TOPIC:

A big hello... new member here. My son AJ just picked up a 78 KZ400 (B1)...7K original miles that has been sitting for 30+ yrs ...for $50 .
We got engine to turnover, cleaned carbs, working thru rebuilding front brake (MC and Caliper).... but we arent getting any spark (at plugs or at cont.breaker points). I havent done any electrical troubleshooting yet (not my strong suit) , but in your opinions where should I look first.
1) Regulator/Rectifier 2)Ignition Coil 3)Condensor looking thing next to contact points ? 4)Other.
Hoping for a quick fix.. Just thinking that one of these things would simply crap out on a bike that had been sitting for 30+ yrs.
Oh, and Yes.... next time I will do some more diligence on the issue when coming to the forum for help

Welcome. Start at the switches. Kill switch etc. Fuses too. Pics?
Steve

aye; Swest speaks true, the ignition coil power runs through the kill switch on the handlebar, corrosion there will do that.
I seem to remember disassembling and repairing it; not sure.
The stock fuse box is a good thing to get rid of. Replace it with any good 3 fuse holders you can get.

The headlight power runs through 3 switches and all over the bike before arriving at the light bulb. I added a pair of Hella headlight relays; the difference was huge.
Change to halogen.
The KZ400 can power a 100w light. probably not legal where you are though.

Are any other electrics working (head light, turn signals, brake light, etc)? I assume you got a new battery.

After checking the electrical connections and making sure current is flowing everywhere it should be I'd start at the easiest, cheapest and most likely stuff first.

1. Check fuses. Even if they look good they are old and might not be good. Might be a good idea to replace them anyway.
2. Points and condenser. They are cheap and easy to replace.
3. Plugs (if you have not already) and plug wires. Originals may be permanently connected to coils so you may need to replace everything.
4. If nothing still then check out the coil and replace if necessary.

Only after those things are exhausted would I start looking at other things like regulator/rectifier, etc.

Would first assure that 12 volts is being received at the ignition coil primary terminal (perhaps via a small red or red/yellow wire).

In event 12 volts is NOT being received at the ignition coil primary terminal, will then need to determine why 12 volts is NOT being received at the ignition coil primary terminal.

Good Fortune!

Good Fortune!

When checking the fuses, also check the solders on the wires going into the fusebox itself.

And,of course,check that you have fresh liquid in the indicators.Easy to forget sometimes.

Thanks for responses.
Yes all lights are working and starter turns. Just no spark. Full charged battery... Fuses look good.
I'll check kill switch for corrosion. I'll Replace fuses, wires, plugs, points and condensor for good measure and report back.

May eventually go minimum wiring with kick only....

Thanks mike

davido wrote: And,of course,check that you have fresh liquid in the indicators.Easy to forget sometimes.

Did you just suggest that he should check the blinker fluid...?

MRKZ400 wrote: Thanks for responses.
Yes all lights are working and starter turns. Just no spark. Full charged battery... Fuses look good.
I'll check kill switch for corrosion. I'll Replace fuses, wires, plugs, points and condensor for good measure and report back.

As someone else mentioned, you might want to replace the OE fuse box with modern blade-style fuse holders. Finding AGX (.25" x 1.0") fuses is difficult (or impossible) unless you go mail order.

Absent battery positive voltage to the ignition coil, MRKZ400 is just blinker-fluiding into the wind.

Good Fortune!

Nerdy wrote:

davido wrote: And,of course,check that you have fresh liquid in the indicators.Easy to forget sometimes.

Did you just suggest that he should check the blinker fluid...?

Of course! People tend to neglect this,which can lead to the indicators (blinkers) drying out, which in turn leads to a whole load of other electrical problems.
The workshop manual covers this.