This is the place I will try and detail what I am doing with my pilot. I will eventually have a 2007 yamaha phazer engine installed in my pilot.
Here is an article I snagged about the motor from ATVSport.com
For 2007, Yamaha released a new Phazer snowmobile it calls ?The lightest liquid-cooled sport sled.? The Phazer 500 features an all-new engine that churns out 80 hp from a four-stroke, two-cylinder 498cc fuel injected engine. Does that twin cylinder sound familiar Banshee fans?
But it?s how that engine was developed that has churned the rebirth of the Banshee rumors. The Phazer features the Genesis 80FI engine that is based on the old two-stroke YZ250F dirt bike engine.
?It?s actually two of them engineered together to become a snowmobile engine,? Yamaha says. ?The Genesis 80FI ? with a 5-valve head makes its peak horsepower at 12,000 rpm.? Interestingly, the former Banshee used a GP-motorcycle-derived 347cc two-stroke powerplant.
ATV Sport
A look at the throttle bodies of the Genesis 80FI engine inside the Yamaha Phazer chassis.
The Genesis 80FI actually has the same bore and stroke as the YZ250F at 77 x 53.6mm even though it?s a four-stroke. Compare the Genesis? bore and stroke to the Banshee?s 64 x 54mm and there?s reason to be excited if it did become reality. The engine is die cast and plated cylinders keep the weight down.
Engine Dynamics
Everybody remembers how frustrating the high-revving Banshee could be in loam and deep sand. One could rev the snot out of it and just spin the tires. With the Genesis 80FI on the Phazer, Yamaha employed a gear reduction system to capture the power.
With the engine making its best power at 12,000 rpm ? compared to the Raptor 700R?s 9,000 rpm ? the gear reduction system improves clutching with the reducer in place. Yamaha says the reducer is geared at 35/50.
Another added feature includes the knock control system that protects the engine from detonation due to bad fuel. The 80FI is rated for 91-octane fuel.
A lightweight, counterbalanced crankshaft provides ?super-crisp throttle response and quick acceleration,? Yamaha says. The counterbalanced crank reduces vibration sent through the engine and chassis to the rider that can be present in two-cylinder machines. That would be a welcomed relief from the vibration-happy decades old Banshee. This is a newly designed gear-driven crank. ?The second and third lobes on the crank are designed with a wider channel than the first and fourth to reduce weight,? Yamaha says.
Technology found on this engine is what Banshee owners have been waiting years for: fuel injection, a lightweight four-stroke engine that delivers torque-hungry performance and reduced vibration from a twin cylinder. Lucky for the snowmobilers, they got the technology first. Let's hope the ATV enthusiasts aren't left out!
80 4-stroke fuel sipping fuel injected power in a pilot! Where's my Milwaukee's Best? Because it sure doesn't get any better than this!
From additional research I've found that the peak HP is from 10,500-11,700 with peak torque at 8,800 RPM. With the reduction the driven clutch is turning at 7,350 RPM when the engine is turning 10,500 RPM, and turning 8,190 RPM when the engine is at 11,700 RPM.
To calculate how fast the engine is turning at any given clutch speed divide the clutch speed by 0.7. Or the primary clutch speed can be determined by multiplying the engine RPM by 0.7.
The pilot transmission gear ratio is 9.857:1. Stock tire size is 24"
I will be using a 10-1/2" team driven clutch with the stock yamaha drive clutch which is 8" in diameter. Does anyone have any idea where I should start with driven clutch tuning? I have 4 different helix angles to choose from and 3 different springs on hand. The clutch is packed away right now, but when I get a chance I'll post the angles and the spring weights.
