We’ve heard rumours that Suzuki will join the ranks of Supersport 300 manufacturers in 2019 with a new GSX-R300 sportsbike, and this patent could be the first sight of its new challenger.

Sure, Suzuki already has a small sportsbike, the GSX250R, but it is a low-performance machine that’s little more than a GW250 Inazuma with a fairing. What this patent reveals is a very different proposition.

The new bike will be powered by a parallel-twin engine that is surely around the 300cc mark, and possibly higher. It’s clearly a machine in much the same mould as the 321cc Yamaha R3 or Honda’s 249cc twin-cylinder CBR250RR.

Given that Suzuki developed new 124cc and 147.3cc single-cylinder engines for the GSX-R125/GSX-R150 models, it’s likely the new parallel twin will share similar internal dimensions. Both those new singles have a 62mm bore, Suzuki altering the stroke to suit local regulations. Pairing two 62mm-bore singles would again give Suzuki a selection of capacities for varying markets by merely adjusting the stroke.

Suzuki has filed two patents showing the new bike, both of which centre around relatively mundane aspects of the machine; one relates to the air cleaner design, the other to a fuel pipe system that allows the tank to be hinged at the back.

The patent is very specific about the new bike’s engine, though. It clearly states that it’s a parallel twin – as can be seen in the pictures – and also that it’s ‘of high power’.

Also shown is the bike’s styling, which is very much in line with the design themes of the smaller GSX-R125. There’s a single front brake, with a radial caliper – the mounting is visible even though the disc and caliper aren’t shown in the drawings – and the shape of the swingarm suggests it will be aluminium. 

Chassis is tubular steel, with twin upper tubes on each side of the engine connected by trellis-style braces. A pressed steel section connects them to the swingarm pivot and the seat subframe.
A twin-cylinder engine with the same 62mm x 41.2mm bore and stroke as the GSX-R125’s single would have near-identical internal dimensions as the Honda CBR250RR, but adding the GSX-R150’s 48.8mm stroke would increase capacity to 295cc.

For those who like to go naked

Suzuki also plans to launch a naked GSX-S300 model. In issue 67-20 we revealed the Haojue HJ300 that might be related to that machine, but the HJ300 uses an enlarged version of the older parallel twin that has a relatively long-stroke, low-revving design. This GSX-R300 patent shows an entirely new short-stroke engine that’s likely to offer much more performance. Whether the eventual GSX-S300 naked bike turns out to be derived from the Haojue HJ300 or is a naked version of this higher-performance GSX-R300 design remains to be seen.

Ben Purvis