Description
Stock rear sprockets are built to a budget, not a lap time, which is why so many racers swap theirs out before the first tooth even shows real wear. ProTaper built its Race Spec (RS) rear sprockets around a CNC-machined Angled Mud Groove that channels debris away from the tooth roots as the wheel spins, instead of letting it pack in and wear a groove into the chain. This blue 51-tooth rear sprocket is machined for Honda and Yamaha off-road models, and the groove layout also opens up roughly 40 percent more tooth surface area than a standard flat-plate design, so the chain rides on more material with every link that engages.
What makes this sprocket worth the swap:
- Angled Mud Groove design self-cleans during operation, shedding packed mud and dirt instead of trapping it against the chain
- CNC-machined tooth profile increases contact surface area versus flat competitor designs, which spreads load and slows wear
- Countersunk bolt holes self-center the sprocket onto the hub during installation, so no separate hub center guide tool is needed
- 51-tooth count for Honda and Yamaha off-road models, sold individually and ready to bolt on with stock hardware
- The blue anodized finish is a common pairing on Yamaha-blue builds and resists fading better than paint, so it still looks sharp after a season of mud and pressure-washer abuse.
Running a 51T rear tightens acceleration through each gear, useful for tracks with tighter turns or riders who want the bike to snap up out of ruts instead of lugging. It fits the same hub as the stock sprocket it replaces, so the swap is a straightforward afternoon job for anyone comfortable pulling a rear wheel.
