Framecrafters Trackmaster style frames are based on an original FC has. We have made some minor modifications to over come some inherent flaws in the original. (ig.the swing arm pivot is "boxed-in" not plated) We have seen these frames raced in both dirt track and road racing to much success. Most unit-construction twins and singles will fit in this design. Some pre-unit engines will fit in our long version. This frame is available with a round or box section style swing-arm. Tapered roller bearings come with for the head-set and bronze bushings or needle bearings are available for the swing-arm. The frame pictured shows no motor mounts,upper shock mounts or seat\tank mounts. Depending on the final application, that will dictate were those last items are mounted. Most aftermarket seats and fuel tanks for our t-master will fit. Alloy oil tanks and OIF is available too.