Starter problems

Hello all,

First time post. First KZ 400D.

Heres the low down. I picked up a 1975 KZ400D that cosmetically is in decent shape. Motor turns over and has good compression. Havnt actually started it yet though. I rebuilt both carbs, and tuned up/replaced ignition components. So now ive got good spark. Went to use the electric starter. And it sounded like it was just spinning. So i figured it was the clutch. Pulled the side cover and to my suprise. No chain! So i remedied that with a chain off ebay.

Now to the actual problem. Without the chain installed the starter turns strong. As soon as the chains installed, the starter relay clicks and then nothing.

Brand new battery. 0 ohms across the starter relay. 13 volts at the starter lug. Could the starter just need a refresh? Any ideas?

So why haven't you kick started it? Ed

Grab your meter.

meter on DC V
ignition on engine off
red probe on positive battery post( post is the metal portion of the battery not the metal portion of the cable)
black probe on negative battery post
note voltage

push starter button and note voltage when starter is trying to turn

move red battery probe to the terminal post on the starter
push starter button and note voltage when starter is trying to turn

move red probe to a starter mounting bolt(make sure the metal on the bolt is shiny and clean)
push starter button and record voltage( it should be very close to zero, but note voltage anyway)

These tests will help eliminate the wiring as an issue.

I got it to sputter with starter fluid. And i figured id workout any electrical issues along the way. But no i havnt kicked it over completely yet.

Did all the tests.

Battery had sat for 3 weeks since last charge. So its back on the trickle charger. Numbers are pre charge.

At battery W/ key off: 12.50 V
At battery W/ key on: 11.90 V
At battery W/ key on and starter button pressed: 11.83 V

Starter lug sees battery voltage.
Starter mounting bolt also sees battery voltage.

Thanks for doing the tests.
I've re-read your initial post. I'm wondering if there is a mechanical issue with the engine trying to spin the transmission shaft.
Your wiring seems fine. There could be a mechanical issue with the starter but you mentioned that before adding the primary chain the starter was fine.
That may be the reason why the chain was missing. I wouldn't think that trying to spin a transmission shaft in neutral would not put that much of a load on a starter.
Try to kick it over as Ed said. If the issue is in the transmission then you should feel it in the kick start----unless the issue is the kick starting mechanism..
Try the kick start and report back, but it seems like your starter is fine.

Also a little information to add. I had the side cover off and attempted to turn the starter with the button while the chain was installed. And the chain itself began to spark.

whoa!!

do you think the sparking was from friction or electricity?

wait
Your last meter reading that i had you do.....red meter lead to starter mount bolt. Did you keep your black meter lead on the negative battery post?
Because you should have had close to zero volts and you said you had battery voltage. Which would be close to 12 volts. There may be a short somewhere in the starter. The starter wire isn't fused so this may explain why it hasn't been fixed.

Correct. Negative stayed at the battery terminal. Positive to the starter mounting bolt. And saw battery voltage.

And on a positive note. Some starting fluid and she goes. Got her to idle with the choke on. So the motors good.

Cool,
If you don't mind riding around without the starter then you should be good.
The starter circuit has an issue. My guess is an internal short within the starter.
If you ride the bike i would have you disconnect the cable at the starter. Wrap the cable in electrical tape to prevent it from touching metal.
When you are ready to we can diagnose the starter. Probably a good winter project.

Now to start making it road worthy. Picked it up free from a friend that moved across the country. Itd been sitting for god knows how long.

I appreciate the help!