1978 kz650 no spark? please help!

Fella, you have two sets of points/condensors. One on the left has a BLACK wire coming off it. This wire tells the coil when to fire. This wire goes to the right hand coil generally. The wires off the right hand coil go to the 1 & 4 plugs. The right hand points/condenser have a GREEN wire connected. These go to the LEFT hand coil (as you sit on the bike) and the plug wires from that coil go to the 2 & 3 spark plugs. There is another wire connected to each coil coming off a tee connector. It is yellow/red. It is the power from the bike that powers the coils. To measure, you turn on your key and put your POS multimeter probe on the lug on the coil where this wire connects and the NEG probe on a frame ground. You should see about 12VDC. If you have BOTH the black and green wires from the left and right points/condensors connected correctly and you get no spark and you DO have power going to the coil, the problem is that the condensor is very likely shot on both sides. I doubt the points/condensor from a 750 twin will work... BUY A DYNA S electronic ignition and save yourself some money in the long run as they outlast a set of points/condensors many times over.

POINTS

Sorry about the large but crappy pics. Here is one of the wires I was concerned about. AND I know that a dyna is the way to go, but that my not be my problem and until it fires the way it is, I am not dumping another $200 into the dyna s.

The undertank wiring photo isn't very clear,
but shows enough to indicate the wiring connections
may be wrong.

The red/yellow harness wire located under the fuel tank
has a tee connection that feeds red/yellow to the leftside
coil and also feeds red/yellow to the rightside coil.
In other words, each coil gets a red/yellow connection
to one of its terminals. This is the switched battery
positive input into the coil.

The green harness wire located under the fuel tank
has a single connector that is supposed to connect to
a green wire going to a coil terminal of whichever coil
is firing the inside sparkplugs. In other words, the coil
firing the inside sparkplugs has only a single yellow/red
wire to one terminal and a single green wire to the other
terminal. Simply put -- the coil firing the inside sparkplugs
gets only a yellow/red to one terminal and only a green wire
to its other terminal.

The black harness wire located under the fuel tank also
has a single connector that is supposed to connect to a
black wire going to a coil terminal of whichever coil
is firing the outside sparkplugs. In other words, the
coil firing the outside sparkplugs has only a single
yellow/red wire to one terminal and a single black wire
to the other terminal. It's easy -- the coil firing the
outside sparkplugs gets only a yellow/red to one terminal
and only a green wire to its other terminal.

Don't obsess with the colors -- but DO obsess with this:
the coil firing the inside plugs is signaled by a wire
from the righthand side points; and the coil firing the
outside plugs is signaled by a wire from the lefthand
side points.

Good Luck!

Id also make sure the wires feeding the points & condensor are not grounded where they attach to the points, make sure the little fiber insualtors are on there and were not left out by the previous owner. Maybe thats why he sold it, he couldnt get it to run either

Am more accustomed to seeing the condensers mounted
whereby the wires exit from the engine side of the
backing plate (the solder joints being hidden from
view) and loop back through the backing plate to
their respective attachments to the point bases.

Perhaps the solder joints shown in the photo
(facing to the outside) are contacting the
point cover and shorting out against the point
cover when the point cover is installed.

Just a guess. If not already done,
could leave the point cover off while attempting
to gain spark. Good Luck!

In the photo of wires entering the points area,
it appears to show a red and a blue wire.
What's up with that?
Supposed to be only two wires entering the points area,
namely a black wire and a green wire.
The black wire from the leftside points
goes to the coil firing #1/4,
and the green wire from the rightside points
goes to the coil firing #2/3.

Regardless of wire color, the connections
should be as stated (left-points to #1/4 coil,
and right points to #2/3 coil).

Good Luck!

is that red/blue wire go to the oil pressure switch?
i dont remember what stock color is on the 650 but my dyna-s came with a solid blue one!

steveo_4192003 wrote:

is that red/blue wire go to the oil
pressure switch? i dont remember what stock
color is on the 650 but my dyna-s came with
a solid blue one!

Should have noted my frame of reference being Z1 and KZ900.
Am now understanding that the KZ650 points
ignition system may have one or more additional
wires from the harness entering the points area
besides the two signal wires for the coils.

In addition to the two coil signal wires,
the Dyna-S ignition on Z1 and KZ900 is powered
by a third "red" battery positive wire into the
modules (three wires from the harness entering
the points area). Other models may have two
separate power wires (red?) -- and I just learned
from steveo that a "blue" wire may also be present
with some Dyna-S ignitions.

Also, just looked at the 1978 KZ650 wiring
diagram which confirms a red/blue wire going
to the oil pressure switch, as steveo suggested.

Good Luck!

Thanks so far but you have just repeated what has already been done.
What about that open connector in the picture?.........
And Could the rectifier cause the bike to not spark? The coils are both gettng 12dcv of power?

WHY wont this work?

No blown fuses and no bad parts...

HOW DO I CHECK THE GAPPING OF THE POINTS?

superman63086 wrote:

Thanks so far but you have
just repeated what has already been done.
What about that open connector in the picture?.........
And Could the rectifier cause the bike
to not spark?
The coils are both gettng 12dcv of power?

WHY wont this work?

No blown fuses and no bad parts...

HOW DO I CHECK THE GAPPING OF THE POINTS?

Thanks so far but you have just
repeated what has already been done --
but something which has already been done
by somebody has been done wrong.

What about that open connector
in the picture? --
As shown in the photo, the dual connector
from harness green wire has only a single
connecting green wire coming from the dual
connector, which presumably attaches to
a #2/3 coil terminal, and the green harness
wire is presumably the signal wire from
the righthand points. If these presumptions
are correct, the unused dual connector hole
may be ignored. All of which is consistent
with previously posted information.

As shown in the photo, the dual connector
from the harness red/yellow wire has one
red/yellow wire hooked to it and one
black wire hooked to it.
The red/yellow wire from the connector
is supposed to attach to a #1/4 or
#2/3 coil terminal. The other wire
from the connector is supposed to
be another red/yellow wire which
attaches to the other coil terminal.
Because of this, the "black" wire is supicious.
But the "black" color is okay
(any color, even polka dot, would be okay)
so long as it connects to a coil terminal
on the coil not already served by the
existing red/yellow wire from the
dual connector. All of which is
consistent with previously posted information

And Could the rectifier cause the bike to not spark?--
Not likely here in this case where each
coil is reportedly already getting 12 volts DC
(one coil being served by a red/yellow 12 volt wire,
and the other coil being presumably served by
a "black" 12 volt wire).

The coils are both gettng 12dcv of power?--
Hoping the question mark is a "typo"
and that each coil has one primary terminal
being supplied with positive battery voltage.

WHY wont this work?--
Can't think of anything not already
covered in earlier posts, especially where
there are No blown fuses and no bad parts.

HOW DO I CHECK THE GAPPING OF THE POINTS?--
By using a feeler gauge.

Good Luck!

OK yes the "?" was a typo.
They are getting 12dcv
Thanks for the clarification on the rectifier.

And now that I now how to check the gapping, what are they suppose to be gapped at?

CAN the points gap and still be BAD? And could someone have messed with the points previously and screwed with the timing so that it wont spark?

Just trying to narrow the playing field I am running out of options.

Thanks.