Spark Plug: Overheating on a Colder Plug?

The plug tips on my '81 KZ440 are coming out pure white (picture would not upload) all the way to the 90 degree bend on the tip. This is after about 20 minutes of warm up and trying to balance the carbs, and then about 5 minutes of riding; otherwise these plugs are brand new.

My understanding of this means that it is running too hot, usually indicating a lean condition. These plugs are NGK BR9ES, which is different than the factory recommendation of B7ES. Given that the B7 is a hotter plug, would the B7 come out even more white/overheated, or would it get better since it is a hotter plug? Perhaps this isn't even a spark plug issue, maybe I'm just not balancing the carbs perfectly so they're running lean. I'm not sure how to interpret this.

how many turns out is your air screws?
2 carbs easy try 4 of them bitches!
hope you have a fan on this motor when servicing it?

If you are referring to the idle mixture screw, they are 2 1/4 turns out as specified in the manual. However, the 440 does not have an air screws - the only adjusters on these keihn carbs are the balance screw, idle mixture (factory preset & plugged), idle stop, and float height. The only live adjustments I can make are to the balance screw and the idle stop.

The fan might be a good idea. Is it possible it's getting too hot from just sitting there and being revved up?

yes sir it is

are you using a sync tool?

I probably should, but I don't have one. Are there cheap ones out there that you would recommend?

About the plugs, do you think changing to the factory recommended plug would make a difference even though it's a hotter plug? I've been going with the BR9ES just because that's what came with the bike.

If you let the bike sit and idle for 20 minutes it very likely was overheating causing the plugs to turn white. These engines are air-cooled and should not sit and idle for more than just a couple minutes without a fan blowing cooling air on the engine. 20 minutes is a looong time for an air-cooled bike to run without moving. You may want to install new plugs and go for a long ride to see if the plugs look normal. Ed

Oh for goodness sake.
The only way to read a spark plug is at FULL THROTTLE UNDER FULL LOAD !!!!!!
For ALL the other adjustments you just use your ear and the seat of your pants.

And use the standard plugs unless the engine is HIGHLY modified AND you know what you are doing.

Good news and bad news.

The good news - I got it running acceptable; it can pretty easily maintain 65-70 mph in a strong headwind with the throttle not more than a 1/4 open, so in my book that's running pretty good.

The bad news - I seem to have to replace/clean the spark plugs every time I run it. After going on a lengthy ride yesterday, I started it up today and it sounded really weak. The idle got slower and slower even with the choke on (it would stall with the choke off). Eventually it stalled out and wouldn't start again. I pulled the plugs and they were entirely black and had gas on them. I Replaced the plugs with a previous set that I had cleaned and it fired right up and was back to running acceptable again. This is the second time this has happened; it runs good one day, then the next day it barely runs at all.

Am I still running lean and burning out the plugs? Any ideas?

P.S. Thanks for the tips above. I think the fan made a difference in keeping the bike cool during the tune up.

Find non resistive sparkplugs(the "R" in the plug number). I'd imagine your bike has the standard sparkplug caps? if so, there's already a built in, non serviceable 5000 ohm reisitor inside the cap. So now you've got two resistances, reducing the spark energy,making tuning more difficult for yourself.

Austin440 wrote: Good news and bad news.

The good news - I got it running acceptable; it can pretty easily maintain 65-70 mph in a strong headwind with the throttle not more than a 1/4 open, so in my book that's running pretty good.

The bad news - I seem to have to replace/clean the spark plugs every time I run it. After going on a lengthy ride yesterday, I started it up today and it sounded really weak. The idle got slower and slower even with the choke on (it would stall with the choke off). Eventually it stalled out and wouldn't start again. I pulled the plugs and they were entirely black and had gas on them. I Replaced the plugs with a previous set that I had cleaned and it fired right up and was back to running acceptable again. This is the second time this has happened; it runs good one day, then the next day it barely runs at all.

Am I still running lean and burning out the plugs? Any ideas?

P.S. Thanks for the tips above. I think the fan made a difference in keeping the bike cool during the tune up.

You mentioned that after a ride you pulled the plugs and they were entirely black and had gas on them. This would indicate that either the plugs are too cold or the air/fuel mixture is too rich. In an earlier post you stated you are using BR9ES plugs. Those plugs are 2 heat ranges colder than the plugs called for by Kawasaki (and are resistor type plugs which doesn't help), so it is likely that this is contributing to the plug fouling problem. I suggest you install the spark plugs that Kawasaki recommends - they are B7ES plugs (see diagram). This should help eliminate the plug fouling problem. Ed