1980 KZ 1300 Spitting problem

Hey guys,I got a question about my 1980 KZ 1300. I just recently acquired it and not being familiar with these engines I farmed out the tune up and carburetor(s) rebuild to a shop that has KZ1300 experience. The motor spits through the exhaust pipes on the right hand side and slightly misses. Starts good but with the miss and starts spitting soon afterwards. To me it sounds like the valves may need adjusting to correct the problem or the carbs are not quite tuned. Not sure which. The mechanic has tuned and re-tuned the carbs in an attempt to eliminate the spitting and miss without much success. The spitting seems to be getting worse. Also he checked out the ignition and ruled out any problems there. So I am thinking valve adjustment is in order to fix the problem. I just want you guys to give an opinion and see if I am missing any other conditions that may be causing this. Below is a breakdown of what was done to the KZ.

1.General tune up including new plugs
2.oil/filter change
3.Carbs stripped, sonic cleaned and a Stage One kit installed.
4.Bad Stator replaced – charges at 13.8 volts.
5.Ignition wiring/coils inspected and tested – within specs.

Note: Bike came with Accel coils and pods installed.

Hopefully this is something easily solved and fixed. …. Any Suggestions?

What condition are the carb boots in? Any cracks or possible air leaks?

The boots checked out good.

I tuned one up that had no clearance at the valves. That took alot of shims! I went through the carbs too and in the end it ran great except the left hand cylinder wouldnt kick in until the rpm got to around 1500. That cylinder had only 90psi but would go up high when oil was added to the cylinder. Spitting tells me misfire, or lean misfire. I'd check the compression, check the plug wires at night for arching. Check the deccel pop off diaphram for tears or sticking. Those passages need to be clean as well. Look closely at the plug for color. Is it wet? Dry? Is it even a real spark plug? If you can't locate the miss through these tests, try a very small gap at the plug and see if it spits then. That will reduce resistance and the possiblility of a misfire under load. Check that coil over good, it's very hot under the tank. You can hear the fuel boiling in the tank on hot days that's how hot it gets. Nother thing to try is holding your hand over the carb and slowely block the opening, listening for the miss to change. That should tell you if it's fuel related since it would be getting enough gas to that clinder. On that bike be careful with the timing chain tensioner they are weak and junky. Make sure the chain is tight and the tensioner isn't coming apart on the end. Might want to get out a cordless for the valve cover bolts there's about 460 of them. Keep in mind the float level in case it comes into play. If you tip the bike back and fourth while it's running and the miss changes.... :woohoo:

These bikes are notorious for burning up ignition coils. I would check those. The pick up coils are also known to go bad on them. I also noticed that you have a stage one kit on the carbs. I am not sure I would trust it.

How many Ohm coils are the Accel. The ignition system on this bike is a 3 Ohm system. Is the ballast resistor still installed? Dependent on the resistance of the Accel coils you may have to remove it if it is. Who overhauled the carburetors?

Sorry guys, I ve been out with a killer toothache and not feeling up to snuff. To bring you up to date on the old KZ1300, I put her back in the shop yesterday when she wouldn't start. Come to find out, the battery is dying with one cell not charging as it should and the other cells trying to take up the slack. Not sure if this has anything to do with the spitting problem but the mechanic seems to think the bike's electrical system was taxed trying to charge a dying battery and not supplying enough juice to operate the ignition system. In other words, a weak spark from a degraded battery. Sounds logical but we'll see in a day or two. Thanks guys for your input I have followed your suggestions and so far it all checks out OK except for the Battery problem. After this is fixed I'll go from there if the spitting continues.

unomike wrote:

Sorry guys, I ve been out with a killer toothache and not feeling up to snuff.

Sorry to hear man, I know how that feels.

Battery being bad... Not sure if this has anything to do with the spitting

Which it doesn't...

mechanic seems to think the bike's electrical system was taxed trying to charge a dying battery and not supplying enough juice to operate the ignition system.

Time to go to another mechanic Sorry if he's a friend. :dry:

In other words, a weak spark from a degraded battery.

Nope... If your stator/rectifier/regulator was dropping 13.8 into the battery, then thats what your coils were getting... unless the wiring is toast. Battery just acts like a big capacitor once bike is running.

I'm not sure what you mean by spitting out the exhaust? Do you mean that its making a loud clacking noise out the exhaust flange while running? Or its spitting out the end of the exhaust pipe, like fuel?

While running, are all the cylinders firing? Check by tapping (VERY QUICKLY) at the 2nd bend in the exhausts for each cylinder. They will be very hot, just shortly after running if all is at least OK. Water will sizzle off each one, if thier at least reaching proper operating temp.

Spitting may or may not have something to do with the valves... the gaps should be checked regardless, as this is considered part of the regular maintenence of that bike.

Hope this turns out helpful.

Cheers, good luck!

Well, it has a new stator putting out 13.8 Volts to the battery. Has a dead cell so new battery is going on it in the morning. I have had bad batteries cause poor performance in some machines but that was combines with grounding problems too. And like I mentioned in my previous post, I DO believe that the valves need adjusting and that should be addressed by the mechanic after he rechecks his work ... again.

OK, to describe the "spitting" through the exhaust. .. I think the sound is like a valve closing a little late on the compression stroke. I cannot describe the actual sound other than a spit at idle. When the engine is rev'ed up it goes away, or at least masked by the increased exhaust noise. Anyways, I'll know more about it in the morning.

OK cool. Let us know...

I have had bent valves on mine before. These are a very rare engine on bikes. In that they are "long stroke", this makes them prone to piston strikes. The 13 is the only bike that I ever managed to bend a valve on. The other thing that can make a sound like that is if the inrichening valve on the carburetor is bad. They ware very quickly.

I finally got around to posting some pictures of my 1980 KZ1300. This is the bike just after I got it.