I just purchased my first street bike a 2001 Ducati Monster 750, 4000K. The bike ran fine, rode it for about 50 miles, then I think I left my light on cause it wouldn't start, no lights. I tried jump starting it with a honda civic that was off, wouldn't start so I turned the car on, bike still wouldn't start.(I know I'm an idiot, but now I'm alittle smarter, I will never do that agian). Took the battery out, charged it overnight, put it back in, still doesn't start. Figured out it was the 30 amp master fuse. Wahla, bike starts. I'm off. 5 more miles bike dies mid flight won't start. I figure the battery won't keep charge, its original battery 8years old, so I buy a new battery. New battery, bike runs great agian. 5 more miles, bike dies. Then I find this big blown 40amp fuse near the battery, it's blown, but bike still starts. I replace the 40amp fuse, charge battery bike runs agian. Now I decide to test if the battery is being charged. It shows 12.3v idle, 13.6v with constant rev. So I take the bike out thinking I fixed my problem, the tach starts going wacky and stops working, when the tach did work the bike got its power back. Now the tach doesn't work and the bike doesn't have the power it used to and lights seem dimmer. Its like theres not enough electric to run the bike. I hope you guys can help, I want to ride this bike a lot. Thank you.
Sounds like it's not charging.
13.6 is kinda low for our bikes
Could be a bad regulator /rectifier or a bad connection from the alternator.
Kinda odd it keeps blowing fuses.
Start with the simple stuff...battery connections and the connector on the wires that run from the left side case.
Thank you very much for the direction. I don't think it keeps blowing fuses, I think I blew the master fuse under the seat and the 40amp one near the battery when I tried jumping it. I didn't know about the 40amp fuse until after I bought the new battery and the battery died because it wasn't charging cause the 40amp fuse was still blown. Now that both fuses are fixed the battery seems to be charging and the bike starts fine, it's just not running at full power, lights seem dimmer and tach doesn't work. It was intermtintly getting power and tach but now I don't get the tach or the power. Maybe I'll buy an a regulator that seems easy enough to replace....
Quote from: SeaLander on May 12, 2009, 07:35:44 PM
Thank you very much for the direction. I don't think it keeps blowing fuses, I think I blew the master fuse under the seat and the 40amp one near the battery when I tried jumping it. I didn't know about the 40amp fuse until after I bought the new battery and the battery died because it wasn't charging cause the 40amp fuse was still blown. Now that both fuses are fixed the battery seems to be charging and the bike starts fine, it's just not running at full power, lights seem dimmer and tach doesn't work. It was intermtintly getting power and tach but now I don't get the tach or the power. Maybe I'll buy an a regulator that seems easy enough to replace....
Gotcha...
Before you buy stuff....
Check to see if both cylinders are firing.
Easiest way is to check if both headers are hot...and I mean they get hot...be careful.
If they're not I'm thinking bad thoughts.
I found this:
http://www.ducati.ms/forums/showthread.php?t=6288 (http://www.ducati.ms/forums/showthread.php?t=6288)
So I determined that the 2001 750M has a 3 phase charging system. I tried to see if the yellow wire was the problem. I followed a bunch of wires, wiggled them, etc, looking for bad connections. The yellow wire connector looked fine. I also read somewhere that disconnecting the battery resets something in tach or something, maybe it was in my head, so I did that. Walah.. tach was working agian, bike sounded normal agian, light were normal. Rechecked the charging system agian. 12.3v off, 12.5v idle, 13.4 at 3k, 13.6 at 5k and it stayed steady. I rode the bike for about 30 minutes and seemed normal. I'm about to go for an 40 mile ride. Hopefully I won't need to get it towed back ... thank you for your support!
I know the problem already. There is a wire on one of the coils that feeds both the tach and one of the cylinders. It constantly worked loose on my 750 and the tach goes out and you lose a cylinder. I believe it is a red wire and it is on the bottom side of the coils. Just check all the wires attached to the coils and make sure they are secure. If they are then follow that wire and make sure all connections feeding it are secure as well.
WOW, right on. The power and tach cut out again. One of the cylinders was cold. After examining the coils I found the gray wire was off, plugged it back in and all is well, again! Awesome, love easy fixes.
Thank you very much!