Won't start after rebuild

since the spark is weak in the open air it is even worse under the cyl pressure, I see that you are still using the stock points, have you checked the condensers and the points to make sure they are good,
and since it is popping through the carbs have you checked the valves to make sure nothing is tight

make sure the point springs aren't grounding against the timing plate.

If you are using a stock IC Igniter ignition, the plug between the igniter and pickup coils should keep you from connecting that part incorrectly. OUT of the igniter is a red wire (power) and a GREEN wire and BLACK wire. I know you have been over this a zillion times but the 2/3 coil becomes the 2/3 coil when connected by the green wire. Check the coil connected by the green wire and see if the plug wires are going to the 2 and 3 spark plugs. It sure sounds like you have the two ignition leads hooked up backwards. The black wire makes whatever coil it is hooked to the 1/4 coil, of course.

I wonder about a short between the points and the plug wires. This is a stumper. If you are fed up with dealing with it an aftermarket ignition might be the easiest solution.

Did you check the battery before you installed it? Is your ground solid?

If not already done, could remove points cover and look inside while spinning engine over in an effort to crank.

Should not see a lot of sparks flying around in there.

The ignition doesn't use points - it's got pickup coils that are pulsed by a flying cam (that is part of the mechanical advance). Those pulses go to the IC Igniter where they are amplified and conditioned. They are allowed to pass to the Ignition coils when the IC Igniter connects the ground. The Ignition coils have B+ connected all the time and only fire the spark plugs when the ground is connected via the black and green wires of the Ignition coils.

I just finished running a test wherein I ran a wire directly from the B+ to the red lead on the Ignition Coils (as the bike is wired in the harness). No change in behavior. I ran a wire from the B- to the cylinder head. No change in behavior. The problem of the weak spark is not in the engine ground or power to the Ignition coils.

As previously stated, I have checked the IC Igniters (all seven I own now, thanks to eBay) to be good and tried each of them. No change in behavior. I have changed the ignition coils with ones from my like-a-top-running '85 GPz750. No change in behavior. I have checked the resistance of/bypassed all the wiring in the ignition system. I have swapped the pickup coils with the other two sets I own (thanks to eBay). No change in behavior. I swapped the black and green leads. Ran worse, tried to fire through the carbs. The wires are not hooked up backwards, they're just not. The flying cam/mechanical advance isn't on backwards or reversed - it only goes on one way. The battery is newish, holds a 14V charge, and will crank the motor all day.

I am stumped.

Am understanding known good coils from the like-a-top-running '85 GPz750 have been transplanted into the '82 KZ750N1 Spectre which then continues the weak-orange spark. If both bikes use same capacity coils, such test would indicate '82 coils are okay.

ran a wire from the B- to the cylinder head. No change in behavior. Coil primary winding has two terminals. One is battery voltage (continuous B+ voltage being reportedly okay). Thinking the other terminal ( ground is momentarily interrupted by ignition trigger whereby coil output is then sent via secondary windings to the plugs. And that the B- is not contiuously grounded (to cylinder head or anywhere else). As interruption in the ground is necessary which directs current through the secondary wiring to the plugs. Don't understand getting any plug spark with B- contiuously grounded to cylinder head.

An internal frayed wire (visually undetectable) between Igniter and B- could be difficult to diagnose. Could try manipulating the wire with ohm meter connected to the wire ends to assure integrity of inside wire by consistant zero resistance.

Still pressing for an answer to this persistent problem.

As long as you are pulling stuff off your GPZ try swapping the battery too if they are compatable. Just for giggles and to exhaust the possibility. Also, does the cam on the pickup coils appear to be scarred, dirty or tarnished in any way or is there ANY debris on the magnets?

frankenchopper wrote:

The ignition doesn't use points - it's got pickup coils that are pulsed by a flying cam (that is part of the mechanical advance). Those pulses go to the IC Igniter where they are amplified and conditioned. They are allowed to pass to the Ignition coils when the IC Igniter connects the ground. The Ignition coils have B+ connected all the time and only fire the spark plugs when the ground is connected via the black and green wires of the Ignition coils.

I just finished running a test wherein I ran a wire directly from the B+ to the red lead on the Ignition Coils (as the bike is wired in the harness). No change in behavior. I ran a wire from the B- to the cylinder head. No change in behavior. The problem of the weak spark is not in the engine ground or power to the Ignition coils....

If not already done, could check integrity of harness wiring between Igniter and B- by disconnecting harness wiring to B- at the coils, and connecting good test wires direct from B- coil terminals to the respective Igniter feed (trigger) source. And with no other connection between B- to ground.

Am suspicious of possible short or faulty connector between Igniter and coils.

Realize maybe beating a dead horse because of voltage to the coils being reportedly okay, but here goes anyhow.

Perhaps already checked out, and maybe not applicable to the '82, but the igniter-equipped 1979 KZ1000 ignition includes a resistor between the ignition stop switch and coil primary winding terminal which resistor limits power to the coils. On the KZ1000, resistor inspection is via ohm test which is supposed to read 1.5 - 1.9 ohms (red wire and pink wire).

Thinking maybe too much resistance might be overly resticting power to coil primary windings.

If not already done, would it be feasible to compare ohm readings of the '82 resistor with readings of the '85 resistor?

And would it be feasible to temporarily by-pass the resistor for a spark quality check?

If you are REALLY frustrated, you can always let me come buy the bike from you and you can start over with something else...:whistle:

Sorry I had misintrepreted the B- reference in your earlier posts. I erroneously thought the B- referred to the coil terminal. Upon re-reading now believe B- means the negative battery terminal.

So it appears testing has already been done with direct connection between battery positive terminal and coils, which would by-pass the fuse, ign switch, engine stop switch, and resistor. Thereby assuring full battery voltage to coils.

Are primary and secondary coil ohm readings within factory specs?