TECH SECRETS
TRIUMPH’S MOTO2 BIKE STRIPPED
Next year Triumph will take over from Honda as engine supplier for Moto2, MotoGP’s feeder class. The UK firm are using a motor based on their Street Triple 765 powerplant, which has been tested over the last year in a highly-modified Daytona 765 chassis. We spoke to Steve Sargent, Triumph’s Chief Product Officer, about its development. “We needed to get more power and more torque and this was done by increasing the revs and reducing inertia. A standard 765 makes about 123bhp and we’re pushing this to 135bhp and about 59ftlb. A lot of this comes from the cylinder head. We’ve worked with the ports to increase gas flow and put in lighter titanium valves and race valve springs to reduce flutter at high rpm. “The other way to reduce inertia is to do some simple things like removing the starter motor and the starter gears. It also has a race-kit alternator as the race bike has much less demand for electrical power and a lighter, fully-adjustable slipper clutch. “We’ve also changed the gearbox ratios. The first and second that you use on a road bike aren’t appropriate for racing; they’re both taller now and bring the rest of the ratios closer together. “We’ve got a different sump so that the headers can pass through on the other side.” Moto2 convention is that the exhausts exit on the left-hand side of the bike for two reasons, firstly more ground clearance on predominantly right-hand circuits and less damage if a bike crashes on those right-handers. “Another new casting is the right-hand crankcase and clutch cover. This has a separate cover for the clutch, allowing teams easier access. We wanted the slipper clutch to be tunable and this allows the teams to get in there easily.
“We’re running standard rods, standard cams, standard pistons and a standard crank. All of these parts are good enough for the higher sustained rpm and mean that the engine is affordable. “The motors will be built and maintained by ExternPro. They are the company that build all the Honda Moto2 motors. We will ship them a kit of parts for each engine, they build it up, dyno test it and hand it to the teams. Each will do three weekends of racing before it’s rebuilt.”