no spark, 'Gerex' electronic ignition, 1978 kz1000

You will probably have to figure out what wire goes to the left and right coils for the Kawasaki hook up, but it's pretty much the same as I remember when I converted my 77 Kz1000 from points to the Gerex system(I had the older externally mounted module mounted back by the right rear shock like shown in the diagram).

If the system still works, it will put out an incredible amount of spark.

On my 82 GPz 1100 B2 the left coil fires #1 and #4 cylinder with the primary(small wires)being RED and BLACK.

The right coil fires #2 and #3 with the primary wires being RED and GREEN.

TerryK wrote:

PLUMMEN wrote:

before pitching the ignition id first check to see if its getting power to it

Ditto.

And check the kill switch

Always look to the simple things first.

JR wrote:

TerryK wrote:

PLUMMEN wrote:

before pitching the ignition id first check to see if its getting power to it

Ditto.

And check the kill switch

Always look to the simple things first.

I had not checked the kill switch during my test so after reading your suggestion I was super hopeful but upon checking, the bike's 'Run/Off' switch was on 'Run'.

I've read the PDF that Bluemeanie posted (thanks again!) and I have a question for MFolks -- my wire colors coming from the Gerex are close but not quite the same as the Honda Gerex .PDF manual. Here's what my kz1000 Gerex wiring looks like:

1) a 4-wire harness coming out of the Gerex box that's
mounted under my seat -- the 4 wire colors are:
Brown, Yellow, Green, Orange. These go into a Molex
connector, and the other side of the Molex connector
has the same 4 colored wires (no surprise there I
reckon) and routes down to the points cover on the
right side of the engine where the Gerex rotator is
installed.

2) a red wire that goes into a red-colored connector, and it is not going to the coils

3) two other wires -- a Gray wire and a Purple wire -- that go to the coils.

I'm checking this at night so I can't assess the exact coil connections.

But this is quite different from the Honda setup in the .PDF file I've got -- the Honda has not only the Gray and Purple coil wires, but a White wire and an Orange wire that also are supposed to be there, connecting to the coils.

So I have a question for MFolks -- should I be worried about the 'missing' White and Orange coil wires? How does my 2-wires-to-the-coils setup remind you of your 1977 kz1000?

Also: the stock plug gap for the kz1000 on NGK B8ES plugs is .6 to .7mm. The Honda Gerex installation is calling for a plug gap of .063 to .065, which equates to
a HUMONGOUS plug gap of...around 1.63mm! This is tripling
the stock kz1000 spark plug gap, again MFolks -- does
this sound right?

Okay, new info -- I got after it a bit despite the darkness (9:30pm West Coast time) and found this:

1) The Gray and Purple wires from the Gerex box go to the green and black wires coming from the 2 coils (these green and black coil wires are in the kz1000 wiring diagram). So that jibes so far with the Honda Gerex install manual.

2) I was wrong about the Red wire coming from the Gerex box -- it *does* in fact go to the coils -- it's connected into a dual-connector with the Gerex red wire on one side, and on the other side of the connector are two yellow/orange wires that the kz1000 wiring diagram shows as coming from the 2 coils.
There's also a wire there leading into the wire harness that I can't quite see, I'll check tomorrow, probably goes to the ignition as called for in the Gerex manual.

So basically my Prior Owner connected this Gerex box as follows:

- The Gerex box's Gray and Purple wires to the coil's gray and black wires

- The Gerex box's Red wire connected to the other two coil wires which are both orange/white


I also checked the 3 fuses on the kz1000 -- none of them are blown.

The only other thing is that the black ground wire coming out of the Gerex box on my kz1000 is *not* connected to the battery '-' terminal -- the prior owner connect it to a frame grounding screw that's on a frame cross member under the seat. The Honda Gerex install manual says that's a no-no:

"Black ground wire MUST go on the '-' battery terminal and NOT on the frame. The system will not operate properly unless the ground is to the '-' battery terminal."

MFolks, does the comment about the black wire ring true for your memory of your Gerex install on your '77 kz1000?

The Negative battery connection sounds right. For some reason it needed a good electrical connection to the battery.

MFolks wrote:

The Negative battery connection sounds right. For some reason it needed a good electrical connection to the battery.

It's because the unit fires with a very fast rising voltage so the unit's ground return will have fast rising current spikes. You need a short, low inductance path to the negative of the battery or else the unit will "bounce" on the ground spike each time it fires.

bountyhunter wrote:

MFolks wrote:

The Negative battery connection sounds right. For some reason it needed a good electrical connection to the battery.

It's because the unit fires with a very fast rising voltage so the unit's ground return will have fast rising current spikes. You need a short, low inductance path to the negative of the battery or else the unit will "bounce" on the ground spike each time it fires.

Okay, thanks for that, I wasn't quite understanding why the Gerex box needed to be directly connected to the battery's '-' terminal because -- as per the Kaw factory shop manual for the kz1000 -- the battery's '-' terminal is connected to the right rear upper engine mount meaning that *electrically* the '-' battery terminal is grounded to the frame and engine case. And I checked and verified that indeed, my '78 kz1000's battery '-' terminal wire runs directly from the '-' pole on the battery to the upper right rear engine mount.

The prior owner didn't follow the Gerex install manual -- he connected the Gerex ground wire to the frame, at a point under the seat on a frame cross-member that
has a screw where another of the bike's electrical component is connected for a ground.

I guess the Gerex unit's grounding requirement is "Yes, I *know* I'll get back round to the battery's '-' terminal eventually -- but don't make me go through the frame to get there!"

Used to be 2 systems by Gerex Multifire in the 70's, one that i used in my nitro burning z's which was a total loss system and one that hooked up to the normal charging system.
these were the ignitions to have in this era but the main downfall of them was the pick/up sensors that replaced the points were very fragile in that if you had the plugs out and the ignition on and you happen to turn the motor over and not have the spark plugs earthed the pick/sensors would fail instantly,recall showing a fellow racer how big a spark they threw around 2 inch holding the spark lead from the head and looking foolish when it stopped sparking for good,also recall that both systems had to have the main boxes mounted out front on the 2 front tubes to get a lot of cooling air to them or they would cack themselves too.
have some wiring diagrams somewhere but spent 3 hrs looking for them and have not found them so far but will post when they come to light.

Also recall the main boxes were an irradesant red and black in colour and both had to to be mounted in the front airstream to live. and other drawback against to todays ignitions was the lack of ignition retard spark

joe k wrote:

Also recall the main boxes were an irradesant red and black in colour and both had to to be mounted in the front airstream to live. and other drawback against to todays ignitions was the lack of ignition retard spark

Thanks Joe, esp. for the 'keep the plugs earthed' tip. So far so good, I'm ready to reinstall the freshly-clean carbs and cleaned gas tank/petcock and test fire it but have been too busy with work. Hope to get to it this week, and I'm hoping the Gerex is OK! Sounds kinda fragile.

And I am getting spark -- what amazes me is that an electronic ignition that is 31 years old is *still* working at all. The Gerex company really had
something back then apparently.

Gerry was a pretty cool guy. The GEREX CDI on my '73 Z1-900 lasted 27 years. It would have lasted longer had I not had overcharging problems I'm willing to bet. The GEREX CDI on my '78 KZ1000 has been running since 1984.