This is what I have been working on in my spare time. I think it is going alright. I still have to do:
The brakes can’t be locked up at the moment, they always give a little so you can’t for example lean on the front wheel and hold the brakes and expect to stay in the same place.
Create the level editor, at the moment the level is just a bunch of sin waves added together.
Add a little bit of parallax scrolling to add a bit of interest and depth.
Create better artwork for example shocks and rider.
Add dynamic bike bits such as suspension that compresses and a rider that leans forwards and backwards and has a weight (At the moment I fake weight transfer by just rotating the bike).

Library source
Game source