rpm

I bought the RPM Dominator II axle on eBay. I know the full lifetime warranty is non-transferable, but is it still worth registering the serial number? If so, how do I enter this in? Has anyone else ran into this issue?

i just thought of putting a tachometer on the kfx... maybe one off a yamaha R6 or something? i think that would look pretty sick. anybody ever see this done or do it themselves? i could probly find one for like 20 bucks locally. it would be cool to see exactly how fast you're going and what RPM...