The new Yamaha Star VMax is about to get introduced to dealers in North America in Fall of this year. There has been much speculation about its technical specifications and details. This article focuses on the all new Otodama engine - the code name for the all mighty beast that will be the heart of the New 2008/2009 Star VMax.
It is believed to come with 1800cc in the V4 configurations known from the first generation Vmax. Thats however where all similarities end. The Otodama engine should be capable of producing up to 210bhp from its 4 x 450cc pistons. 1800cc is about 110ci for those of you comparing it to other power cruisers. Thats also as much as you want to compared it to anything else. The new Vmax is about to redefine the definition of Power.
So lets look a little deeper into the all new engine: Of course the new powerplant comes fuel injected. Todays emissions requirements as well as the ability to produce more power at much high efficiencies pretty much dictates fuel injection. A positive side effect of fuel injection is its capability to have larger throttle bodies and wider intake tracts than an carburated engine. Thats what Vboost basically did at high rpms. So with it being fuel injected, there wont be a traditional vboost that opens up the intakes beyond low rpm settings. The yamaha engineers came up with a different way to help the fuel injected engine broaden its power band. In other words create lots of torque down low but also lots of power up high in the rpm range. In order to do that they came up with a variable cam timing system, similar to variable valve timing found in todays high tech cars. It is not as sophisticated as a bimmer valvetronic but allows the engine management or ECU to adjust the valve timing by 20 degrees.
The cam advance is either on or off and is like having two different set of cams, one for lower rpm and another one for high rpms.
So how does it work?
The cams of the new Otodama engine are chain driven. A control chain drives the intake cams of each cylinder bank and the exhaust cams are gear driven from the intake cams. Its pretty much a typical overhead dual cam design with a little twist. The gears that drive the cams can rotate by 20 degrees and are controlled by internal oil channels. Oil pressure sent to either side of the gears, advances or retards cam timing by the same 20 degrees.
It is pretty much an on/off design, similar to the good old vboost that used to kick in at 6000 rpm.
It only takes two additional oil channels and a solenoid on top of each cylinder bank to control. It also makes it a lot easier to control for a rather small and lightweight ECU as part of the bikes design.
This engine will make the Next Generation Yamaha Star Vmax (2008/2009) most likely the fastest production street bike every built. Expect to see 9s-ish out of the gate and possible 8s runs with simple mods.
Interested in more detailed news about the Next Generation Yamaha Star VMax that is scheduled to arrive at dealers in 2008?
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Category: V-Max News
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