I dont think it's gonna make a lot of difference what you do now.

The neighbour is annoyed and complained (again), he will be listening for the bike now, and well continue to complain whether its 89db or 99db.

People are predictable, it will now just be a case of "that bloody bike again". So instead dont address the problem with the bike, address the problem with the neighbour, whether that be through mediation, a small placating gift, or a punch in the face.

From my experience a punch to the face won't cut it.

You could offer him a ride on the back of your bike.

If that doesn't work you could always sweet talk his misses.

If that fails keep your entry and exits from home as short as possible.

The gift is also a good idea...carton of Jim and coke drunk together.