It sounds like your slipper is too loose, tighten it all the way so the spring is fully compressed and then tighten even harder. Be gentle when you pull out ease into the throttle. Get the plastic gears for the robinson. This will get you through until Mike gets the stobes in. This will almost be like having no slipper so it will most likely not slip and be hard on your drivetrain if you get on it hard or stay on the throttle while landing a jump. But it should be fine for speed runs.
Never fight an ugly man..... he has nothing to loose
I did not see the robinson plastic spurs for there new design. If you know where to get them please let me know. Their slipper is a tower hobbies, here is the link if you want to see it so you can help me.