how fickle the motorcycle market can be, and how, sometimes, manufacturers end up shooting themselves in the foot in the rush to fill every known niche.

Thinly disguised
First shown in 1984 and launched for the 1985 model year, the Suzuki RG500 represented a new philosophy for Suzuki – one which said it wasn’t afraid to inject a lot of race DNA into its road bikes. Its other great model of the period, the GSX-R750, is the epitome of that direction with its thinly-disguised endurance racer spec.

With the benefit of 20/20 hindsight, it’s hard to see how the RG could have survived in the showroom environment of 1985-on. This is a period that saw the most fierce ever competition between the big four Japanese makers (Suzuki and Yamaha in particular) to the point where rumour said at least one of them went close to going broke.

In the sports bike arena, models like the Kawasaki GPz900R, Honda VF750F, Yamaha FZ750 and Suzuki GSX-R750 were the headliners. To make matters worse, Suzuki’s feisty RG two-stroke was beaten to market by Yamaha’s RZ500 GP replica – by a year.

And then, at a time when the new four-strokes were the big news, Suzuki initially priced its RG500 higher than the GSX-R750 – $5799 versus $5699. The RG500 really didn’t stand a chance.

Despite all those problems, over 9000 are said to have been built across the 1985 to 1987 model years, with another 6000 400-class versions for the Japanese market. In Australia, sales were extremely sluggish and the bike was discontinued in 1986 at a retail price of $4599 – a hefty discount on the original sticker.

Suzuki RG500 Gamma

The package
So if you were brave enough to order an RG, what did you get? Though Yamaha and Honda had recently overtaken Suzuki on the world’s GP circuits, the Hamamatsu firm still had plenty to celebrate. It held the 500cc GP constructor title from 1976 through to 1982, while its most recent rider gongs were with Marco Luchinelli in 1981 and Franco Uncini in 1982. In the west at least, it was cheeky Briton Barry Sheene who really set the brand on the path to fame, by taking the 1975 and 1976 titles.

Like the race bikes, the RG boasted a two-stroke square four powerplant – unique in the road bike world. The nearest thing in living memory was Ariel’s square-four four-stroke of the 1930s to 1950s, but that had few race pretensions.

Liquid cooled and running rotary valves, the engine boasted flat-slide carburettors and some sophisticated thinking when it came to controlling breathing.

On the intake side, the cylinders on each side were paired with a common chamber claimed to ensure smoother and more economical running. On the exhaust end, we scored servo-actuated sub-chambers that effectively altered the exhaust ‘shape’ depending on where the bike was in the rev range.

That little lot claimed an impressive 94 horses in a package listed at just 154kg dry. We’re talking very serious performance in a compact motorcycle.

The transmission was a six-speed cassette-type with wet clutch, while the chassis was typical for the day. What now looks like a spindly alloy frame was held up by a fork with an anti-dive system and a Full-Floater monoshock rear end. Wheel sizes were very mid-eighties: a 16-inch front and 17 rear running narrow 110/90 and 120/90 profile tyres.

Suzuki RG500 Gamma

In the flesh
So what were they like? I happened to be working for Australian Motorcycle News when these things were launched and, even then, they were weird cattle. Two-strokes were much more common on the road (the steam age had passed, in case you were wondering…) but pukka race replicas of this magnitude were restricted to a class of two in Australia: this and the Yamaha's RZ500.

Little and light, it was easy enough to handle and far less flighty than the Yamaha. Braking was sensational and you got the distinct impression you could make some very late decisions on this motorcycle and get away with it.

And yes, it was fast. Enthusiastic throttle use would see the front wheel getting light in the first three gears, ensuring the little beastie had your full attention on a sports road.

A modest cult has built up around these machines over the years, so there’s quite a lot of tuning knowledge out there, even if they’re not the easiest things in the world to work on and are probably beyond the scope of most recently-trained mechanics.

It’s one of my two all-time favourite two-strokes – the other is the Yamaha RZ350 – and, even at the currently inflated prices, still represents good performance for the dollar.


Yamaha RZ500

The other stroker
Launched a year earlier than the Suzuki, Yamaha’s RZ500 (above) featured a similar level of sophistication and complexity, though the big difference was it mirrored the corporate GP machines with a V-four engine layout.

It was a little heavier with a little less power (173kg and 88 horses) than the RG, but was still a fearsome bit of kit with a top speed in excess of 220km/h. One thing to watch with this model is that poor chassis set-up can alter its handling for the worse, something which quickly tarnished its reputation. Stability over rough roads was an issue and something to be watched for.

For years RZs were more valuable in the classic market than an equivalent RG, but that gap has narrowed over time to the point where it probably no longer exists.

Suzuki RG500 Gamma


Suzuki RG500 Gamma 1985-86

Type: Liquid-cooled square four two-stroke with disc-valve induction
Bore and Stroke: 56 x 50.6mm
Displacement: 498cc
Compression ratio: 7:1
Fuel system: 4 x flat-slide carbs

Type: 6-speed constant mesh
Final drive: chain

Frame type: alloy
Front suspension: Conventional 38mm fork with adjustable anti-dive and preload
Rear suspension: Monoshock, preload adjustment
Front brakes: 2 x 260mm discs, 4-piston calipers
Rear brake: single 210mm disc

Dry weight: 154kg claimed dry
Seat height: 705mm
Fuel capacity: 22lt

Max power: 94hp @ 9500rpm
Max torque: 71Nm @9000rpm

Price when launched: $5799 plus ORC


Loads of performance
Light and nimble

Not so good
Becoming expensive
Specialist workshop knowledge required


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