backfiring.. no start.. ignition timing?

Hello, i still havent solved my bike... I cleaned all my electrical contacts and bought new coils. Each plug has spark. Now when the bike turns over, it backfires out the carbs. it sounds like it wants to go, but still no luck. I have a dyna ignition.. is it timed improperly still? i could use some help. Also for every 10 times the carb backfires, a big boom comes from the exhaust as well. \please help.. I just want to go for a ride!

Once you get those hoses either hooked up or plugged off, then check to see if you have the coil wires on correctly. One coil for the two outside plugs, and 1 coil for the two inside plugs. That is if its a four cylinder. Then if still not right you may have the smaller primary wires for the coils mixed up. You can swap them, and leave the plug wires. Your book will show you the wire colors and which coil was the factory hook up. But with the aftermarket Dyna, they could have reversed this.

The first portion covers the Z1's,Kz900's,Kz1000's & Kz1100's. The lower section touches on the 550's,650's, & 750's as the coils are wired diffently.

Ignition Coil Primary And Secondary Wiring

Ignition coils on the 80’s Kz1000,Kz1100’s and Gpz1100’s are wired the same, that is as you sit on the bike, the LEFT ignition coil primary(small wires) are two wires, RED and BLACK. The secondary (or sparkplug wires) go to #1 and #4 sparkplugs(your primary wiring may be different).

The cylinders are numbered left to right as you sit on the seat; #1,#2,#3, and #4.

For the RIGHT ignition coil, the primary wires, again are two wires, RED and GREEN, with the secondary going to #2 and #3.

The RED wire gets it’s voltage from the run/stop switch on the right handlebar switch pod.

The BLACK and GREEN wires connect to the IC Igniter(if the bike has the Kawasaki supplied electronic ignition) it actually gives the coils their grounds to fire the sparkplugs.

Primary(small wires) side of the coils will read between 1.8 to 3.0 ohms.

Secondary(sparkplug wire ports)side of the coil will read between 10.4K to 15.6K ohms. These ports are wired together, so it makes no difference which is used, as long as the correct coil to sparkplug configuration is followed.

The sparkplug caps should read 5K OHMS, any higher, or a reading of infinity means new caps should be ordered.

To stress the ignition coils, take a hair dryer, heat the coils and see if the ohm readings change from cold to hot . If they do, it’s time to buy new coils.

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Keep in mind, the wiring is reversed for the 550’s 650‘s and 750‘s, that is the RIGHT coil primary will be two wires, RED and BLACK with the secondary(sparkplugs) going to #1 and #4.

The LEFT coils primary wiring would be again two wires, RED and GREEN, with the secondary(sparkplugs) going to #2 and #3.

These engines have what is known as a “Wasted Spark” that is, a sparkplug will fire during an exhaust stroke. It does no damage and many other motorcycle engines have this design.

hmmm, I checked the spark on all cylinders.. my left coil is sparking cylinders 2&3 at the f timing mark for 2,3 and the 1&4 cylinders are firing at the f mark for 1,4... it seems timing is not the issue. Any other ideas?

I just looked back and saw you had the motor apart. Has it run since? Have you checked compression?

i did have the motor apart, hasnt started since.. But i changed the piston rings on two of the pistons... I was hoping that was the least of my concern.. I suppose i'll make another trip to canadian tire and purchase a compression tester.

Do you have a manual, and did you follow the sequence for installing the camshafts? I suspect that you may have installed the camshafts wrong. Hopefully you haven't bent any valves.

I hope so too. I followed the directions as the manual stated. TDC 33 links and whatever. I even turned the engine over slowly a few times with a socket driver to make sure there was no resistance

That was one of the questions in my head. That's great. Try with the plugs out and Ignition off, seeing if when Kicking/ or cranking, if it will blow your finger off of the plug hole. Did you disassemble the head when it was apart? Check the valve clearance?

The valves were shimmed by the previous owner, but when i took the engine apart it is possible the the little valve covers fell off a few of the valves and the shims may have been swapped.. I will have to buy some feeler gauges tomorrow and check. I will also check the pressure coming from the cylinder. I will give a further update tomorrow.

Thanks very much for all the help

While you're in there double check the cam timing, if you have to re-shim then the cams would have to come back out. You have what model again? A shim under bucket/ cam follower right?
Kz ? Add your bike to your signature, so we call all see what the bike is when responding.

Well ive finally reached the problem. After replacing cylinder's 1&3 rings this winter, of course cylinder 2 has no compression... looks like i get to wait another couple weeks for more parts..... sigh. Thanks for the help though. Better to know the problem than never fixing the bike at all.
ps its a 1977 kz650. you must not have seen my sig.