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I have a brand new battery, charged correctly. I have a 1981 kz1100. Does it have an alternator? Im not very experienced with the mechanics of the bike. Maybe its a fuse that is blown? The battery wont stay charged after several starts.

njk031 wrote:

I have a brand new battery, charged correctly. I have a 1981 kz1100. Does it have an alternator? Im not very experienced with the mechanics of the bike. Maybe its a fuse that is blown? The battery wont stay charged after several starts.

It has an alternator that puts out 3-phase AC voltage and feeds to a rectfier bridge to convert it to DC. There is a solid-state regulator that adjusts the ON time of the rectifiers to hold the system voltage at 14V and keep the battery charged.

If the battery isn't charging, it could be the alternator, rectifier, regulator or associated connections. You need a manual with a wiring diagram,

You need to buy or find a meter and a manual. On the older kz's you fire it up set the rpms to 3500 (if I remember right) and check the voltage at the battery. It should read 14 to 16 (again I think). Check all of the grounds and connections. If all connections are good check the regulator first. It might have a different set up being that it is an 81, but it's all kinda the same.

njk031 wrote:

I have a brand new battery, charged correctly. I have a 1981 kz1100. Does it have an alternator? Im not very experienced with the mechanics of the bike. Maybe its a fuse that is blown? The battery wont stay charged after several starts.

If it's like most, there is no fuse between the output of the alternator/regulator and the + battery terminal. The fuses are all in the load lines to the various lights and accessories.

I would so check the connections and grounds first.

thanks for all the advice. Does anyone know where I can get a diagram of the bike and its components. I dont even know where the regulator or the alternator are located.

njk031 wrote:

thanks for all the advice. Does anyone know where I can get a diagram of the bike and its components. I dont even know where the regulator or the alternator are located.

You need a shop manual. Here's one on ebay.