Originally Posted by
cesspool
what's the difference though bewteeen a non race and and a sport?
Well, the sport would be considered an RTR engine or a basher engine. Where as the R is built for racing. It probably makes more HP, has a composite carb and I don't know what else. I just know for a 'sport' engine, the normal 3 port is PLENTY.. at least for my small track.
As for your earlier question about carb inserts and traction.. Carb inserts would help with traction by limiting the power. Its just a piece of plastic that sits inside your carb throat and they usually come in sizes of 6 - 8 mm. They also improve fuel economy.