No electrical power after jumpstarting

Adam970 wrote: I just bought my first bike, a 76 kz400 D3 with a no spark problem, I bought a new coil and when I was testing it, the battery ran out of juice. So i took a car battery jump starter to get the battery going again and the bike was turning over great, however I came back later and now I have no electrical power. I checked the battery and it has about 11.5 volts. I have a multimeter but I have no idea what to check from here. Any help would be appreciated!
-Adam

If after charging the sustained voltage is less than 12/13 volts, the battery is bad. No amps. Could be a short inside or something else. A bad battery can rob the electrical system of the needed power to run the other systems. It can also be intermittent. Working one time, then while riding cause electrical issues, even damage to the charging system. Cheap insurance to have a new battery.
Steve

Ed,
I can go online and find just as many links that say running car, no problem. I'll stand by what the BMW and Kawasaki pro's say in their training classes. Do what you want and I'll do what I want.

80B4 wrote: Ed,
I can go online and find just as many links that say running car, no problem. I'll stand by what the BMW and Kawasaki pro's say in their training classes. Do what you want and I'll do what I want.

I agree. Ed

650ed wrote:

80B4 wrote: Ed,
I can go online and find just as many links that say running car, no problem. I'll stand by what the BMW and Kawasaki pro's say in their training classes. Do what you want and I'll do what I want.

I agree. Ed

What is so difficult about shutting off the jumping vehicle? For safety if nothing else. If the car has to be running to turn over a bike, that battery shouldn't be in service anyway.
Steve

however when you start your car engine then you are delivering considerably more than 12v of power. It is this additional power which can cause damage to the motorcycle.

:laugh: Additional power, err cranking amps ? the system draws just as much as it needs, and no more...jump start of a U boat battery pack if you want, just as long as it is 12 volts.

Type 21 U boat 34,000 Amp hours capacity, Kz bike 8--14 amp hours.
Oversupply of 'power' or more precisely cold cranking current is never a problem, it usually the other way around when the battery is tired and the connectors bad: battery can't supply enough cranking current so voltage drops...hence the ballast resistor approach on some kz.

I've jumped off running motors on bikes and cars for decades, breakdown recovery drivers do it all the time.


OP A badly defective battery will never hold charge and wen really bad acts like a big resistor and just pulls the sytem voltage down. Go through your charging system starting with battery, battery leads and earth straps and check you alternator stator connections etc.

Thanks for all the help everyone. somebody had replaced the inline glass fuse with a block fuse and the 20 amp main fuse had blown.
-Adam