unfortunatly my bike is kept in a storage unit without power, thats why charging on the go would be cool. what about putting a voltage regulator/rectifier inline from the car battery? Or just a 1.5 amp fuse to regulate the consumption of the bike battery?
This method won't charge your battery either as the 1.5 amp fuse will just blow if the battery needs a charge and then you will still have a dead battery. PBDBlue has the correct method listed above. You seem to have hit the stage of dirt biking where you need spend a little more to enjoy your bike. The above method is a very reasonably priced solution that gives you good flexibility to charge the battery anywhere you like. If the battery keeps going dead it is likely time for a new more cared for battery as the old battery may be overloading the bikes charging system. My .02 -- WR Dave.