How To Break In Your Engine ForMore Power & Less Wear !

One of the most critical parts of the engine building process is the break in!!No matter how well an engine is assembled, it's final power output is all up to you !!

Although the examples shown here are motorcycle engines, these principlesapply to all 4 stroke engines:

Street or Race Motorcycles, Cars, Snowmobiles, Airplanes & yes ...even Lawn Mowers !!
(regardless of brand, cooling type, or number of cylinders.)

These same break in techniques apply to both steel cylinders andNikasil, as well as the ceramic.composite cylinders that Yamaha uses in it's motorcycles and snowmobiles.

What's The Best Way To Break-InA New Engine ??

The Short Answer: Run it Hard!

Why ??

Nowadays, the piston ring seal is really what the break in process is all about. Contrary to popular belief, piston rings don't seal the combustion pressure by spring tension. Ring tension is necessary only to "scrape" the oil to prevent it from entering the combustion chamber.

If you think about it, the ring exerts maybe 5-10 lbs of spring tension against the cylinder wall ...
How can such a small amount of spring tension seal against thousands of
PSI (Pounds Per Square Inch) ofcombustion pressure ?? Of course it can't.

How Do Rings Seal Against Tremendous Combustion Pressure ??

From the actual Gas pressure itself !! It passes over the top of the ring, and gets behind it to force it outward against the cylinder wall. The problem is that new rings are far from perfect and they must be worn in quite a bit in order to completely seal all the way around the bore. If the gas pressure is strong enough during the engine's first miles of operation (open that throttle !!!), then the entire ring will wear intothecylinder surface, to seal the combustion pressure as well as possible.