1978 kz650 no spark? please help!

Have you tested your rectifier? I would take a picture of your points also and post it here. Maybe we can see something.

AutoXN wrote:

... would take a picture of your points also and post it here. Maybe we can see something.

Yes; such as condenser (capacitor) wire connections.

superman63086 wrote:

Here is a quick problem I have noticed, I tested the wires with a multimeter and on the right coil it shows that both of the wires are getting power? The green one and the yellow-red one. Now I am pretty sure thats not right. But I havent unplugged a wire since I bought it. So is it possible that the person before me had 2 grounds and 2 power wires to separate coils?

The primary (low voltage) side of a coil has NO GROUND. It has +12V on the positive end, and it has the other end connected to the points which ground when closed and then open to generate the spark.

If you have confirmed solid +12V to the positive side of the coil, do this:

Disconnect the negative battery cable.

Connect an Ohm meter to check continuity from the negative side of the coil to the points.

Ohm from the negative side of the coil to ground, and turn the crankshaft manually: does the meter read ground continuity when the points are closed and then open when the points open?

If so, the coil secondary should be sparking.

Patton wrote:

AutoXN wrote:

... would take a picture of your points also and post it here. Maybe we can see something.

Yes; such as condenser (capacitor) wire connections.

Good point. The #1 cause of no spark after work being done is the condenser contact is inadvertently installed so that the points accidentally are touching ground continuously.

Been there, done that.

superman63086 wrote:

Here is a quick problem I have noticed, I tested the wires with a multimeter and on the right coil it shows that both of the wires are getting power? The green one and the yellow-red one. Now I am pretty sure thats not right.

Definitely not right.

OK thanks so far but here is the overall situation. When I bought the bike I put a new battery in it and cleaned the carbs. I touched nothing else! IT WOULD NOT SPARK. So now I have slowly started replacing things to get it to spark. It had accel coils 140403 and 8.8 accel wires. I started with plugs, no spark, changed the wires, no spark, new coils, no spark, new condenser, no spark, checked my connections, no spark, checked the points gapping, no spark, cleaned the points, no spark.
But I will post a picture for all of you to help me. And another thing..
How many wires should be comming from the harness where the coils are connected. I have both a yellow-red and a light green wire connected to the coils. BUT there is an EMPTY connection from the SAME set of connections the wires come from on the left coil side. Is there a FRAME ground from that connection or is it suppose to be empty?
Again I will try and post another pic for that as well.

As known, each coil has two primary terminals. Only a single wire connects to each coil terminal.

Switched battery voltage (often a red/yellow wire) feeds one primary terminal on one of the coils, and also feeds one primary terminal on the other coil.

The other primary terminal on the #1/4 coil connects via the black wire to the lefthand side points. The #1/4 coil fires the outside sparkplugs.

The other primary terminal on the #2/3 coil connects via the green wire to the righthand side points. The #2/3 coil fires the inside sparkplugs.

Question please -- was the bike running when acquired before battery replacement and other work?

Good Luck!

The bike was not running and has sat for at least three years. We are clueless and losing hope fast. Will the parts from my kz750 fit his bike(condenser, points, coils)? My bike runs and rides fine, so I know my parts are good, we just want to test. 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!