77 Kawasaki KZ750 Electrical Question

VintageMBike

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A few weeks ago, when it was FREEZING, the KZ750 sat out for 10 days but i took out the lead acid battery, brought it into the house, and put it on a tender.

When the cold weather broke, I went to put the battery back in the bike, BUT as I was doing so, the negative ring terminal on the battery wire from the bike, broke off. I did a quick fix, using another ring terminal and 10 gauge wire (probably a mistake since the wire to the starter is heavier gauge).

I tried to start the bike but it seemed like it had no spark. During the process of trying to start it, I flooded the carbs. So I changed the spark plugs and gave it another go. It ran great for about 15 min, idling. I then hopped on the bike to take off, and the bike shut off. Tried to kick it. nothing. When I try to use the electric start it engages but makes this awful clacking noise if I try too long.

Fast forward to today:

Took off the 10 gauge quick fix wire and crimped a ring terminal over the old wire on the ring terminal. Job done

Last night I charged the battery on a tender last night. Its shows 13v. This morning I put it on the bike, with new spark plugs, and after a few kicks it started right up.

I checked the voltage at the battery while the bike was running and it was 14.4v

Issues:

I noticed the neutral light no longer comes on, but thats ok.
The brake light no longer comes on.
I changed the bulb - the running light came on at first, but now it doesnt..

Went for a ride and stopped for a minute. Started up OK but the starter made that weird AWFUL "trying" noise again.

Got back home, and with the bike idling, turned on the headlight. The bike died immediately.

What gives?
 
Sounds like your starter clutch is going out. super common on these bikes.
 
doc_rot said:
Sounds like your starter clutch is going out. super common on these bikes.

Nope. Im prertty sure its an electrical problem. I cant even kick start the bike. No spark it seems. It only happened when I spliced the wire. And its no coincidence the lights dont work.
 
I've got a 78 myself. Have you checked for spark by laying the plug against the head and cranking it over? You should see a nice blue spark. On the clacking noise, that happens on mine, too, if I crank too long. What I think is happening there is the gear behind the starter clutch gets worn where the starter clutch grabs onto it and starts to slip if cranked too long and the noise might be the starter clutch slipping around it. I've got a rebuilt starter clutch so I don't think in my case, anyway, it's that part going bad. If you haven't rebuilt your starter clutch, I would recommend it. It sounds like you've got a bad ground. If you have a wiring diagram, check all circuits for ground continuity with a multimeter. That's my $.02.


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Armaundk said:
I've got a 78 myself. Have you checked for spark by laying the plug against the head and cranking it over? You should see a nice blue spark. On the clacking noise, that happens on mine, too, if I crank too long. What I think is happening there is the gear behind the starter clutch gets worn where the starter clutch grabs onto it and starts to slip if cranked too long and the noise might be the starter clutch slipping around it. I've got a rebuilt starter clutch so I don't think in my case, anyway, it's that part going bad. If you haven't rebuilt your starter clutch, I would recommend it. It sounds like you've got a bad ground. If you have a wiring diagram, check all circuits for ground continuity with a multimeter. That's my $.02.


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Will do. And thanks for responding.

Since the brake light doesnt work when I use either the front or rear. ive ordered brake switches from Z1 (they are cheap) and a new ignition coil and battery just in case. I'll be testing over the weekend.
 
Armaundk said:
I've got a 78 myself. Have you checked for spark by laying the plug against the head and cranking it over? You should see a nice blue spark. On the clacking noise, that happens on mine, too, if I crank too long. What I think is happening there is the gear behind the starter clutch gets worn where the starter clutch grabs onto it and starts to slip if cranked too long and the noise might be the starter clutch slipping around it. I've got a rebuilt starter clutch so I don't think in my case, anyway, it's that part going bad. If you haven't rebuilt your starter clutch, I would recommend it. It sounds like you've got a bad ground. If you have a wiring diagram, check all circuits for ground continuity with a multimeter. That's my $.02.


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Problem solved. I changed the lead acid battery to a Deltran Battery Tender Lithium IRON PHOSPHATE battery, and took out the old igntion coil, replacing it with a new emgo one and voila, bike runs fine!!
 
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