Cylinder/Head Porting

A variety of things can be accomplished through engine porting modifications. Performance can be dramatically improved but this generally comes at the cost of engine reliability and lifespan. Over increasing horsepower can reduce the effective life of a top-end (piston and rings) by more than half. If the pistons in ported machines are run past their reasonable service life horsepower gains will actually reverse themselves rapidly robbing horsepower and the risk of catastrophic piston failure looms like coming up short on a triple. For the serious racer where budget is of no concern and every bit of power counts this would be the logical choice. However, most racers are looking for horsepower improvements that do not increase maintenance costs. Through a more conservative approach, moderate horsepower gains can be achieved while actually increasing reliability without sacrificing top-end life. By using proper techniques you can guarantee your engine runs at it’s full potential through the life of each top end by improving airflow dynamics and reducing horsepower robbing and potentially harmful carbon deposits. You don’t need to be an experienced porting technician to clean up the casting flaws present in most engines (green and yellow 2-stroke engines benefit greatly from this), reshape, as necessary, intake and exhaust passages, and polish head and exhaust components (including 4 stroke valves or 2 stroke exhaust valves). The overall effect is an engine that runs stronger, smoother, and crisper with increased longevity and reliability. For the racer on a budget porting is a wise investment compared to more expensive and more dramatic porting done by other shops that can dramatically decrease the life of your top-end.


4-stroke
Parts needed; cylinder head, valves

Porting procedures for 4-strokes: Casting flaws will be corrected as necessary throughout the head, and irregularities in the exhaust port will be corrected. The dome of the head will be polished and the valves will be polished where applicable (some valves with coatings could be damaged if polished). The overall effect will be an engine that flows smoother than stock and resists carbon deposits. Thus not only improving horsepower initially, but will retain the horsepower gains much longer through the piston life than a stock engine.
To prepare head for porting simply remove it from the engine, remove all extraneous parts such as headers, the valve cover, etc, remove valves from engine and remove the valve guides, then replace the valves in their proper location and secure them (it is very important that you do not mix up the valves or your engine will not run at optimum performance levels).
It is recommended that you start with a fresh top-end to reach full potential and your clutch should be serviced as necessary. Both components are available through Mxmegastore.com.



2-stroke
Parts needed; cylinder, exhaust (power) valve, cylinder head

Porting procedures for 2-strokes: Casting flaws will be corrected in all intake, transfer and exhaust ports (Green and Yellow bikes greatly benefit from this). Airflow dynamics within the cylinder porting will be adjusted for optimum airflow without altering to the point of over-performance (over-performance is when the engine’s horsepower gains are above what the engine components can reasonable handle thus significantly reducing piston life). The head and exhaust valves will be polished and the exhaust port will be reshaped as necessary and polished as well. It is recommended that you increase your main jet at least one size from stock or switch to 50/50 race gas. Start with a fresh spark plug and check sparkplug for proper color after 15 minutes of regular riding. Adjust jetting as needed.
To prepare cylinder and cylinder head for porting simply remove them from the engine, remove all extraneous parts such as the reed cage and exhaust washer. It is recommended that you start with a fresh top-end to reach full potential and your clutch should be serviced as necessary. Both components are available through Mxmegastore.com.