Topic: 1978 CB550 will not start

[Lavis500]

I still think that if the starting fluid isn't lighting, there is a different problem here.  How old are your spark plug caps?  Do you know what their resistance is?  If they are too old, the resistance could be high enough that your spark is arcing from the caps to the head, never reaching the spark plug.  The cap may be far enough from the engine during a simple spark check (removing the spark plug, grounding it and turning over the engine) that it shows a nice fat spark.

Resistance check is too easy.  Pull the cap off the plug, unscrew it from the wire, then run an ohmmeter over it.  Any half decent multimeter will have an ohmmeter.  Here's a great thread on it:  http://forums.sohc4.net/index.php?topic=67096.0

Also, since you said both 1 and 4 were wet with fuel, maybe run a quick continuity test over that coil.  It is just as simple.  Take your multimeter and set it to continuity mode.  You can also just run this test in the resistance setting and watch any changes.  touch one lead to the 1 spark plug wire and touch the other lead to the 4 spark plug wire.  Any change in your readings, or the continuity beep, means that the coil is good.

I don't even have a fraction of the troubleshooting experience that TT does, but I figure even if both of my hunches are wrong, they are very quick, simple checks that don't hurt anything and require minimal effort.  Good luck finding your problem!!

[TwoTired]

A little extra bench work might help out.  Stick the carbs upright in a vise and fill them with gas.  Use the clear tube on the drain and run it up the side of each carb to find the internal fuel level.  This verifies that the float height setting was done correctly.  (This is also where you can do the bench sync (if required).

Also on the bench, operate the choke to observe full and even closure of the plates is possible.

Cheers,

[Oddjob]

I'd also check the O-Rings between the carb manifolds and the cylinder head aren't perished or missing. A large air gap like that would make it extremely difficult to start.
I'd recommend fitting new NGK spark plug caps as well, resistance in caps usually increases with age, having resistor plugs along with resistor caps means little to no spark getting through, even with starter fluid it may not start. If you haven't already fitted the D7EA plugs I'd do that as well, clearly with mention of a choke cable this is a K3 model, as TT has said check the flaps are opening closing as expected whilst the carbs are off.

I do seem to recall the IMS shouldn't be 2 turns out, been a long while since I worked on a K3 and it does have different carbs to the 500 and 550F1 and 2 but I think around 1 and a half turns out from light seated was about right. Main jets should be 90 and slow jet can be either 38 or 42 depending on the market it was intended for. Air jet was either 130 with the 38 or 120 with the 42, slow air jet was 150 on both versions.