Now that the dust has settled on the new blow-down rule, I would like to further explain to everyone, the reason we felt a change was needed. A few years ago, the USPKS/Route 66 Series implemented a blow-down rule, and after talking with some engine builders, we chose a minimum of 0.380” as a starting point. Since that time, we have been tracking engine blow-down and conducting more research, while continuing to work with the industry engine builders.

Based on our research, (and confirmed by most of the engine builders) we have learned that most, if not all, the engines coming from Yamaha are 0.390” plus. This means that anything that is just over 0.380”, more than likely has been altered from its original casting, which is a direct violation of the long standing technical regulations, accepted Nationwide. The cast part of the Yamaha cylinder is to remain “as cast”, which means that removing part of the casting to improve the performance is illegal.

The Yamaha is a mass produced cast cylinder, so you will have some cylinders that are better than others. Altering the cylinders to improve the performance, then hiding it, is something that has been done, at considerable expense, to gain an unfair advantage. We have implemented this rule to help level the playing field again, because this will eliminate the cylinders that have been altered, and close the gap between the average cylinders and the best cylinders. We have the backing of the majority of the US engine builders on this change, because they want to be on a level playing field also.

We know we may face criticism from some people, but doing what is “right” isn’t always popular. Engine builders and racers asked us to even the playing field by eliminating the advantage gained by expensive illegal modification, because it was the right thing to do. Our intent is to make this as level of a playing field as we can, so the people running at the club level can come out and try their luck at a regional race and not get their butt handed to them by an illegal engine.

We are in this sport because we love it, and we want people to have a good time when racing with us. If you are not even close to being competitive, you‘re not going to have fun, and sooner or later you will move on. The USPKS/Route 66 Team is in this for the long haul, and we continue to be an industry leader, which sometimes makes us vulnerable to criticism, but in the end, we hope to make karting better for everyone. The sport just needed someone to take the first step and this organization is willing to do that.

Thank you and see you at the races!

Rick Jump
United States Pro Kart Series
Route 66 Sprint Series