RCE spares no expense in manufacturing for you the highest quality exhaust system on the market. We fabricate the header flange out of billet steel. This insures that exhaust gases will be properly sealed throughout the life of your pipe. Some of our competitors prefer to use cheap tubing here. If you own one of these pipes, take it off sometime and feel the inside surface of the flange. You will find that the metal sealing band that Honda uses cuts into the soft metal tubing. This will create exhaust gas leakage and power loss. We have seen a 3hp loss on our dyno due to improper sealing at the header flange! Furthermore, every pipe is TIG welded throughout for superior strength and great looks. At RCE, we prefer to make a little less money on each pipe, and add in the performance and safety features that our customers demand. RCE uses the latest in Computer Aided Design technology to monitor curvature down the length of each pipe. This ensures optimal gas flow and the highest quality stampings. The colors in this CAD rendering correlate to degree of curvature. RCE uses several metrics when evaluating engine performance. A very powerful tool in doing so is the calculation of Useable Horsepower. This technique, pioneered by RCE, uses a computer algorithm to automatically find the greatest area under the horsepower curve for a given RPM range. The computer then uses this area to derive Useable Horsepower. Comparing Useable Horsepower to peak horsepower shows how broad the engine’s power delivery is. For example, if Usable Horsepower equaled peak horsepower then the power curve would be flat through the RPM range (the ideal case). At RCE we are constantly trying to find ways to create better information both on the dyno and on the track. Of course, the end goal is to deliver to you a superior product. For 125cc shifter kart racing, we have had the best luck with the 38mm Keihin PWM carb. The PWK has a longer intake tract, which is useful for tight sprint track applications. Jetting ranges are 170-185 for a properly installed 38mm PWM Keihin. This can vary significantly if you have an improperly set float height or fuel pump installation. If using a RS125 intake boot, the intake tract length will be shorter, requiring a slightly smaller jet (1-2 sizes) as compared to the longer stock CR125 intake. Especially for tracks over 1 mile in length, always start on the rich, conservative side of the jetting range. If your engine requires a jet significantly outside of this range, another problem is probably causing it, such as a cracked reed or vacuum leak.