Black spark plugs

I have a 1978 KZ1000 ltd with 15,000 mi on it,when i bought it the carbs were all gummed up,i'm a pretty good wrench and i did every thing right in my book but am haveing trouble with the plugs black with soot after only about 3 miles.Here is what i have; stock carbs with stock pipes that ahave no baffles(i like noise)120 main jets, 15 pilot jets, stock needles on the middle notch,all carbs cleaned, bead blasted exteriors, floats set to specs,all passages seem clean and clear!! Did the add a relay to the coil system for full power to the coils, new NGK resistor type plug wire ends,compression test 95-105lbs accross the board. # 1,2&4 are sooting and #3 is perfect, all settings on the carbs seem equal. What the heck am i doing wrong???If any one has an idea i'll be glad to listen. THANKS JEFF

jeffff wrote:

I have a 1978 KZ1000 ltd with 15,000 mi on it,when i bought it the carbs were all gummed up,i'm a pretty good wrench and i did every thing right in my book but am haveing trouble with the plugs black with soot after only about 3 miles.Here is what i have; stock carbs with stock pipes that ahave no baffles(i like noise)120 main jets, 15 pilot jets, stock needles on the middle notch,all carbs cleaned, bead blasted exteriors, floats set to specs,all passages seem clean and clear!! Did the add a relay to the coil system for full power to the coils, new NGK resistor type plug wire ends,compression test 95-105lbs accross the board. # 1,2&4 are sooting and #3 is perfect, all settings on the carbs seem equal. What the heck am i doing wrong???If any one has an idea i'll be glad to listen. THANKS JEFF

Thanks for all the good info , and could use a little more.

floats set to specs -- is this verified with clear tube test?

What air filtration system is fitted -- Air box? Pods?

Are valve clearances within specs?

Good Luck!

duplicate thread. Should merge with the other one in engine section.

yes with clear tube,seperate air filter pods, valves reasonably close

i'm sorry i have no idea what your trying to tell me by duplicate thread or the rest. Please clarify. THANKS

Here is a quick test. Switch the wires between 2 +3 and see if it changes anything. If it does it could be a ignition wire problem.Coils or wire could be breaking down.

i'll try it , thank you, jeff

Some thoughts ---

Are pods breathing clearly? Not over-oiled?

If doubt, could test run without pods.

Proper NGKB8ES sparkplugs, gapped to specs?


Good Luck!

Have spark plugs been removed and visibly examined for fat blue spark?

Has function of automatic advancer been verified with strobe type timing light to assure it's freely and instantly moving back and forth with changes in rpm by blipping the throttle? Wanting to assure the advancer isn't stuck or hanging or otherwise malfunctioning.

Good Luck!

i'll check, thank you, jeff

jeffff wrote:

i'm sorry i have no idea what your trying to tell me by duplicate thread or the rest. Please clarify. THANKS

The post in ENGINE section labeled:

BLACK SOOTY PLUGS

I have a 1978 KZ1000 ltd with 15,000 mi on it,when i bought it the carbs were all gummed up,i'm a pretty good wrench and i did every thing right in my book but am haveing trouble with the plugs black with soot after only about 3 miles.Here is what i have; stock carbs with stock pipes that ahave no baffles(i like noise)120 main jets, 15 pilot jets, stock needles on the middle notch,all carbs cleaned, bead blasted exteriors, floats set to specs,all passages seem clean and clear!! Did the add a relay to the coil system for full power to the coils, new NGK resistor type plug wire ends,compression test 95-105lbs accross the board. # 1,2&4 are sooting and #3 is perfect, all settings on the carbs seem equal. What the heck am i doing wrong???If any one has an idea i'll be glad to listen. THANKS JEFF

That's a duplicate of this thread.

The main jet sounds big for a mostly stock engine, especially with only 100psi compression.