uneven exhaust temps

My 1980 KZ1000E2 is running erratic and the #1 and #2 cylinders are running about 145 degrees and the #3 and #4 cylinders are about 260 degrees when measured at the exhaust pipe near the head. The ignition system is all good. I suspected carb problems so I swapped carbs and got the same result. I don't have that problem with the same carbs on my Z1, so I think I can rule out the carbs. I also swapped out the intake boots to rule out air leaks. Any ideas?

Would assure valve clearances are correct and perform compression test.

Adequate compression is one of the essentials for proper combustion.

Good Luck!

Last night I pulled the exhaust off of my bike, it took about 3 hours begining to end, cleaned and inspeceted the pipes.

My purpose was to replace the copper ghaskets, because I had a leak in the exhaust at the head.

I used white greese to hold the ghaskets in the head until i got the pipes in place.

After i cleaned and completed the job I was happy with the results, much more pressure coming out of the muffler.

So maybe try pulling the pipes and check them out, replace the copper ghaskets $5.00 and see if that makes a difference.

It did on mine.

Matt

try spraying WD40 around the intake boots and anywhere there is a posibility of an air leak, while running at idle.Lissten for a change in sound. i see u tried dif boots and carbs but its worth a try.also as Patton said ,check valve clearance.
how are u checking the temp?

I will re-check the valve adjustment, but it has only been about 500 mile since I adjusted them. I did the WD40 test before I swapped the boots (except I used starting fluid). I guess I should do it again. I think it is possible that I have some kind of exhaust obstruction. I will check everything this weekend and update the post. I used to check exhaust temps with the back of my fingers, but learned that it can hurt and isn't really accurate, so I bought a pyrometer.
I have actually had 3 sets of carbs on it(28mm stock, 28mm smoothbores, and 34mm CV) and got the same results with all of them. If I can get it figured out, I intend to leave the 34's on it.

I have a simular problem in that my left side is a lot hotter than my right.and it seems to take hours to cool off.
I replaced my petcock with a steel flange with a steel nipple welded to it.from that is a brass 90* that goes to the right side where my fuel filter is (so I can check when I'm low on fuel)then back across to a shutoff valve then down to the carb. I think I'm getting vapor lock because the fuel filter runs dry but the tank is full. so I plan to take some left over pipe wrap and make a sleeve to protect the fuel line.
so how do you tell if your air fuel mixture is correct???

jim_palmore wrote:

so how do you tell if your air fuel mixture is correct???

you would check the color on a new spark plug, for each system.
pilot at 1/8th throttle,
needle at mid throttle,
and mains at full throttle.
place tape around the twist throttle and mark off 1/8, 1/2 and full throttle slide openings.
warm up the motor and drive to test area, install 1 new spark plug in each of the 2 cyl's u want to compare.
then u must do a pass through the gears just using the system to be tested(1/8, 1/2, or full throttle). and turn off the ignition, pull in the clutch, stop and remove the plug .replace with a new 1 and repeat for the next system.
then u can do the same on the suspect cyl.

when u get home cut the threaded part off the plug and look for a tan colored ring at the base of the plugs insulator. dark brown, to black = rich. no color = lean.

Why cut the plug???, you can get a inexpensive lighted magnifying glass a 10x is all you need, go toany of the plug mfg sites and they have a section that shows what a proper plug reading should look like and also bad ones listing the conditions that cause the look.
to get the best results, install a new set and go for a ride at speed pull in the clutch and kill the motor, then read the plugs.


mark1122 wrote:

jim_palmore wrote:

so how do you tell if your air fuel mixture is correct???

you would check the color on a new spark plug, for each system.
pilot at 1/8th throttle,
needle at mid throttle,
and mains at full throttle.
place tape around the twist throttle and mark off 1/8, 1/2 and full throttle slide openings.
warm up the motor and drive to test area, install 1 new spark plug in each of the 2 cyl's u want to compare.
then u must do a pass through the gears just using the system to be tested(1/8, 1/2, or full throttle). and turn off the ignition, pull in the clutch, stop and remove the plug .replace with a new 1 and repeat for the next system.
then u can do the same on the suspect cyl.

when u get home cut the threaded part off the plug and look for a tan colored ring at the base of the plugs insulator. dark brown, to black = rich. no color = lean.

I don’t have a light and its easy to cut them.I'm sure a light ,mag would be usefull. Just the way I do it.
U must make sure u only ride on the circuit u want to test. this assures u that u will get an accurate reading of ONLY that circuit, and not a blend of others.