Arrrrrrrrrrrrrrrrrrrrrgh!!!!!

I am tearing my hair out now. My bike spent most of last year in the shop with various electrical ailments. I got a new starter and battery last year. Left the battery on a trickle charger all winter and put it in the bike on Tuesday. Rode the bike Tuesday and Saturday. On my way home, the speedometer suddenly dropped to nothing for about 10 minutes, then went back up, then down again later and so on. It never died on me (like last year) and so I stopped at a local bike dealer. He tested the battery and it was run down. We jumped it, but before I got off the lot, it died again. This happened 2 more times. Since it was closing time and I did not feel like pushing the bike 2 miles, I left it there.

So what can it be? An alternator or just bad luck with batteries.
Help!

If you left your battery on a "trickle" charger all winter, you probably cooked it. Trickle chargers are for slow charging of a battery, not constant charging. You need a "maintainence" charger if you want to leave it on all the time.

John, If that bike were mine, I would try some basic troubleshooting techniques. Do you have a manual? If not, get one. I would try the easy things first. I would not SUPPOSE anything as you had problems last year prior to cooking your battery all winter. First, either get the battery load tested at an auto place or bike shop with the necessary equipment or at a minimum buy a very small hydrometer and test the cells. They sell them at autoparts stores and the one you need will cost $3. FIRST you need to know if the battery is capable of holding a charge. If it IS and the battery checks out, then the system that charges the battery will be your next stop in troubleshooting. The battery has two cables and these MUST be secure on both ends. Then look at the connections where your alternator go into the regulator/rectifier connector. Trace the wires from you alternator up till where they plug in. There may be yet another connector between that connection and the regulator/rectifier. Open up both connectors or the single connector and clean the contacts using SPRAY CONTACT CLEANER. They sell it in autoparts stores and sell the same stuff called Tuner Cleaner in RadioShack. After, coat the metal connectors with dielectic grease. Many times, poor charging is just a poor connection. If that doesn't do it, you will need a multimeter and will need to do some measuring. You can make an easy test of your regulator/rectifier by measuring battery voltage with the bike idling. A good reg/rec will show about 12.5VDC at idle and about 14.5VDC at 3500rpm. If your measurements show less or MORE, then the reg/rec is probably not working right and should be changed. If the rec/rec checks out, then you likely have an alternator issue and will need to make measurements on the AC on each of the legs. The manual will definitely be helpful in this case. Go about chasing electrical gremlins in a logical manner and the problems will become a whole lot less complex and more manageable.

Thanks for the assistance everyone. About the trickle charger, I just did what the mechanic I used asked me to.