the batteries on yfz's for sum reason have a hard time keeping a charge idk why.

 

This is according to some one i heard from the dealer...

When your just running your YFZ450 the battery does not charge. It will maintain the charge. To fix this you need to run with your lights on. This will keep your battery charged to full capicity.

Now i've had personal experience with the YFZ Battery, it died out on us about the 3nd weekend we were at the dunes. Now that we've started running our lights on (high) the whole time i have no more battery issues.

 

i put a CBR600 bat n run wit my lights on n i HAVE NEVER HAD A PROBLEM
i blew the stocker a while ago

get a cbr600 batt

 

I ride at the dunes, and constantly have my RPMs on the upper end.
I have yet to have a prob with the battery, but time will tell.