How to test coils

[Tsuka]

Hello everyone,

I'm trying to trouble shoot something on my 03 Katana 600. The bike is currently running on 3 cylinders. I tested using a temp gauge on the pipes and cylinder 1-3 get to roughly 750 degree, with cylinder 1 lagging slightly (at 690-700 degrees) but cylinder 4 was at <200 ish and steadily drops. I pulled the plug from cylinder 4 and checked the spark and didn't see it spark so I swapped cylinder 1 and 4s plugs and got the same condition (cylinder 4 still not firing).

I used a multimeter I had lying around but it only beeps for continuity, it doesn't read ohms/apms/etc. I tested the plug and it beeped and I pulled the coil for cylinders 1 and 4. It beeped when I touched both wire connections and when I put the prongs into each spark plug boot.... but not the boot to the wire connection.... Is that normal? Is there a way I can test the coils to see if they are bad?

A couple side notes... during my testing cylinder 1 hyrdolocked so I removed the plug and blew out the gas and it started back up (albeit the same condition of not firing on cylinder 4) AND I also tested by spraying starting fluid into cylinder 4's carb hole and the temp on the exhaust pipe raised roughly 20 degrees and dropped. Is that more of a fuel issue then?

Don't know if it's fuel or spark related... or a little of both but any insight would be much appreciated.

Thanks!

Tsuka

[Kreylyn]

Coils are a wasted spark design. If one plug is firing, it's working.

if your finding no spark on one wire only, it's the wire, boot, or plug. A common issue is the connection of boot to wire. Remove the boot, clip the wire back to flexible wire, screw the boot back on.

if your problem is same location when swapping coils or wires, its not an electrical issue most times.

the pickup trigger going bad is supper rare.

[Tsuka]

Thanks for the reply Kreylyn!

So can I switch the two coil packs (1/4 and 2/3) to test the wire or would that mess up the firing order for the cylinders? If cylinder 4 still wouldn't fire then it would most likely be a fuel issue?

Another side note I've cleaned the carbs like... 3 times... but I'm a novice so that doesn't mean much lol. I did remove the brass stoppers to set the A/F screws and one thing I noticed is that they were all different. From cylinder 1 to 4 it went 1.5 turns, 1.75 turns, 3 turns and 4 turns. I reset them all to 2.5 turns out but I'm not sure if I was supposed to put them back the way I found them.

I will check out the boot/wire connection tonight and let you know what I find.

Thanks again for your help!

Tsuka

[Kreylyn]

Coils can be swapped... so you can move the wires from the coil on the right, to the one on the left... and then swap the leads from 1/4 or 2/3 configuration, to the new setup... and test if the problem moves. If it doesn't move, it's definitely not a spark issue. If it does move, and follows the plug wire specifically... then it's a wire/plug cap issue.

Krey

[Snakers]

On the side of the #4 carb, there is a vaccuum hose connection that connects to the petcock. If this is not connected, or if the hose is damaged, #4 cylinder won't fire. Also, the float in the carb is not shutting off all the way. Since you just cleaned them, you might be able to flush out the debris by draining the float bowls several times using the screw on side of the bowls. Also also, the petcock should be in the on position, not pri. In pri, if a float sticks, your engine will fill with fuel causing hydrolock.

I'm operating on the assumption you're sparking fine, just not getting a good ground on the plug or not seeing it...

[Tsuka]

Okay so I finally got a small bit of free time to check.

Snakers - I don’t have the tank on, I’m using an spare fuel cell at the moment but I did have that vacuum line plugged.

I took the carbs out and adjusted the mixture screw on 1 and 4 to 2 3/4 out from 2.5 turns. I got the 4th cylinder to fire, (so it’s not a coil issue) but now it can’t run unless it’s on choke.

guess I’ll have to go through the carbs again... maybe the 4th time will be the charm.

thanks for the help guys!

Tsuka