its matched to 907cc pistons + carrillo rods.
Weight reduction DOES NOT provide more power. hp and torque are NOT increased at all.
All weight reduction does is allow the engine to spool up faster.. Best example is this.
in neutral, at idle, slam the throttle open, measure the time it takes to hit the rev limiter. That time is now reduced because you engine can spend less energy trying to rotate that hunk of metal around.
@ hansj
balance shafts are to offset pistons and rods. yes they have to be touched slightly, but its VERY minimal. its possible to leave them alone in my case. (but when would i ever leave anything alone ?
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Rotating mass is they key to making a bike produce "power". And by power i mean "be efficient".
The more weight you can pull out of rotating pieces, the more your engine can transfer to the wheel, faster.
MotoGP bikes are inherently clever in this area. Look at Rossi's rear sprocket, and compare it to your own. Have a look at how much weight he cuts out. Now think of EVERY rotating part in your engine. gearbox gears, shafts, even your front sprocket. Everything can be lightened. At the cost of durability / life.
The more material you take off something, the weaker you make it. The less life it has. Obviously cranks will last a fair while, but sprockets, gears, primary / secondary gear shafts, etc.. the more you take out, the less they last. MotoGP has a HUGE budget (40mil AUD a year, so says a certain head engineer who lives nearish to me).
Sprockets / gears are replaced every race. They last a weekend, then sent off for X-Ray testing. If they come back perfect, the specific engineer says "well, they haven't started to fatigue yet, so theres some material that can be removed." They literally WANT them to come back with hair line fractures between every tooth on the gear. So they know the limits.
Remember last season (2007) philip island, rossi's motor basically blew up ? They cut out soooo much weight to get power to the ground faster, at the cost of ruining his bottom end. And the fact that he was possibly experimenting with direct injection (which fiat did.. 5 years ago ? now the ferarri enzo (which fiat own) now utilises DI..?.. do the maths people)
Given that they use X octane fuel, they have a limit of 19,000rpm, are 800cc, the physical limits (well, as far as current know physics are concerned) they can only produce Xhp.. So they experiment on removing load.
Pneumatic valves. They already have crank case positive air pressure. Why not utilise that for a valve return ? instead of springs. Less load on the cam to push the valve open. etc.. (desmo valve anyone ?)
All i am doing with my spare engine is changing a few key things about it. Variable spark control, fuel injection, lightened crank / pistons.
Last thing i have to do, in the "major" mod department is off-set the barrels by 2degs. Basically, where the barrels bolt to the upper crank case housing, im going to make the barrels tilt slightly.. Anyone have a guess why ?
(and im welcome for anyone to show me im a total moron and dont need to, im prepared to read / learn pros and cons on anything here. So please help me !! this engine is a pure experiment..)
..was sorta gettin there with the piston angle. Much the same as changing the length on a horn loaded pa box.
