Noobie Kz650 Ignition and/or Coil Questions

I am a new memeber here and would like to thank you for your responses up front. Im having as issues with my #3 cylinder not firing. The bike is a/was a 1977 kz650B. from the pics below you can see it has a few other model year parts on it.

The problem: cylinder 3 not firing (cold exhaust when running and does not bogg when I unplug the spark plug wire at idle, but does with removal of other cylinder's spark wires.

Things I have done:
1)Compression test = 120(+/- approx 8)on All cylinders
2)Cleaned, synced and adjusted float level on 24mm mikuni carbs (spark plug on #3 is wet and smells of gas when extracted after idling.
3) switched spark plugs from 3 to 1 with 3 still being dead.

Based on the above I cant rule out anything, but it looks to be an electrical issue somewhere before the spark plug. I am going to get a multimeter this week to eval the coils.

I have included pics of the ignition, which i know nothing about, and the coils ( installed and extra set)

I am sort of lost as far as where to go from here. any input is appreciated.
thanks Nick

when you say switched plugs do you mean just the plug itself? i would swap coils and see if its a beat coil, also pay attention to wires as it may be a wire.

I was going to switch the wires between 2 and 3, but the wire for #2 is too short to reach #3 and the wires are not removable form the coil. I guess i could switch the side the coils are mounted on and that would give me a little more length on the spark wires.
Thanks,
Nick

There's a non-serviceable 5000 ohm resistor in the sparkplug cap, that can go bad due to heat and vibration. New ones are available at most Japanese motorcycle shops or www.z1enterprises.com .

The test the caps,unscrew them from the sparkplug wire, and then use a multimeter set on OHMs, range of 20K (20,000 OHMs). Put one probe whre the sparkplug went, and the other probe where the sparkplug wire went. If the cap is any good, you should get a reading. When replacing the sparkplug cap, do all of them as a set, and cut back about 1/4" of the sparkplug wire for better electrical contact.

You should swap the 2-3 spark plug wires, not 1-3, to see if the problem follows the wires. If the wires are too short, you'll have to find a way around that. Perhaps swap the 1-4 coil w the 2-3 coil? Or try the Martek coils? ... they don't look that great, though.

From your attached photos it appears you have an aftermarket Martek ignition system & you also have a pair of stock type coils. I don't know if the stock coils will work w the Martek stuff.... perhaps try the Martek coils? I would test the coils w a meter & inspect them for cracks or damage and look into info for the aftermarket ignition. I did a search & it was stated that the Martek is an optical pickup. I don't know anything about it.

Skyman posted this link in a KZR topic, OldRice.com - Martek Info , but most of the info is for singles.
loudhvx posted some info in this topic. KZRider - 1977 kz650b1 w/martek 440 ignition points

Alright so I had to bolt the coils to the opposite sides in order for the spark cables to reach the plugs. After running all the checks to make sure everything was hooked up, I tried to turn the bike over. The bike sounded like it wanted to turn over but wasn't gonna happen; probably a result of me running the battery down during the compression tests. I attempted a kick start and a very loud pop came out of the pipe. bike still didnt turn over.

I also bought a multimeter and on both coils the primary reading was 4.2, 4.3(factory is 4) and the secondary was 14.25, 14.75 (factory is 23) does it seem likely that this is a coil issue?

thanks,
Nick

NickMac wrote: Alright so I had to bolt the coils to the opposite sides in order for the spark cables to reach the plugs. After running all the checks to make sure everything was hooked up, I tried to turn the bike over. The bike sounded like it wanted to turn over but wasn't gonna happen; probably a result of me running the battery down during the compression tests. I attempted a kick start and a very loud pop came out of the pipe. bike still didnt turn over.

I also bought a multimeter and on both coils the primary reading was 4.2, 4.3(factory is 4) and the secondary was 14.25, 14.75 (factory is 23) does it seem likely that this is a coil issue?

thanks,
Nick

Doesn't really matter how the coils are physically mounted to the bike, and the coils will function even if not physically attached to the bike (suspended in mid-air would be okay), so long as wired correctly.



Of the two separate ignition coils, one of them is supposed to fire the outside spark plugs number 1 and 4.
And the other ignition coil is supposed to fire the inside spark plugs number 2 and 3.

Whichever ignition coil is firing outside spark plugs 1 & 4, must receive its instructions from signals emanating from the left-hand (9 o'clock) points or module located underneath the points cover.

Whichever ignition coil is firing inside spark plugs 2 & 3, must receive its instructions from signals emanating from the right-hand (3 o'clock) points or module located underneath the points cover.

With points and with Dyna-S, the signal wire from left-hand (9 o'clock) component under the points cover routes directly to whichever ignition coil is firing outside spark plugs 1 & 4.
And the signal wire from right-hand (3 o'clock) component under the points cover routes directly to whichever ignition coil is firing inside spark plugs 2 & 3.




With Kawasaki's stock igniter style electronic ignition, the signals emanating from pick-up modules located underneath the points cover are routed through an igniter (usually located under a side cover) before attached to the primary terminals of the ignition coils.




See the wiring diagrams available in KZr's FILEBASE.

Good Fortune!

Where satisfied that the ignition coils' wiring is correct,
if not already done,
would assure that the rotor part of the timing advancer is correctly installed,
and isn't installed 180° out.

Good Fortune!

Thanks Patton! those diagrams have been a live saver. I appreciate everyone's responses and look forward to becoming part of this community.

thanks,
Nick

Regardless of which particular ignition system is fitted, the whatever system serves to successively ground and unground the primary windings of the ignition coils.

While the primary winding is reaching ground via whatever system, the ignition coil is "charging."

When the whatever ignition system ungrounds the primary winding, such ungrounding is the event that causes the ignition coil to "fire" through the plug wires.

With points, it's the opening that ungrounds.

With Dyna-S, it's the embedded rotor magnet passing a pick-up module that ungrounds.

With stock Kaw igniter, it's the rotor pointer passing a pick-up module, in concert with the igniter, that ungrounds.

With Martek, it's a light beam through a hole in the rotor.
Would guess it's the light beam shining through the hole, in concert with a transistor, that ungrounds.


Here's an excerpt (from the link below) about the Martek ignition system.

System Description and Function
The purpose of the Martek 440 aftermarket retrofit kit is to convert a conventional "Kettering" motorcycle ignition system to an electronic breakerless, light emitting diode, ignition system.

The system utilizes light emitting diodes and light sensitive detector transistors which conduct current to the induction coils.
Switching is effected by a hole in the rotor which opens and closes the light beam. The output of the light sensitive transistors is then amplified to turn a power transistor on and off which interrupts the coil primary current flow, inducing a high voltage in the secondary coil.

I would revise the last bit of text to say, ... interrupts the ignition coil primary current flow, inducing a high voltage in the [strike]secondary[/strike] ignition coil.

Click here > arb.ca.gov/msprog/aftermkt/devices/eo/D-101.pdf


Good Fortune!