lost 2 cyl's. help!

I was riding to work 2 weeks ago and half way there my bike started sounding funny.
The bike is a 1992 yamaha secaII xj600
long story short, I checked the exhaust and cyl's 1 and 3 were cold.

Here is what I know so far.
the carbs were professionally cleaned and synced 3 weeks ago.
I rode it for a week (about 250 miles) and then the problem cropped up.

it has spark checked by putting the spark plug against the head and pressing the starter.... strong blue spark

it has compression; checked by putting thumb over spark plug hole while checking for spark.

it has fuel. see above, I got fuel on my thumb while checking compression.

it has air it will run on the 2 cyl's.

the left coil runs cly's 1 and 4
the right coil runs 2 and 3.

here is what I have done for trouble shooting
I checked the fuses with a multi-meter for continuity; all were fine
I checked the coils for continuity they were in spec.
the battery is brand new, three weeks old.
I tried to check the wire harness but all tests failed so I figured out it was operator error .
I SUCK at herding electrons so the electrical is a big jump out of my comfort zone!!
I have replaced the spark plugs (3 times now)

I have done an oil change, its 2nd one since I got the bike.

I have taken the carbs apart and re-cleaned them this last week.

I switched the left coil from the donor bike and that changed nothing.

I have basically spent this week pacing the garage, mumbling to my self, spitting and cursing at the bike.
I am stumped!!!! and I want to ride soooo bad.

can any one offer any advice on fixing this problem.

thanks
slugger

 

here is a pic of the plugs
from left to right cly 1, 2, 3, 4.


and here is what it looks like half torn apart.


slugger

 

If both #-1 -&- #-3 are cold. That's a symptom of you h aving an Ignition Problem.

The 1/3 Coil isn't firing.
Is it the coil?
Maybe ...
Do this:
Unplug the Coils from where they Plug into the Wiring Harness.
Swap the connections.
Plug back in.
If the Problem switches-over to 2 and 4 ... its the Coil.

 

I thought that the coils went 1/4 2/3. If so i don't think it would be a coil problem. But I could be wrong, it's been known to happen once or twice.

 

I have the same bike, and would like to know how this turns out (so if it ever happens to me I can fix it lol).

 

one and four are on the same coil and 2 and 3 are on the second coil.
I will try and switch them and see what happens but I am skeptical since it is one and three that are cold.

I guess I have tried almost everything else so what the heck!

I am almost to the point of trying the open gas cap' flick match,run like HE "double hockey sticks" and call gieco for a replacement. lol

just kidding.

slugger

 

It is 1/4~2/3

I read it wrong.
See if it lights-up one of the dead holes.

 

ok stupid question time
if I switch the coil wiring do I also need to switch the spark plug wires to the other cyl also?

slugger

 

Yes. But you may have a hard time getting the 2/3 wires to reach the 1/4 cylinders.

 

No, no.
When you have a possible dead coil ...
1 and 4 hitting and the 2-3 holes cold ...

You "Swap" ONLY the Coil PLUG-IN's to the Wiring Harness.
IF the Problem switches-over to the 2-3 Holes firing and the 1~4 dead.
The problem is Ignition Related.
Possibly COIL Related.

Just the PLUG-IN's.
Don't try Swapping the Spark Plug Wires, too.

 

thanks rick
I did the wire harness switch and then realised that the plug wires were not going to fit on the wrong cyl's they are too short so I gave it up and switched them back. I will have to go back out and do it again.

slugger