whats with the axle nuts?



ok i have a 2006 se blaster and whenever i come back from riding my axle nut (the one on the left) is lose. i put it back to normal when i get back but can someone tell me how to fix this? thanks.
How To Protect The Axle Locking Nuts

This tip is a labor saving tip. After you have just installed new rear axle bearings,tape up the threads and the locking nuts used to hold everything in place (see illustration below). Use a special heat shrink tape you can buy at any electronics store. Apply it after assembly while the threads are CLEAN, and when you heat it up it shrinks and seals the threads so they won't get rusty, dirty, or damaged. This will enable you to easily loosen the locking nut the next time you need to remove the rear axle. The cost of the tape ($5.00) will easily offset the amount of work and possibly money it will save you. I have seen cases where the threads on the axle got so messed up and rusted from not being protected the lock nut had to be cut off and replaced.