No, absolutely not. Do not ride. You can't, at this stage, make yourself any fitter by the weekend, but you can certainly trash yourself. You're better off eating and drinking regularly and resting up so your mucle and liver glycogen levels recover fully by Saturday. Maybe, if you feel sharp on Friday go out and do a set of short, sharp, ten-second sprints with around 1 min 50 recovery between them, about ten of them, but no, there's absolutely no point in training now.
Mayhem's all about being able to go hard and recover in two hours or less then doing it all over again btw.
Anyway, rest. There's nothing to be gained from doing anything more than a gentle spin and maybe something short and sharp day before to wake your legs up. In my opinion anyway.
