Yamaha created the maxi-scooter class with its parallel twin 500cc Yamaha T-Max back in 2001 and now it's set to do battle with a new generation of even bigger machines with a monstrous 750cc three-cylinder evolution of the concept.
A whole raft of detailed patent applications for the new bike's design where published early in March, covering the engine and gearbox in particular, revealing intricate details of the new machine.
At its heart lies an all-new engine, taking the basic dimensions of the 500cc Yamaha T-Max twin as a starting point to ensure the new machine is physically no bigger than its predecessor but containing entirely new architecture inside, along with a new CVT transmission designed to cope with the additional power. Given that the Yamaha T-Max already makes 33kW from 500cc, 50kW or more should be within easy reach for the new 750cc engine.
Drawing of the new engine reveal the machine keeps a similar bore and stroke ratio to that of the Yamaha T-Max 500cc, giving a relatively low-revving, torquey engine thanks to its under-square design with a 73mm stroke and 66mm bore giving a capacity of 749cc. Although the crankshaft design reveals an even-firing 240 degree interval between the three pistons, Yamaha has also added a balance shaft.
The top end features a conventional four-valve-per-cylinder, DOHC head, with chain-driven camshaft, but at the gearbox end of the drivetrain Yamaha has gone to some lengths to ensure its twist-and-go transmission can cope with the bigger engine's power.
The drawings clearly feature a conventional clutch rather than a centrifugal design, using electronically controlled hydraulics to activate it.
Yamaha already has plenty of experience with such set-ups thanks to the semi-automatic Yamaha FJR1300, and since the new scooter retains a belt-driven CVT gearbox rather than a electronically controlled manual, the clutch is only needed to take off.
The CVT box itself features metal drive belt technology, stronger than rubber-belt systems and able to transmit twice the power for the same size of pully thanks to the fact power is pushed through the belt, made up of steel plates mounted on a multi-layered metal strip, as well as being pulled through it.
With the current two-cylinder Yamaha T-Max still proving a success for an otherwise beleaguered Yamaha, th three-cylinder 750cc derivative promises to have an even greater appeal to real riders who want scooter practicality.