77 KZ 750 B

bgulsvig wrote:

I tried adjusting the pilot screws but that seemed to have little affect on things. I did notice a difference in pressure coming from the mufflers. You mention the balance adjuster screw but I can't reach it while the bike is running.......

(To do it on the bike. You have to remove the tank and have a sperate bench tank, or long hose on your tank, to supply fuel to do it on the bike.. they (kawasaki) sell a special tool for use on the balancer screw. Myself years ago I found old tool that came from something else which I use. Basically though you just need something that will allow you to loosen and tighten the lock nut, while you turn the screw with a long flat screwdriver and relock the nut while holding the screw in position.) I dunno, perhaps a socket welded to a piece of hollow tube with a small handle welded to the tube, so you can insert the screwdriver into the middle of it, unlock/lock the nut, while holding screw still.

It's more work, but the bench setup usually works fine. It's just a matter of partially or completely removing the carbs. For the sake of undoing the throttle cables I recommend completely removing them so you can just set the carbs on your bench. If you're not comfortable with removing the cables just get an assistant to hold the carbs for you at the side of the bike. Unlike inline 4s your carbs come off easily, two bolts on the sides of the air box allow it to push back far enough to get the venturi stacks off easily.

Anyway here's the method I use.
Turn the idling screw in until the butterfly valves begin to open and there is a gap between the valve and the bottom of the bore you can see. Loosen the locknut on the balancer and adjust the screw until you have as close to the same gap as you can get on both carbs by sight. Holding the screw with your screwdriver, lightly retighten the locknut with a wrench. I've seen many with locktite on them, but I've never used it and have never had one come loose.

To go beyond this visual.

Stand the carbs so they're pretty level, or sucker a friend into holding them for you. Get yourself a piece of straight solid wire and cut yourself two pieces an inch long or so. Really, anything you have at hand that will give you two pieces and is round so it will roll to the very bottom of the bores. Two small pieces of small diameter round stock work.

Use the idle screw to open the butterflies enough so you can lay the pieces of wire in the very bottom of the bores of both carbs. Now slowly back off the idle screw while watching the butterflies and see if one contacts a wire before the other. If so, readjust your balancer screw until both touch simultaneously. Just slightly touching btw, any force will mess it up, you just want it to touch.

Once they're both touching at the same time you're about as close as you can get on the bench, and I've check with vacuum gauges afterwards and they were within factory spec. Turn down the idle screw a bit so your bike isn't idling insanely when you start it.. course you'll still have to adjust the idle later. DON'T forget to remove the wires.. LOL.. bad if you don't I'm thinking. :silly:

You have the old carbs so you may need to back off the lever stop screw if it's maladjusted. Usually though I'm using a thick enough diameter wire that it isn't a factor.

On another note, I forget wether you mentioned it before (forgive me if you did) but have you checked your timing advancer for free movement, and both springs in place. The way the bike is acting it's one of the first things I'd have checked.

bgulsvig wrote:

I have had the carbs off and cleaned/air pressured them many times. How could the pilot curcuit be plugged.
I tried observing the spark last night looking for the "fat blue spark" but I couldn't tell as it was arching in two or three spots on the electrode.........

Crud may resist carb cleaner and air pressure, whereby physical assistance becomes necessary, such as a small guitar E string.

The choke issue could result from clogged pilot air passage. Or overly aggressive cleaning may have reamed the pilot jet resulting in an over-rich pilot circuit. Or perhaps the pilot screw tip and/or seat is damaged whereby adjustment is inconsequential.

The choke issue suggests a carb problem, regardless of reported immaculate cleanliness inside.

It's immaterial about where the sparks are jumping between electrodes. Each spark should be fat blue, and not weak orange. Fat blue suggests basically okay subject to proper timing and functioning advancer. Weak orange spark indicates something is wrong somewhere.

Meanwhile --- What's voltage measured across the battery terminals, and measured at the coil? As such info is needed for further diagnosis.

Good Fortune!

I tried starting it last night but would not fire. I looked at the spark from both plugs grounded against the head and they looked weak and intermittent. I switched the spark plugs and had different results. Can a bad coil make the plugs go bad? They were brand new plugs.I will try another set of new plugs tonight. I was going to check the voltage at the coil but I drained the battery trying to start it.

I was tinkering with it last night and tried to adjust the carbs. I let it idle for a full ten minutes. During that time I tried different settings of the pilot screws. At one point I had them both screwed all the way in and seated. There was no change in idle speed. Is this normal? I tried one, two, even three turns out with no change in RPM'S. Would this suggest the pilot passage problem? I again pulled the plugs and found one normal and one completely black

I checked the voltage at the battery....13.07 volts
I checked the voltage at the coil .....10.60 volts
Does that mean the coil is bad or do I just need the
"coil mod"?.....

bgulsvig wrote:

I checked the voltage at the battery....13.07 volts
I checked the voltage at the coil .....10.60 volts
Does that mean the coil is bad or do I just need the
"coil mod"?.....

Does not mean coil is bad.

Best remedy imo would be to find where voltage is being lost and fix it. See image below.

Loss may be at one or more connectors, at ignition switch, at on-off kill switch, at fuse connections, etc.
And often results from corrosion.

Good Fortune!

[Click on image to enlarge view.]

How exactly do I do the "coil power mod"?....any pictures?...

bgulsvig wrote:

How exactly do I do the "coil power mod"?....any pictures?...

Put the softest part of your body in a large bench vice. Have a buddy tighten the vice until blood squirts. Have said buddy take pics to post here. Now, every time you think you need the coil mod instead of actually fixing the problem, you can visit the forum and look at your pics.
:ohmy: :ohmy: :ohmy: :ohmy: :ohmy: :ohmy:

On the other hand, you could carefully clean the various connectors with a quality electrical cleaner. While doing this, you can look for and repair any breaks or potential breaks in the wires. Once this is done, there's a good chance that proper, reliable voltage will be reaching the coils.

bgulsvig wrote:

How exactly do I do the "coil power mod"?....any pictures?...

Several similar variations.

Here's one way:

Click > www.wgcarbs.com//index.php?option=com_co...view&id=12&Itemid=26

Coil mod creates an additional path for voltage from the battery to the ignition coils.

It does not correct whatever shortcomings are causing the voltage loss in the first place.

In other words, it doesn't cure the problem, but just goes around the problem.

Treats the symptom without curing the disease.

Good Fortune!

TexasKZ wrote:

...Put the softest part of your body in a large bench vice. Have a buddy tighten the vice until blood squirts. Have said buddy take pics to post here. Now, every time you think you need the coil mod instead of actually fixing the problem, you can visit the forum and look at your pics...On the other hand, you could carefully clean the various connectors with a quality electrical cleaner. While doing this, you can look for and repair any breaks or potential breaks in the wires. Once this is done, there's a good chance that proper, reliable voltage will be reaching the coils.

:laugh: :laugh: :laugh:

So either apply a tourniquet (coil mod) or remove body from vise (fix the underlying problem).

Good Fortune!

Don't be intimidated by the electrical diagram.

Could start by measuring voltage coming out of the 20 amp fuse connection.

The fuse clips may be corroded and disallowing full voltage through the fuse.

Good Fortune!

Voltage is 13 at the battery, 13 at the fuse, 13 at the connector in the head light, and 11.5 at the ingition switch and kill switch. None of the wires or connectors are corroded. They are like brand new?.....