My exhaust pipes use proven racing technology 1-3/4" diameter pipes. The stock Yamaha pipes were only 1.15" ID. My pipes improve flow by about 200% over stock for increased top end horsepower. The XtremeXhaust Optimizer™ kit fattens out the power band with a bunch more power and torque over the entire useable RPM band but the biggest gains are in mid and low range.

Exhaust Port Optimizer

These EPO inserts fit between the head and exhaust pipe. The sleeved portion of the insert reaches into the port and "fools" the exhaust port into improving valve flow. It also reduces cylinder head heat retention by filling the back-pressure gap (black area) previously filled by narrow stock pipe. A cooler head and hotter exhaust gases make more power. After an exhaust valve opens, the exhaust pressure wave rushes down the pipe, hits the end of the pipe, then turns right around and pulses back toward the cylinder. These narrow diameter port inserts minimize some of that reversion wave in anticipation of the next outward wave. This improves low and mid range carburetion efficiency. You will find carb tuning for maximum output is much more precise. This insert works wonders with stock engines but it is highly effective with tight lobe center acceleration cams in high performance engines. They "bolt-in" as you tighten pipe flange.

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