So, I am having the same problem with my bike, 72 CB750. The first month I had it 9april 2006) the the battery was lasting. I took it for a ride a week and a half ago and it died at a stop light by my house (I was lucky I was as close as I was). I charged the Batt over night and took it out the next day and it drained after an hour of riding. Lucky for me I felt the change in the engine and turned off the headlight and that gave me enough juice to get home. I could definiutely feel a change in the engine when I turned off the light. So, when I got back home I cut it off and let it sit for a minute or 2. I then kicked the engine to get it started again (no lights on) gave it a few revs the turned in the headlight and the engine stalled and died.
So, I've noticed that my headlight is draining my battery even when I am riding my bike (above 3k rpm). Can someone tell me where to start my trouble shooting? Should I have the batt checked first? It's a now a 2 month old wal-mart battery aka Never-Start, by a local motorcycle dealer.
a little history:
I bought the bike from I guy up in connecticut (over ebay). He has actually been very helpful so I have no reason to believe he was unloading a junk bike to me. The CB750 had been sitting in storage since Nov 2005 and sold to me April 2006. He said the only thing I would need is a new battery and an oil change. According to him it would get a tune up every year and a new battery. So, when I got the bike back home I purchased a new battery at Wal-Mart and filled it up. I did not do the initial charge, (a friend who was helping me said I would not have to worry about it).
In the mean time I was getting ready to pull the old battery out and figured "Hell, I check to see if the old battery still has a charge" so I flicked the lights and turn signals and they worked, to my surprise, I thoght the battery would be drained/dead from sittning. The only thing electrical that didn't was the horn (i just needed a new one). I didn't try to start the bike. So I changed the battery anyway and it worked well for about a month.
I am a new rider, so the first month or so I kept the revs kinda low and just putterd around the neighborhood. So a week and a half ago I start feeling a little more confident in my riding. I wake up early on Saturday morning to beat any traffic in the area. I get to the stop light 250 yards away, down hill (a BIG hill) and then putter, putter, putter, silence (luckily at a stop light). I shut off all the electrics kick, kick, kick, wait 2mins, Kick, Kick Vroooom. Clutch, first, a little gas, a little off the clutch, Dead again. Kick kick. nothing. let it sit and tried again and nothing. I left it there for a few hours and came back and nothing happened (I would have pushed it home but like I mentioned before it's a BIG hill). It just wouldn't start. Then I noticed that when I would try to sart the bike w/ the headlight on the the idiot lights were barley visible. So, I ficked to light on and off to see how much the difference was in brightness. It would go between somewhat visible and barely visible. So I took the batt out gave it a quick charge came back reinstalled it and the bike started right away. I got it home as quick as I could and charged the battery.
The next day, Feeling confident that everything was okay I took it out the next afternoon. Everything seemed fine lights on, signals working, horn beeping, me riding through Rock Creek Park. All of the sudden i could feel a change in the way the engine reacted to throttling and and changes in idle at stops. At stops I would give more throttle to keep the idle from dipping to low. At acceleration, if i would turn the thottle quickly it would putter a little then it would start to pick up, If i did it slowly it would get up fine. Next I turned the lights off and turned the throttle quickly and it was fine. So, I tried it with the light on again and the putter came back. I got a block from my house, off throttle, clutch in, down to second, slowly release clutch, dead to a rolling stop. I swear I didn't stall it. It felt like the bike just died. It was not violent like a, I don't know how to use a clutch, stall. Everything just died. So, I turned the headight off gave it a kick and it started. I went one block, headlight off at dusk and parked it in front of my house safely. Just to check it I started it up then turned on the headlight and the bike died.
any Ideas on where to start? I have the clymers manual and can't figure on a starting point. I would like to fix it myself if possible. but if I have to take it to a shop, then I will.
I have also looked and posted the same info on this thread as well. After reading it, it sounded like I had a similar problem
http://www.sohc4.us/forums/index.php?topic=5613.0