1975 kz400 parasitic drain

So I bought this bike a couple weeks ago for $300 not running. Put a new starter in it now its all good but it was a sort of half assed cafe racer project so its still pretty rough. I noticed the battery that came with it was dead so I put it on a trickle charger and put it in the next day it was fine, then died overnight. Pulled two batteries out of my other bikes one of which is 100% good and they also both died overnight while in the bike. I taped up all the loose wires on the bike. There could possibly be more but I really searched that thing good. My question is how can I go about testing to find where the drain is at? I'm really not great with electrical things but i'm trying to get better. If anyone has any help please let me know. Thank you!

The vid you posted is a good guideline - to do this quickly and effectively you will really need to use a multimeter. On these old bikes there are few fuses to pull, so you'll probably need to resort to unplugging components.

The diodes in the regulator/rectifier can and will wear, and will eventually get to the point where they drain. It's unlikley these will result in a flat battery overnight though.

One thing to check first though - some bikes (many KZs) have a 'park' mode which will keep the lights on with the key removed, I believe this was designed for deliveries so the bike could be left visible while stopping for short periods. Check that all lights are off when you switch it off (a sticking brake will cause this problem too). I once lent my bike to a friend and he thought the battery was draining because he kept parking it with the lights on.

In an attempt to provide some help I could use some more info. I am by no means an expert on the 400 models, but think that 2 different versions were offered in 1975.  The D1 version and the S1 version. There are differences between them.  The D1 had a front disk and an electric starter stock.  While the S1 had a drum break in front and no electrical starter. I understand that there could of been many changes since new, but which type of break and starter does your machine have.  You indicated that there had been changes made to it.  Does your still have the stock keyed switch? Do you have a wiring diagram for you bike?

In general on the stock wiring system power travels from the battery (depending upon if you have an electric starter) it splits one to the starter relay and one to the fuse. If no electrical starter then it just goes to the fuse.  From ;the fuse it travels to the keyed switch. If tested there should be power to the switch, but if the switch is working correctly there should be none coming out of the switch with the key removed or turned to off. If after testing with the key removed or off there is power coming out of the switch it would be the first thing I would look at.



 

Check that all lights are off when you switch it off (a sticking brake will cause this problem too). I once lent my bike to a friend and he thought the battery was draining because he kept parking it with the lights on.

Thank ill definetly try to look into this. The harness is just a bit chopped up so I thought it would just be a loose connection or something but the front break does squeek a decent bit when I move it around the garage and I dont have a break light or turn signals hooked up so maybe that could be it. 

Its a D1. And yeah I did find the wiring diagram for it and I can somewhat understand it but not really. 

wrote:

One thing to check first though - some bikes (many KZs) have a 'park' mode which will keep the lights on with the key removed, I believe this was designed for deliveries so the bike could be left visible while stopping for short periods. Check that all lights are off when you switch it off (a sticking brake will cause this problem too). I once lent my bike to a friend and he thought the battery was draining because he kept parking it with the lights on.
 

I don't believe US-spec KZs came with that feature. I think we have just on, off, and lock.

The early 1972 Zed´s comes with an OFF, ON and POS ignition switch and a seperate steering lock on the lower triple or steering neck.
The later 1980 models comes with a LOCK, OFF, ON, POS ignition switch.

Ok does anyone have or know where I can find a high resolution wiring diagram? I found one but its just a jpeg so when I try to zoom in it gets pixilated as hell. 

I do not know if the version of the wiring diagram I have will provide any better or clearer image.  It is a pdf but it was pulled down as a jpg and converted into a pdf.  I have attached it below.

Just as an aside there is lots of good info at this site www.kz400.com .  Keep in mind the site is up but I do not think much has been added to it since its creator passed several years ago.

Thank all for the replies so far. I'm going to start testing soon but upon closer inspection the harness is a bit rougher than I originally thought. Still I am going to try and save it. Although does anyone have a diagram or pictures specifically for the rear turn signals and brake light connector? I have the original fender with the connector but the main harness side was all cut up and miss matched because the pervious owner did some cafe racer style stuff. I dont think he even hooked them up right because they didnt work becore I pulled them apart but he only had four wires insted of the factory five. They were also different colors from factory but I could see where he just spliced in new wires at the end but the factory wires connected to them did not match the wiring diagram. There was a pink and an orange and no grey so idk where to go with this now to find the right wires. Thank you.

Alright so I checked and I have a parasitic drain of 2.5 amps. I pulled the 3 main fuses near the battery and that had no effect on the amp draw so Im not too sure how to check it now. Also some of the 10 amp fuses were replaced with 20 amp ones which is a bit concerning, but those circuts don't seem to be the problem of the parasitic drain. What else should I do to check for it?  Thank you.