FZ1 Header temperatures.

[Kellyye]

Hoping to get some wisdom...

Long story short bike started misfiring 2 years ago (cylinder #1 header was cold compared to 2, 3, and 4 Left to right) bike also sounded like it was running on 2-3 cylinders. Prior to that the bike was sitting for at least 6 months without being started. Finally got around to looking at it this week. 1. Replaced gas, 2. Replaced battery, 3. Replaced all four coils + new spark plugs...still miss firing.. Finally replaced fuel one more time and bang header from cylinder #1 is getting hot again...compared to before anyway.

I went out and bought an infrared temperature gun just to be sure and measured the following temps after letting the bike idle for 1-2 minutes (250f,585f,350f,340f Headers 1,2,3,4) Header #1 still seems to running cooler than the rest and header #2 is a clear outlier compared to #3-4. Overall the bike at least sounds like its running on all 4 cylinders..

Should I be concerned?

18,000 miles.

 

[Blue Flash]

Wisdom... well... I'm one of the older guys... I don't know if that means "wise", but I'll take a shot at it.
It's either spark or fueling. (duh). You've replaced the battery, plugs, coils.

Here's my "brainstorming" session... things that come to mind for me.

I'm not the expert on what header temps should be, but it looks like maybe 340-350 may be "normal", and you have a high and a low. I think that would rule out anything that would service all cylinders, like the thermowax, fuel pump, etc.

For the low temperature,
Just to be sure it's not a spark issue, have you tried swapping the coils and plugs between cylinders 1 and 2? if the issue changes position, that might narrow down the search. I wouldn't expect it, but it would be one easy check. Can you get a visual of the spark you're getting on cylinder 1, and is it a nice strong blue spark? It should look strong and like the others. A weak spark could be the issue. I've seen where people have cut a small length off of the coil wire to get a better connection. That might be the culprit.

Have the throttle bodies been worked on at all? Are they synchronized? Likely not the problem, but maybe an adjustment that isn't a bad idea anyway.

For the high temperature, it sounds like you are getting good spark, but running lean. Perhaps an air leak in the throttle body boots (cracks or not well seated) OR, maybe have some crud in the injector that is messing up the flow.