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Evolution Motor

The Mega-Sphere™ for Evolution Engines

The Mega-Sphere™ is a dual squish head and piston design from Dave Mackie Engineering (DME).  The DME 30° piston is made using only the best premium forgings.  It is a 30° full dome piston that is dished in the center.  The piston dish and the shape of the head combine to form a near spherical combustion chamber at top dead center.  The dual squish band is created by machining the stock flat squish area of the head to an angle slightly greater than 30°.  This forms a megaphone or wedge shaped squish area.  This Mega-Sphere™ design forces the fuel/air mixture up into the sphere and toward the spark plug rather than forcing some mixture inward and the rest sideways or outward to the cylinder wall like a flat/parallel squish area does.  The result is the most efficient combustion chamber for complete burning of the fuel/air mixture which means maximum power and economy.  Frequently customers tell us that their fuel mileage is actually better than stock.

The heart of the package is DME headwork, which for decades has been ranked with the absolute best in the industry.  Headwork is porting, polishing, contouring, flowing, competition valve job, and assembly using all premium parts including a titanium collar high performance spring kit.

Cylinder work at DME is done with state of the art air float boring, and automatic diamond honing equipment using current state of the art techniques.  The cylinders, complete with gaskets, are torqued between specially designed torque plates to simulate engine operating conditions.  This procedure allows the cylinders to take the set they will have when installed on the engine.  They are given a multi-level cross hatch pattern that is best for the application and finished off with the latest plateau honing techniques as  recommended by ring and piston manufacturers.

The final part in this potent DME package is usually a DM580 camshaft.  The lift of .580 is enough to extract the tremendous flow and velocity potential of the heads with little or no valve train noise.  The event timing and overlap characteristics make this cam a torque animal from just off idle.  It pulls like a freight train all the way past 6000 RPM.  The result of this DME combination is a very powerful bike with the best overall blend of torque and horsepower available.  Power is usually in the 85-95+ horsepower range with 85-95+ pounds of torque.  The actual power you realize will depend on the total combination you put together.  Carburetion/injection, ignition, exhaust system, and how well the bike is tuned will all have an effect on power output.  DME offers other cam sets ranging from .500 to .635+ lift and we will be happy to work with you to select the best choice for your application.

****The package includes complete headwork using: all premium parts; boring and honing cylinders; pistons, wrist pins, clips, rings; and DM580 or other cam set.



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Some parts and services may not be legal on 1978 and later emission-controlled vehicles. Check your local, state and federal laws.*
*Dave Mackie Engineering high-performance headwork and camshafts are not legal in the state of California for use on 1978 and later emission-controlled vehicles.