#4 cylinder not firing... please help!

[Dexter]

This started happening today. I was stopped in traffic when all of a sudden it shut off. I tried to start back up and it sounded like there was a dead cylinder. I tried for 5 minutes at the side of the road and all of a sudden it started right back up like nothing was wrong. It happened twice more on the way home.

I thought it was ignition related, so when I got it home I pulled the plastic off and checked every wiring connection that had to do with the coils and ignition. Everything looked fine, but I didn't pull the plugs. It seemed to run fine until about 10 minutes ago.

I got it to idle, but it was running funny. I checked the temp at all 4 pipes... #'s 1-3 were in the 400 degree range, #4 was 150 F.

What should I try?

[ctandc]

Plugs

[Dexter]

Could it be something so simple?

[Bright Wire]

Spark plugs are the easiest to check. based on the description. When it did fire up did you get a pop sound like a firecracker? It would be that plug catching finally.

[arsenic]

Spark plugs are the easiest to check. based on the description. When it did fire up did you get a pop sound like a firecracker? It would be that plug catching finally.

Honestly, they ARE about the easiest thing to check.

[KenpachiZaraki]

I think the magnetic flux-inducing capacitor with 220 electro high discharge coils are going bad. but really i think that's the easiest thing to check

[Bright Wire]

Compared to pulling the carbs and cleaning them or digging into the engine I would say that pulling the plugs would be easiest. It doesn't mean they are easy and quick though.

[Dexter]

I'm an idiot for not checking them when I had the tank off.

[arsenic]

yes, yes you are

[WyredHardware]

hahaha

[Kfreak]

Here is a helpful tip: go to the auto store and buy the self adhesive vinyl trim and trim the edge of your tank. I have had my tank off so many times I chipped the crap out of the paint. A full tank is heavy.

[Dexter]

Well I checked the plugs... the ones that were in there were practically brand new and they all looked perfect. I replaced them with properly gapped new plugs from the dealer anyway. I checked and used dielectric grease at all connections at the caps, coils, and even the coil connectors. I started the bike back up and it's still doing the same thing.

It started and ran fine on all 4 cylinders, then after a while it started running like a cylinder was missing. The #1 and #4 cylinders started to go cool while the #2 and #3 were 450 ish. I thought I might have a bad coil but it tested OK as per the shop manual. I put it back together one more time and only the #4 is running cool again.

I don't know if I've ruled out an ignition problem or if this is carburetor related. The problem is intermittent, and I can't run the bike with the tank off.

I don't know what to do next short of towing it to a shop.

[Dexter]

I brought it to the shop.

[elkat]

Should've cleaned your carbs. A sticking float will do the same thing. It'll wash the plug out with gas, and then it won't fire. Happens to me all the time because I still need to clean my tank out.

[Dexter]

Well it turns out it was the coils. They replaced the battery too because it was crap.