OK guys.... I've had some problems... my left cylinder was black (the plug) and my right cylinder was white (again... the plug).  I will describe what I've done today in order of how it was done... and the "progress" i've made and list below it all of the things I did prior to today!

1.  I cleaned up several electrical connections (including the aux. ground... its in good shape now)
2.  I took out the plugs and turned down the mixture screw on the left plug
3.  I started the bike on only the left cylinder (had the right plug out) and adjusted the idle and mixture screws for the millionth time
4.  The bike idled well on only the left cylinder and after several minutes of running at a good operating temp... The plug showed no coloration... the plug wasn't white, tan, or black... it was just metal... but it idled and ran well on only the left one.
5.  I tried to start the bike on the right cylinder only (with the left plug out) but wasn't getting spark from the plug (a new plug... and I tried the plug from the left cylinder).
6.  Put a different coil (i had another set... it was labled F2) on the right side and had great spark.
7.  Adjusted the idle and fuel mixture screws until it idled well and took on a tan color.... (it ran for several minutes again)
8.  Noticed a HUGE amount of fuel/air pumping out of the left cylinder as the right was running... but it had run correctly just 5 minutes ago so I ignored it
8.  Thought I had solved my problems... then I plugged both plugs in and  tried to ride
9.  It was running on only one cylinder again (the right one this time)
10.  I checked for spark on several plugs and noticed that now THERE WAS NO SPARK FROM THE LEFT SIDE!!!!
11.  I QUIT IN FURRY!!!

My starter relay is pretty rusted on the outside... my thinking would be that if it was bad, however, that it would not even try to turn over.... if this might be a problem please let me know.... on with the post...

Any ideas why this would happen?  The following is what I have already done to try to remedy the problem:

-Sync'ed the carbs
-rebuilt the carbs (new float needle and valve, new mains [127.5] & pilots [40], 1 washer, all new o-rings [cept the one under the slide supports] and bowl gaskets.
-Cleaned the carbs
-New intake manifolds
-New exhaust gaskets (metal piece)
-Replaced the signal generator
-Replaced the cdi box
-adjusted the float height according to kerry's test
-have the idle mixture screw turned to 2.5 turns out
-choke plungers SEEM to be sealing ok... nothing is stuck and I dont have a choke cable so its not snagged
-replaced the gas (thought maybe some freak thing with bad gas)
-Checked for pinholes or tears in the diaphragms visually... (I didn't find any by feeling and looking at them)
-lightly lubricated the slides
-no bends in the needles that go through the middle of the slides
-Replaced coils and wires
-Rebuilt head (all valves and seals)


All help would be so greatly appreciated!!!

Sell all those parts that you bought, and buy a new bike! 

Sorry dude, I'm stumped too!

oh wow man... do you have a good multimeter?  Try checking the wiring harness with the continuity(sp?) tester (the setting that beeps or makes the needle jump up when you touch the two wires together).  For each wire (yeah this may take a while) stick a probe from the multimeter into each end (heh this sounds naughty) and make sure it beeps.  Try wiggling the wire harnesses to make sure it continues to beep as you wiggle it.  If something doesn't beep or beeps/doesn't beep when you wiggle it, pull the harness apart and make sure the crimp connections are good.  It is possible the strands in a wire, usually somewhere near the end, are broken while the shielding is not.  This will make the wire look fine when it's really not.  The first wire I'd check would be that secondary ground wire coming from the battery that goes to that connector, check before and after that connector.

have you checked compression?  Either go to walmart and buy a compression tester for $20, or borrow one from a good autoparts store, and check the compression on each cylinder. 

This is all I can think of.  The broken wire idea is a good possibility, I've seen it happen before on a car and boy is it a Buddha Loves You to find.  I hope this helps!

Looks like you have tried just about everything apart from the possability of a broken wire, a friend had the same problem that turned out to be a broken wire, and we only found it by pure accident, as we pulled the wire to join it and it just snapped, we couldnt see the break because of the sheathing, it was a black earth wire located under the seat, your only other option is to try and source a decent wiring loom if all else fails, but you can not be sure that thats OK, but the thing is with second hand items, you can not be sure that the ones you have replaced were in good working order, as with many people I would have went for, pulse generator coils, ignition coils or related wiring to them

hope you get sorted soon, before it drives you insain

i'll keep trying... thanx guys....

p.s.... i just redid the 2ndary ground

Maybe try this :

1. Engine ignition timing out of adjustment
2. Open or short in high-tension cords

I hope it can help you!

NGK plugs right ... they are fooked ... replace them with champion 809's I think. I know I know lawn mower plug ... yes replace it anyway ...
Cool.
Srinath.

Really? lawn mower plugs are better than the NKG ones?

Cool, I'll keep that in mind for my next plug change!....  Or is it a significant change that I should change them now?

Quote from: KYGS500E on April 24, 2006, 04:44:07 PM
8.  Thought I had solved my problems... then I plugged both plugs in and  tried to ride
9.  It was running on only one cylinder again (the right one this time)
10.  I checked for spark on several plugs and noticed that now THERE WAS NO SPARK FROM THE LEFT SIDE!!!!
11.  I QUIT IN FURY!!!

The fact that spark changed sides leads me to believe that common wires to both sides, that are next to each other, have chafed and are shorting between each other.  Trace the wires from the coils to the harness to see if they ever get close to each other.  Also, check from the harness to the ignition pickups (or, from the pickups to the harness).

Where did you get your signal generator from?

bought it from alphafire