10/23/2008 @ 2:56 am, by Steve TLS16 COMMENTS


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.

73mm Flatop piston

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!

TSS RS500GP Dyno chart

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.

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  • Jiri Matousek

    Hello,it is posible to buy somewhere this bike?Thank you

  • Marcus

    This Has been going since 2008. One would think after reading their blurb that these guys invented the twostroke. NOTHING new has been done here. people have been putting Banshee Cheetah motors in Rs’s and other things for ages. As for Wayne Wobbly Wright “GP designing” the Chambers well anybody can do that. just get the book Two-Stroke Performance Tuning Performance book by A Graham Bell… You too can “Design Chambers” sure not everyone can fabricate them but i sure as hell can design one and there are plenty of guys out there who can Fabricate them for me. Are they Making their 90 degree crank from scratch…no they’re sourcing them just like you or I could..
    Funny it’s 2010 now a lot of people arfe putting up their hard earned money yet even at this poin(Late Jan 2010). No direct test or comparison with a modern 600 or anything for that matter has been done Just some crappy video on Youtube. Whats the matter boy’s what have you got to loose?

  • Anybody can design an expansion chamber? Well, I guess so.. just like anybody can paint a photo-realistic self portrait! Just get some paint, a canvas, look in the mirror and have a go. It’s just that easy!

    Isn’t it?

    From your ridiculous comments I’m willing to bet a few bucks that you have never designed pipes for a 2T. ?

    So. If I were going racing and looking for the most efficient possible way to operate for a season and lap quickly, I’d be on a 600, no question. As it is, I race/ride for fun and I’m on an RS250R, just for the sheer joy of riding it. I’ve done my time on a string of i4 600s. An RS Aprilia with 112 HP sounds like a hell of a fun time on a racetrack- my bike, plus 35 more HP? Yes, please. I couldn’t give a hoot if a CBR600RR can cut a faster laptime. I want to have as much fun as possible, end of story. And this sounds like a fun bike.

    The individual components may not be earth shattering. But has anyone else built a new, no-compromise 2T lately? And not some bastard garage-built special, but a bike that (hopefully) will hold together, run hard, carburete well, and handle like a real racebike? That’s what’s exciting.

    TSS do not seem like vaporware, and a lot of us are anxious to see what the end result will be. But yeah- I hear you- let’s see this thing running and chewing up a few tires. I think they’d rather err on the side of extra development, than “pull a Bimota” , so if it takes them an extra year to get it 100%, so be it. RN

  • Marcus

    Well the I guess you’d be loosing that bet then because as a matter of fact I have designed(and fabricated) a set of chambers for my open series rz350 powered Go Kart, using the book I quoted above as a guide. Guess that makes me more of “GP” chamber designer than you eh?

    “The individual components may not be earth shattering. But has anyone else built a new, no-compromise 2T lately? And not some bastard garage-built special, but a bike that (hopefully) will hold together, run hard, carburete well, and handle like a real racebike? That’s what’s exciting”.
    Read the latest UK PB I think you’ll find a RS535 that stan stephens has been racing for some time now

  • Yes, anybody that can handle a calculator and has read Jennings or Bell can come up with an expansion chamber design. Or, you can get software from any number of sources and generate a pipe design that way. I have TSR, Dynomation, MOTA, and SoftEngine packages, and have used all of them to do pipe and engine analysis.

    I’ve built several sets of expansion chambers as well; however, instead of assuming that I’m now a GP pipe designer, I now realize that there’s always a better design out there. And the pipe design I spit out using TSR just maybe won’t be as good as one that comes from a guy who designed pipes for competition at a world level. Call me crazy. There’s a lot of subtlety in making a pipe, and knowing how to optimize for a particular engine is trickier than using a tuned length formula.

    You have two RZ350 engines, with the same port timing. both have same projected peak RPM. OK, so you come up with a pipe design. Now, what if the transfers are changed to flat-tops? what if compression is raised? what if he stuffs the crankcase? what if he’s going to race at high altitude (Pike’s peak). How do you alter the pipe to optimize for those changes?

