Engine Not Running on Left Side

I have a 1981 KZ440 LTD, the engine is not running on the left side. It Runs great on the right, but the left won't fire until you roll on the throttle and then it will backfire.
I have pulled the carb and cleaned it.
Replaced the carb boots.
New ignition coil and new plugs
Swaped plug sides, still not firing.
Checked compression good on both sides, engine will start while checking compression on left, but will not start while checking compression on right.


All out of ideas, any help would be appriciated.
Thanks,
Aaron

Could it be your wire itself? Maybe it's arcing to the engine or frame? Points? Make sure you have a nice juicy fat spark and that it's not intermittent. If you so then it would seem to be carb in nature. It don't take much to fletch a carb up. But I'd check spark first.

After checking for good quality properly timed spark (as already suggested), would also assure valve clearances being to specs (compression test alone is good, but doesn't necessarily guarantee correct valve clearances, and insufficient clearance may result in compression loss upon attaing normal operating temperature).

Would also assure fuel level in float bowl of left side carb isn't too high and causing an excessively rich mixture.

Also assure air filter is clean and unobstructed. If pods are fitted, assure the filter elements are clean and clear, and -- where applicable -- not over-oiled.

Good Luck!

Thanks, for the suggestions! I have narrowed it down to intermitent or no spark on the left side. With a new spark plugs and a new coil. What else would cause no spark?
If points or timing was off wouldn't this mess up the right side spark as well?

Thanks again for the help!
Aaron

You have 2 sets of points. One for each cylinder. Again check plug wires for arcing. Watch at night. Could be plug wire cap too. Process of elimination. GLuck!

Poor spark quality sometimes results from insufficient voltage reaching the coil, which may impair spark on one plug more than the other (because of issues with plug wires or caps, as already mentioned).

There are two terminals on the coil for the primary winding.
One terminal is for positive voltage with ignition switch turned ON (supposed to equal battery voltage).
The other terminal receives the "un-ground" signal from the igniter, which causes the coil to "fire."

Would measure voltage reaching coil at the primary winding terminal(supposed to equal battery voltage).

Might be an issue with the battery or battery cable connection or negative battery cable ground attachment to engine or frame.

Would also measure voltage across battery terminals (look for 12+ volts at idle speed, and 14+ volts at 3000-4000 rpm.)

If the battery and battery connections and charging rate all seem okay, but with reduced voltage actually reaching the coil, it's usually voltage being partially lost through old wiring, faulty connectors, etc. (Where needed, the wiredgeorge coil mod provides a more direct route for voltage from battery to coil with new wiring.)

Regarding possibility of leaking plug wires or plug caps ---
With engine running at night-time in a dark garage, use a common household hand-held water sprayer to mist all over the coil, plug wires amd plug caps. Look for a free fireworks show.

Good Luck!

Here's the ignition as depicted on Kawasaki.com.

[Click on image for larger view]