Can riding without a chain damage a bike? I've been really struggling learning to ride fakie (backwards) on my BMX. Tonight, an idea occurred to me. If I remove the chain from my bike, it'll be a "free coaster," and I won't have to pedal backwards while riding backwards, so I can focus entirely on balance and maintaining speed. I don't know if removing the chain would actually be very helpful, though I'm sure it would be fun and I'd learn some things. Is there any chance it would be harmful to the bike?
What harm could it possibly do? The cranks are held firmly in place by the bottom bracket; the back wheel is held firmly in place in the drop-outs. The chain is completely non-structural: all it does is transmit power from the pedals to the rear wheel.

The only issues I can think of are


make sure you know how to remove and replace it, obviously;
I pretty much guarantee that you'll fall off at least once because of this. You know, as an intrinsic part of riding a bike, that putting forward pressure on the pedals has various effects and you use those effects subconsciously to control the bike. Now you're riding a bike where putting forward pressure on the pedals just spins them with no resistance. But, hey, you're practising tricks so I assume that falling off isn't a deal-breaker. :-)


Benedikt Mokroß adds


You're going to hit your knee on your stem a lot. Been there, done that.