From The Top.

When I first came on the forum I was looking for help getting my 1977 KZ1000 11,600 mile running like it should.
I was only getting 20 mile out of a set of plugs (black, sooty and fouled) except#2 this looked good.

My first thought was doing the "coil mod" but through the advice here it was decided against. "Most" everyone suggested that I just find the problem and fix it! I couldn't agree more. So in the attempt to find the problem this is what I have done to this point.
1)New Battery
2)New air filter
3)New Dyna S -installed and timed
4)New Dyna coils the green ones
5)New 8mm wires
6)New Denso Plugs
7)Cleaned every connection I could find (twice) steel wool, and electric cleaner 12.5 across the battery/13.5 running 4,000 rpms. Had 11.7 to the coils but now 10.4v
8)Took apart and cleaned the kill switch.
9)Took off the ignition switch cleaned what I could see which was bacislly the connection on the back, sprayed cleaner inside.
10)Took off the carbs, sprayed cleaner through all the pilots, missed the air pilot but spray shoot out the side when I sprayed thought the main so I'm sure thier clear. Bench sync, and adjust the floats to the min level except #2 (clear tube).

After all this it still has the same issue. So I'm thinking of doing to coil mod "JUST" to see if the issue is electrical. If the plugs clear up then I would know it's not a carbs or valve issue and that I have to go through the elecric system again. GIVE ME YOUR THOUGHS ON THIS.

Recently(last few days)here, a member mentioned his richness plungers/choke were worn/sticking on his carbs making the sparkplugs run rich/turning black.

I'd look at this as you appear to have checked everthing else.

Yes, do the coil mod! It works as advertised to ensure that the coils get full battery voltage every time.

ken wrote:

7)Cleaned every connection I could find (twice) steel wool, and electric cleaner 12.5 across the battery/13.5 running 4,000 rpms. Had 11.7 to the coils but now 10.4v

? :huh: ? With the bike running or not, the voltage at the coils should be what the voltage across the battery is. Period.

If not than you have deffinately missed some critical connections, or, you need to start replacing wiring.

The coil mod will solve the issue with the voltage to the coils and get you riding, but it will still require some work to get your bike up to reliable condition.

Its a good thing that you've replaced all that old aging ignition, but the fact that you have 3 black plugs and 1 nice white one says deffinately a carburetion issue to me.
If your pulling the plugs after the bike has idled for more the a couple seconds, all your seeing is the idle circuit/mixture screws effect. This tells you nothing of what the bike is doing under throttle.

The best thing to do is replace the pilot jets (they're so hard to get perfectly clean), and make sure you hav absolutely no air leaks.

You MUST properly manometer vacuum balance your carbs, or its all just a crapshoot.

GL!

MFolks wrote:

Recently(last few days)here, a member mentioned his richness plungers/choke were worn/sticking on his carbs making the sparkplugs run rich/turning black.

I'd look at this as you appear to have checked everthing else.

I forgot to list this one. I checked each one and they all seem to being going down all the way.

Why not just measure the voltage drop from the battery to the coils? That will tell you in a few seconds if you have a voltage issue at the coil's positive terminal.

While idling, and then reviing, measure the voltage with black meter lead on the coil's positive connection, and the red meter lead on the battery's positive connection. The meter will directly measure the voltage drop. Ideally, this measurement will be less than 1/2 a volt. If it's much more than 1, then there's definitely a problem.

Well I got some emery cloth and went though all the connections for a third time. Adjusted all the bottom carbs screws (except #2) to 1/2 turn out. Went for a 30 mile ride and the plugs did not foul!! #2 still looked almost new while the others were somewhat brown. Now this is a big change from the black,sooty and fouled I've been getting. I'll go for a longer ride tommorow and keep my fingers cross the problem is solved.

When tuning an engine, I go by these colors:

BLACK:too rich, could be dirty air filter,low input voltage to the ignition coil(s) or possible coil/sparkplug cap breakdown.

WHITE:too lean,air or vacuum leak before or after the carb,possible to high of a heat range for the sparkplug(s).

LIGHT TAN:just about right for optimum combustion.

The next time you go through the many and various electrical connectors/switches, use some very good electrical contact cleaner/preservative called "De-oxit" made by Caig Labs in San Diego Ca. www.deoxit.com is their website.

It can be purchased at Radio Shack stores in the U.S. and other electronic supply stores.

I use it on all of the switches and electrical connectors/fuse clips on my bike along with electrical items in my house such as cordless phone charging cradles, the battery contacts on the TV remotes and all patch cords for the entertainment center.

The best thing here is that I've gotten this far and no coil mod! I have a few new tools, and a few new friends. I know alot more about the bike than I did three weeks ago. I really hope the problem is solved. Still need to syn the carbs yet tho.

Congrats... feels damn good don't it!
You had some issues, sure you struggled & got frustrated but you stuck with it, you fixed it correctly, you learned a whole slew of shiza on your KZ and she's running as designed for optimal performance...

Get the carbs synced and she'll run even better...

Life is good...

Tip: Now that she's electrically tight... Run through the electrical tests (All of them) and record your measurements for future t-shooting if & when required!

LUV happy ending stories like this, way to stick with it...

OMR

another thing to keep in mind also because everything isn't electrical you may have weakfloat valve needles and worn seats. usually when its occuring on different cylinders it will be fuel related or possibly even plug cap.