Botaferro:
I'm really into Muay Thai kickboxing in addition to riding. Pick what you really like the most and give it most of your energy.
Don't ever quit boxing bro. Seriously, boxing is an awesome workout and comes in handy if you have to take care of business!!!
If you race, you need to plan your boxing around your riding. Always think about recovery.
When you are really smoked from riding, you will really feel it in your legs when doing bagwork.
Doing light bagwork will still do wonders for your fighting skills, so if you have to drop heavy boxing workouts, don't worry too much about it, just do a heavy session once a week or so when you feel like it.
When it comes to throwing punches, it is better to give than recieve!!!
Good luck!!!