    That’s when a guy like Wobbly is probably going to know which direction to go, while the book is going to hand you the exact same pipe design you started with. That’s all I’m saying. I have always sought advice from more experienced pipe designers, when I can get it, because they have insight and experience that I lack. The book is a starting point. A lifetime of experience is worth a little bit, no?

    I heartily commend you for designing and building your own pipes, of course you know that puts you in a pretty small minority as far as 2-stroke self- tuners go.

    We won’t get the latest PB for a few weeks, probably. I’ll have to check it out! My buddy built a similar project, with 480c monoblock RZ motor in an RS chassis. I haven’t ridden it yet, though. I have not heard a peep about Stan’s 535, is it a one-off toy or something he plans to market in quantity?

    I still think it’ll be something fantastic if TSS can get this bike in people’s hands in some quantity. Lets face it, interest in 2 strokes is dwindling fast (at least stateside) and if guys were out doing trackdays on a good looking RS500GP maybe it’d spark an interest in a few 4T guys.

    I ride, race and do trackdays on an RS250R Honda, it goes well but I think it’d be even more fun with 35 more HP. Guys in the pits are always interested in the little screaming bike that got round them in the last session. But not enough to make them go buy one. So I’m very keen to see what TSS achieve with this bike. If I said, “yeah, it’s an XYZ500, you can go buy one yourself” just maybe they’d have a look into it.

    I have an RG500 but it’s so old, and parts so scarce, the thought of a new machine with available parts like the RS500 has got me going. What can I say.

    Peace, brother!

  • Marcus

    No Randy I don’t want a flame war. My point is in any manufacturing business you do the R&D before you anounce a new product not announce it and then leave the punters drooling for two years until eventually people loose interest. I too have raced two strokes, back in the day. I have an 08 gsx-r and would buy one of these things in an instant if I could get more info on it, but apart from a very glossy website there seems to be jack-shit info on a real life working model. If it’s still under development then don’t announce that it’s ready for the public to purchase. I would love to have one of these in the garage, I would also like to ride to work on a Unicorn. Up to this stage in time both these methods of transport seem as feasable as each other..

    peace out

  • I hear ya. It’s a balance between generating interest pre-launch, and stepping on your d*** if you don’t bring it to market in time. Look at Boeing and the 787.

    I’m trying to stay upbeat bkz there aren’t many guys trying to do this. I believe they have a US distributor now..??

    Rick Kovacic of sportcycle racing said they are going to take an RS500GP racing with the AFM this summer (California) and that the prototype was being assembled stateside.

    Santa Barbara, California

    I invited them to bring an RS500GP to an AHRMA event at Barber motorsports park, but that will be later this fall. We’ll have to see what happens. Maybe the light is at the end of the tunnel? Sounds like it is available for sale?? I have not heard from any current owners, tho.

  • I can asure you this bike is real,and both steve and wayne know very well what they are doing,those of you that want to mock these guys,please show us your custom built bikes,and chambers,these guys arnt talkin, theyre doing.

    I am currently building a 500 cheetah going in my RZ,steve has been a wealth of information and advise,and hasnt tried to push me to purchase any of their parts.

    I have been building and racing rd’s and rz’s for over 20 years,and know horse shit when i hear it.

  • Hey, I’m not mocking TSS! I’ve chatted with Steve several times, the bike sounds fantastic, and I was pretty clear that I’d like to own one. It’s not a jab at TSS to point out that the frenzy for this scooter is going to start to slide if we don’t see them running around shortly.

    And… anyone who is in mid-40s and didn’t spend time building and racing RDs or RZs has some explaining to do.

    Yes, I can make a fair set of pipes when I need to


    but I know it can always be better, so I’m not going to get too cocky.

    This comments board isn’t so we can get into a pissing match over who has more credentials… is it?

  • Marcus
  • conceptualize 传奇私服, In reality, I only was about half a mile from <a

  • Marcus

    Well………………………………… Where are they????????

    Well………………. end of 2010 now, where the fuck are they?
    Who has got a RS500GP?
    Who has a completed motor delivered?
    Where is the test of the 1100cc two-stroke Zx10r? All piss and thunder about that then nothing!!!

    This is behond belief

    TSS are so full of shit.

    Other manufacturers deliver. They just wank.

    Talk about a golden oportunity wasted!!!!


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