TSS RS500GP

I can imagine how the converstion between Wayno and Stevo went (well they are from Far North Queensland). That is Stephen Rothwell and Wayne Wright from The Two-Stroke Shop. It’s safe to say it ended with “Let’s build the bike that should have been”.

They set about getting a 500cc two-stroke built to slip into Apilia’s RS250 frame. The RS250 is an excellent bike. It’s good looking, has great handling and will stop on a dime. But! There’s always a but. In standard trim it’s powered by a Suzuki RGV250 engine. Not that the engine is all that lacking and can still scare most people, this bike with a 500cc 2-stroker now becomes a capable weapon ready to tackle modern 4-stroke sport bikes.

 

The RS500: Ultra-Light, Massively
Powerful and Grand Prix Engineered

The TSS RS500GP represents for us, and for a great many sports motorcycle enthusiasts, the ultimate ‘Bike That Should Have Been Built.’ A rip-snorting dream bike with more grunt than a piggery at chow time, and with a singing top-end power hit to silence all two-stroke naysayers.

Well, now it is being built. And the best news is that it is developed, tested and built by a 500cc Grand Prix Engineer. Yet the RS500GP is more affordable than a middleweight Superport four-stroke. That’s because we at TSS are phenomenally passionate about advancing the cause of the two-stroke road and race bike.

We have made it our business to sucessfully produce a viable alternative to the four-stroke sportsbike status quo, so our customers can enjoy the sharp crack of high-density power that only a two-stroke engine can provide.

Yet all of this started off humbly enough, as a simple plan to try out a Cheetah 485cc engine in an Aprilia RS250 chassis. The plan paid off, big time. And word got around about the spicy hybrid, and excited emails and ‘phone calls came in day and night from all over the world, and with almost evangelistic zeal they said, “A modern 250GP style bike with a 500cc two-stroke engine!? I want one; I want to build one; just don’t tell the missus!”

It was like a scene from Monty Python’s ‘The Life of Brian,’ with all these two-stroke starved pilgrims looking for a Messiah. And the truth is, you just about need a miracle to engineer one of these things properly, or at least a miraculous overdraft. The cost to develop a bike like this to the highest standards is far beyond the budget of all but a few wealthy individuals, but everything is just so right about the bike; more people deserve to enjoy the ride.

Fortunately for the two-stroke fraternity, a chance meeting with famed Grand Prix Engineer Wayne ‘Wobbly’ Wright unlocked the key to really perfecting these promising hybrids. Over a career spanning more than 30 years, Wayne has designed and built and tuned the best. As a 500cc GP Engineer, he built race-winning pipes for the Red Bull Yamaha racing team. His engines and pipes and ignitions have won GPs and Championships all over the world.

And what Wayne saw in the early RS500 was a devlishly brilliant scheme in the making. He saw the potential for building an epic canyon-blitzing steed that Yamaha’s and Aprilia’s engineers would loved to have built, if the bean-counters had allowed them. A true no-holds-barred two-stroke rocketship with a fat bottom end, massive midrange and lung-collapsing top end rush.

The RS500GP went into development and testing. The Two-Stroke Shop (TSS) was born, and with it the world’s first Direct-to-Customer GP Engineer-Developed Motorcycle. The RS500GP ushers in an exciting new concept: for the first time ever, the pure undiluted two-stroke GP experience is available for all road and race riders.

The whole engine was redesigned and optimised – (please CLICK HERE for more detail on TSS500 engine development and technology) the whole inlet tract was custom-built, flow-matched and set at exactly the right length, just as a 500cc GP machine would be prepared.   

Custom-designed, lightweight Wossner flat-top race spec pistons were forged, and crankshafts manufactured to precisely the right Balance Factor for the reciprocating asemblies used. This exacting process of balance-matching all engine components is more typical of MotoGP pit lane, but it’s just another example of TSS’s relentless pursuit of excellence.

The end result is far more than a mere race replica. Combining the massive grunt of TSS500 power mated to the unbeatable chassis of the flyweight Aprilia RS250, like peaches and cream we have a match made in motorcycling heaven.

After building the first few RS500s and seeing how great they are, we decided to produce a large batch of components and offer the RS500GP as a production bike, along with TSS500GP engine kits as well as its stablemate the TSS500LC.

We believe a sportsbike should have the ability to render you a breathless, raving gibbering fool. A bit like a teenage girl at a boy band concert, but with the difference that this is a relationship that does get consummated.

We believe motorcyclists deserve a truly exhilarating ride – and the RS500GP is The Ride of Your Life.

Just take a look at this dyno chart; it reveals that the TSS500GP engine developes some 30% more torque than a 600cc Supersport engine, in a bike that is 35kg lighter!

The raw numbers alone – well they just stack up. A 112HP engine in a 130kg bike, with two mighty 250cc pistons churning out gutsy torque even at low revs.

This is not like the old-school four-pot 500s with their tiny 125cc cylinders and consequently ‘boggy’ lack of response when off the pipe.

Just think of a bike with 2 x CR250 motors, and you’re getting close to understanding how strong the TSS500GP mill pulls from low revs.

And yet, due to our revolutionary new curved power-valve blades that follow the piston profile more closely than existing flat-blade designs, the strong bottom-end and midrange grunt is achieved without compromising top-end zing.

So you get all the righteous benefits of the two-stroke engine – an avalanche of torque straight off idle, building through a rollicking midrange and culminating in a classic two-stroke whack over the head top-end rush.

So never mind the enviro-hippies and the adherents of ‘predictable, controllable, linear four-stroke power.’ No, it’s time to take this beast to the streets and the tracks!

The best deal of all is that this project paves the way for anyone who is interested to get into their own RS500. We can supply complete RS500 bikes; everything from chassis, engines, etc – or we can adapt your existing RS250 with a custom engine mounting cradle to accept the potent TSS500GP engine.

Whether you fancy the ultimate two-stroke track-day tool or indeed the last word in a canyon-blaster, look no further, because the RS500 is here to satisfy your every two-stroke desire.

This is not just a Performance-Enhanced Blast Down Memory Lane – these engines usher in a whole new era of two-stroke technology and performance – the long-awaited age of the Two-Stroke Superbike! Suspension and tyres and brakes have evolved – now let’s bring on the power!

All enquiries about RS500s/Kits/Parts, including TSS500 engines; expansion chamber exhausts; RS500 engine mounting cradles; offset sprockets; Ignitech ignition systems etc. to Steve at offbeat@iinet.net.au please. Tel. 0427 774 285 or from outside Australia: +61 427 774 285.

The Two-Stroke Shop is also making high-capacity radiators, designed for running TSS500 engines in the RS500 as well as the Yamaha RD/RZ chassis.

You are welcome to get in touch if you would just like to chat about the bike or bikes in general, especially two-strokes!

Source: The Two-Stroke Shop (Editor’s note: there’s plenty of information on the TSS 500LC & TSS 500GP engines too.)

Suck, squeeze, bang, blow is overrated.