76 KZ 900 / Fouling Plugs

I agree Slmjim. I have an intermittent problem with my KZ1000 ignition...one or maybe two cylinders cut out after riding a few miles. Still chasing it down but I did manage to check voltage at the coils. It was 0.05 volts less than at the battery (12.25 volts) with the ignition on but the bike not running. When I ran the bike it was 9.5 volts. WTF??? Does the ballast resistor dissipate that much power?? The bike has the WG relay setup.

I was not aware the KZ 1000 had a ballast resister. :huh:
Steve

SWest wrote: I was not aware the KZ 1000 had a ballast resister. :huh:
Steve

I think it on the 1979/80 that have factory electronic ignition...

Yes, coils are receiving full voltage (used the wired George relay method)
Valve seals are fine, the plugs are not oil fouled. The plugs are way rich fouled like if you rode 10 miles with the choke on.
Replacing the choke plungers as soon as I receive parts and hopefully will be on the road to recovery.

Installed the new Choke plungers, and reinstalled the carbs ,,,,, back to all stock settings, 17.5 Pilots, 115 mains, NGK B8ES plugs.
Test drove it today about 25 miles and although an improvement , plugs are still carbon fouling soot black (not as bad as before but still not good) Has a stumble around 2,500 RPM. At this point I'm almost out of ideas. I may try a hotter heat range plug and open the idle mixture a little more?
Frustrating to say the least.

Can you post pictures of the plugs... did you do a plug chop test? I’ve had plugs darken up because bike idled in driveway while opening the garage door after a test run

A picture of your plugs would help quite a bit. You say they are soot black, but is it the entire plug that's black and sooty? How does the electrode itself look? Concentrate on it and not the base of the plug for right now.

Rick H.

Before replacing the choke plungers, a new set of plugs would foul within 15 miles to the point of backfires , erratic running, hoping to make it home.
Todays ride , 25 miles was better but still some symptoms of a rich condition, however no back fires etc. . The plugs are fouled dry black soot, no oily content, its like if you ran with the choke on for 15 miles.
Here are some photos of the plugs.

you have carbon fouled plugs... now we need to figure out why... I didnt read or i missed it, do you know if the air corrector jets were installed like Zed1015 mentioned... What are the compression numbers... you didnt mention anything about the carb manifold boots...

Is it possible that the cylinders are that carbon coated also... I remember back in the day the saying was "get that thing out on the highway and clear it out"

Edit: as Zed1015 said unless you plug chop at specific rpms you dont know what circuit is causing the foul.

Edit: Air box is back to stock correct. have you considered the air filter?

You went from a B7ES to a B8ES...
Was there a reason you went one step colder?
got it..you went back to stock settings

Warm the bike up. Shut down. put in clean plugs. Restart and let idle for 10 minutes, no choke, no throttle. shut down and check plugs. If idle circuit is correct, plugs should still be fairly clean, with no black fouling.

Well! The results with the new plungers certainly shows the effect that worn seats have on running and the benefits of fitting new ones or having them re-seated but you are still too rich which should not be the case on the stock jetting.
If the mixture screws are correctly set etc there has to be something else going on such as restriction of the intake or flooding.
As i already mentioned, with pods previously being fitted are there any air corrector jets in the mouth of the carb ?
Also some pattern float needles have been shown to be too short and don't shut off the fuel causing the same symptoms.
And what about the air box or filter . Any restriction there will cause the engine to pull excess fuel.
Some people have had problems with some Keyster kits and although i have found them to be accurate there's talk that there's some fakes on the market so maybe reverting back to the original Mikuni items could solve the issue.