2006 XTREME MACBOR 510R MX, Pro Quality AMA Legal Youth Motocross 51cc Stock Class Race Bike. Start your aspiring racer with a real race bike. This bike is top quality, on par with the best! All components are premium quality from Spain. You can Buy, Train and Win Races on the MACBOR 510R from XTREME. The 510 R is one of only three 2005 production model Motorcycles approved by the AMA that can realistically win in the class. Meets the rules with no changes! This is not a converted XR 50, JR 50 or PW 50. The MACBOR 510R is a race bike available for the discerning rider at a value price. At least $300 cheaper MSRP than the closest competitors equivalent bike.