82 550m still not starting....

[triple6cafe]

I posted this question a while back and im back again, got a lot of good ideas of where to start and Im back with the results, well lack of
First a real quick description of the problem....
The bike simply will not start, it just spins and spins until the battery runs out of juice or I give up (a burnt out starter is the last thing I want). Using starting fluid or even trying to "jump" start it by putting a little gas directly in the cylinders does nothing, I dont even get a backfire.
Whats been checked
Carbs have been gone through/rebuilt and reset to factory specs. Battery is new and fully charged. New NGKs.
Now to the new stuff, was running compression checks on it today and when I cranked it with the #1 plug out it actually tried to fire!! Did the same thing when I tested #2 etc. I could smell exhaust, the tach was reading it wanted to start!! After about 15min of it consistantly doing this, I hook the plugs back up put the tank on, prime it go crank it and nothing it just goes back to it old routine of cranking and cranking.
So...
I did the ignitor box test (hooked to the bottom of the airbox) as the clymer tells you to, and I could only get #4 plug to spark #3 wouldnt which according to the clymer means the box is bad , however all the plugs fire when I test them for spark using the starter. Im next to positive the problem is electrical. Ive tried recreating what happened today and I cant get it to try and fire its just gone back to cranking and cranking.
Im getting very frustrated and today just seemed like the bike teased me to keep me interested.
Any help (again) would be extremely helpfull, sorry about the long post.
Thanks

[Zooks]

Do you have 'good blue spark' or just spark? A weak spark will sometimes not even cause a motor to fire. It can be misleading when you see the plug sparking out of the cylinder but it refuses to do anything when it's in.

[Pacman]

Are you sure the plugs are gapped correctly?

As above, how good does the spark look when the bike is turned over with the plugs out and held against the head?

Are you sure you have the plug wires on the correct plugs?

Do you have at least 12 volts at the coils?

Chris

[Big T]

Pull the plugs out, set them up against the head (or wherever you can ground them)
Turn off the lights, press the starter button

What spark color do you see?

Red is dead
Yellow is fair
Blue is good
Blue/white is just right

Test for 12V at the coils, do the coil relay mod if below 11.5V
Test the coils

Then report back

[Nessism]

...also, remove the drain plugs from the carbs and see if there is gas inside.

[triple6cafe]

Thanks for all the replies. Plugs are gapped according to the clymer, i dont have the book with me (in the shed with the bike) but I think its somewhere in the .70 range. The spark is blue white so thats fine. Gas is in the carbs. The only thing I can figure is that somewhere along the line its got a wire that is either cut, frayed, split whatever. I mean it is a 26 y/o bike with 26 y/o wiring. Is this a possiblity?

[Zooks]

Broken wire might stop it from actually starting but if you have spark and fuel it absolutely should fire.

[Buffalo Bill]

Just a learning experience, don't fold up.

Are you sure you have the plug wires on the correct plugs?

Chris

You didn't say you checked the above.
You just rebuilt the carbs, so you have all idle jet settings at the recommended settings, and using the choke. You may be too rich, and flooding the plugs. Are the plugs flooding up real fast?
Clean the plugs, and try with no choke.
Tip: To save the bike battery, until you get this bike started use jumper cables from a car battery-car engine off.
Don't crank on and on, God will not be impressed. This is about combustion, use reason. It will start right up when you get it right, the way the engineer's designed it to be done.
After you do get it started, the idle mixture will have to be fine tuned, and the carbs synchronized.
Bill
P.S. We don't know what condition this engine is in. Could it be the engine has internal damage, to the valves?

[lucabond]

What voltage do you get at the coils ? Does it have points or electronic ignition? Any chance when you put the tank back on it shorts out the coil
supply line