Cardio Heart Exploder

I got this thing moving in a circle on Saturday (grass field) and soon my heart was pounding like a speed-metal band bass riff . . . I think I need some cardio training ?  The motor's still kinda puffin' out the pipes, and now it don't want to come down off mid-throttle again????  A couple weird little glitches.  I'll figure it out - but hey, it's fun to ride and has a great sound !

 . . .  and it just looks cool.