'77 KZ-1000A1 No-Start Question

I have about 450 miles on my KZ since the rebuild and have sorted out most of the problems I had since then. I have one nagging issue that I can't locate or resolve and hope someone may be able to shed some information my way. I have a VERY erratic no start situation with my electric starter. It may start on demand 20 times, but then on 21 nothing happens when I hit the start button. Now if the darn problem would just stay put I could try to track it down, but invariably within a couple of start attempts it fires up. On two occasions, while I was out riding of course, the bike refused to start and I had to resort to the kicker. I more than realize that these types of problems are difficult to diagnose "on line", but has anyone else experienced this problem and figured out what the cause was? Note that when this happens there is no noise from the bike such as clicks or clacks or anything. The lights don't dim, nothing from the bike. Any thoughts guys? I don't believe it has anything to do with the safety switch on the clutch lever but who knows...Thanks in advance...
Rick H.

My first thought is, check the starter button is burned or need a good clean and de-oxid task.
And do check the connector plugs that route to the starter relay.

Three things come to mind:

#1: Ensure your ground straps are clean and tight at both ends.
#2: Troubleshoot or try a different starter solenoid
$3: As suggested above, clean start button contacts.

All of the above should be checked first but...did you rebuild your starter? Sometimes they just need a good cleaning and a new set of brushes.

Rick H,
If I read correctly that when the problem presents there is no noise. That would lead me to focus on the control wiring. As mentioned the clutch interlock, the off run switch on the right hand control,and the start push button. If the solenoid was clicking then I would be looking at it, or the starter.

Thinking further check the connection Of the black wire and the black/yellow on the solenoid. Black/yellow is ground and black is the power feed through the start button. The wiring Schematic shows they both have bullet connectors. If either are bad or corroded it would stop the solenoid from firing.

On my '77 A1, the clutch lever does not have to be pulled in to start if the bike is in neutral. If there is no turnover while in neutral, that should eliminate the clutch lever switch .

Others smarter than I can confirm this. Partzilla shows the 1977 kz1000 a1 as having a clutch interlock circuit.

BCScott wrote: On my '77 A1, the clutch lever does not have to be pulled in to start if the bike is in neutral.

Edit: Had to eat crow on my original response - had the years wrong. I think on the 77's you need to pull in the clutch to start, even in neutral. If you don't need to, someone has bypassed your clutch switch (or the switch is broken)

The only diode I see in the Wiring Schematic is on the trun signal flasher relay. Where is the one you mention. I’m asking to learn for future diagnosis. There is no mention of a diode in the testing process.

Mikaw wrote: The only diode I see in the Wiring Schematic is on the trun signal flasher relay. Where is the one you mention. I’m asking to learn for future diagnosis. There is no mention of a diode in the testing process.

I'm afraid I led you astray. I think the diode was added to later models (79 ???). I thought my 77 had it but after searching it appears not.

Mikaw wrote: Others smarter than I can confirm this. Partzilla shows the 1977 kz1000 a1 as having a clutch interlock circuit.

cb900f wrote: I think on the 77's you need to pull in the clutch to start, even in neutral.

Of the UK bikes only the 650 had a clutch switch. 1000's did not. No 900's had a clutch switch either, I have originals of all three.

Thanks to everyone that responded to my question/problem. I was hoping just by chance, someone may have had the same situation arise and could point out what they did to repair it. This issue is greatly compounded by the fact it is completely intermittent. Then when the starter doesn't work usually one or two further start attempts will get it working. Now that by itself wouldn't be bad save for the fact when I was out riding on two occasions it decided not to start despite continued attempts, but when this happened I wasn't home and could not try and trace the problem down. When that happens it is really nice to have a kicker! As I stated earlier when this situation crops up there is absolutely nothing happening when I push the start button, no noise at all and the lamps don't dim to indicate any current draw. Very frustrating to say the least. My gut tells me it is not the starter because the solenoid isn't doing anything to indicate it is working. My KZ does have the clutch interlock lever switch as I have the contact switch and wires on the clutch lever perch. Even if the bike is in neutral I must pull the clutch lever "in" to start it. Thanks again to all!
Rick H.

P.S. Just thought I would add that Warren3200gt's collection drives me nuts with envy! When do you find the time to ride them?