Riding my bike....and it dies. Help?

[Morrider]

Ok, i pulled and replaced the plug, checked the hoses(they all seemed in good condition), put everything back together, and double checking everything to make sure it was in order. Now, I try and start the bike and the battery is dead. I've had this problem a few times before and have replaced the battery less than a year ago. Before when it happened I charged the battery using a charger specifically for bikes, and that seemed to keep the battery alive for a while. I'll try and get a hold of the charger I used last time, but does it sound like something else might be the cause of the loss of charge so quickly?