1100cc 2-stroke triple Superbike

Imagine the power to weight ratio of what the Superbikes are getting these days. Imagine adding 50% more to that! Imagine no more as there's a bunch of crazy enough people to build a 1100cc 2-stroke engine making more than 250hp.

One for the "Because We Can" file: What do you do when you're bored with the paltry horsepower from a garden-variety Japanese superbike? We've seen power output from the Japanese fours plateau around the 150-hp mark (at the rear wheel on a dyno) for a few years now, and the OEMs seem to be focusing more on rideability rather than the exponential increases in torque and horsepower we've grown accustomed to over the last three decades. If they can make 220 hp MotoGP bikes, they can make them for us. If they wanted to.

Stephen Rothwell of The Two Stroke Shop, located in Tropical North Queensland, Australia, decided to tackle this crisis by using tried-and-true technology: the two-stroke engine. Rothwell had heard enough of legendary two-strokes like the Yamaha TZ750, so he decided to build his own legend. Rothwell and partner Wayne Wright (who designed two-stroke motors for GP race teams in New Zealand) were already building complete top-end kits for Yamaha two-stroke motors, so they already had some of the parts and the know-how for such a project.

"What the world needed was an answer to the current literbikes, which we find anemic," Rothwell told me over the phone. "If a bike can't hoist the wheel in 4th gear off the throttle it's not a superbike." The 1100cc three-cylinder TSS1100GP should have no such problems; when completed, it should make 250 hp at the rear wheel and 160 ft.-lbs. of torque. A powervalve will keep things rideable, with a characteristic hit of power as the revs climb. The chassis will be a lightly-modded Kawasaki ZX-10R ("it's beefy enough") and Rothwell expects the wet weight to be under 340 pounds: "when you dismantle a literbike and see how heavy that four-stroke motor is, it's just sad, really." The next project? The 112-hp TSS500 engine installed in a Yamaha WR450 supermoto chassis. "There's nothing 'super' about a four-stroke supermoto," sniffed Rothwell.

Not crazy enough? Rothwell and Wright can build you a 2200cc four-cylinder that could pump out 500 bhp and 300 ft.-lbs. of torque (add 10% if you want to run alcohol), although he admits that would be "far too much for a motorcycle, even by our standards." But the goal of TSS isn't to crank out demented one-off specials for wealthy lunatics. Rather, it's to bring attention to the efficient, powerful, and even environmentally friendly (Rothwell says these engines could be Euro3 and CARB compliant with the use of direct-injection technology) potential of two-stroke motors. The hope is that the Japanese factories will return to the smokey, wheelie-ing ways of their youth (minus the smoke) and build light, fast and durable motorcycles that can scare the crap out of us.

For more information: click here

A lightbulb moment

Suzuki refines Hayabusa engine

When Suzuki developed the GSX1300R (which was launched in 1999), it set out to build the fastest mass-production motorcycle on the market, complete with a 1,299-cc liquid-cooled in-line 4-cylinder engine capable of producing 156 hp and with a top speed of 189.6 mph. The bike later gained the name "Hayabusa" (Japanese for "Peregrine falcon"), and set the foundation for a horsepower race later joined by many other German, Japanese and Italian bike makers. As competitors gained ground in the power war and regulators passed more stringent emission regulations, Suzuki engineers studied whether to reinvent the 'Busa for 2008 or to improve upon its already formidable foundation. A keen eye on the balance sheet and die-hard fan base quickly led the engineers to understand that rather than starting from a blank page, they'd be better off tweaking the basic engine architecture in order to gain more power and to meet new emissions regulations.

They decided to leave the cylinder bore at 81 mm but to increase the stroke 2 mm to 65 mm, boosting overall displacement to 1,340 cc. Redesigned forged three-ring aluminum-alloy pistons provide weight savings of 1.4 grams each, while the revised shape of the piston crowns, combined with the use of chrome-nitride electro-plated coating, allows an increase in the compression ratio to 12.5:1 from 11.5:1, provides a smoother surface, and increases durability. Connecting rods are chrome-molybdenum steel-alloy and undergo shot peening in order to increase their strength.

Engineers modified the Hayabusa engine's crankcase breather system to include reed valves to prevent pressure waves generated in the airbox from reaching the crankcase itself, thus reducing mechanical losses.

Moving from steel to titanium valves cut the weight of each intake valve by 14.1 grams and each exhaust valve by 11.7 grams. This allowed engineers to increase valve lift to 9 mm versus 8.8 mm on the intake side and 8.6 mm compared to 7.5 mm on the exhaust. The cam chain tensioner is now hydraulically operated, resulting in improved timing accuracy and reduced mechanical noise.

[ILLUSTRATION OMITTED]

In order for Hayabusa's engine to meet the Euro 3 and U.S. Tier II emission requirements and live up to the motorcycle's performance roots, Suzuki developed a digital fuel injection and advanced engine management system, controlled by a 32-bit, 1,024-kb ROM processor. Twin tapered 44-mm double-barrel throttle bodies with two butterfly valves in each barrel help improve combustion efficiency and provide linear throttle response at low- and mid-range torque. Fuel is delivered via two compact fine-spray injectors (each with 12 holes) located in each throttle body barrel--the primary aimed at a 30[degrees] angle down the intake port and the secondary aimed at the secondary throttle valve to add fuel at higher rpms--for improved fuel atomization, combustion efficiency, and fuel economy. The engine management system features an idle speed control that automatically regulates the volume of fresh air fed into the throttle body idle circuit, for improved cold start performance and greater idle stability under changing conditions. The 2008 Hayabusa is expected to produce 179 hp at the rear wheel, and thus continue to set the benchmark for high-performance bikes.

Kevin M. Kelly

As I read this article, it had struck me that the idea I had earlier for reducing the crankcase pressure using a reed valve was exactly what Suzuki engineers used in the new Hayabusa. It now serves as a very good reference on where to start of the project and its likely benefits. Updates on this to come.

2008 Hayabusa Crankshaft

New from APE, racing's premium crankshaft supplier, a new two millimeter stroker kit for '99 thru 07 Suzuki Hayabusas

Kit consist of a brand new 08 Hayabusa crankshaft, but you can't buy this one from Suzuki or anyone else.

Rod journals are fluted for extra oil at the rod bearings

Micro polished

Computer balanced to less than 1/3 gram.
( these cranks don't come from Suzuki balanced that well)
This allows you to run this crank with the counterbalancer removed if you like

Certificate of balance..

Spacer plate, allows this crank to bolt into earlier busas without changing rods or pistons. ( Use 08 main bearings )

When used with a 1397 motor, it yields 1441cc.

These cranks list at $1040.00 from Suzuki

Kit Special from APE $975.00 Outright.

Options include lightening and/or counterbalancer gear removal.

In stock. Phone 661-256-7309

The bike just reach our shores, this is already available for the Generation 1 busas... How nice.. lol

Busa up close and personal (Part 4)

It's been a long while since any updates. The hayabusa has since been out for almost three months already. Here's the next instalment of the overhaul process - The assembly. The cylinder head with all the valves fitted in and the valve covers fitted.
Nice and clean valvesA cleaned up head.
Cleaned up and polished exhaust port. Compare to the before photo.Putting in the race-cut transmissionsPutting in the pistonsFitting up the block

And the rest is all history, now the bike is up and running, stronger and smoother than before... More updates to come on the ride itself.