Cylinder temp question

[Jack G]

1975 Honda CB750K, #4 Cylinder about 160 degrees F cooler than other 4.
Compression all about 135 psig, overhauled the carbs fuel in bowl is clear and levels are
#1 & #3 is 45ml (1.5 oz), #2& 4 is 40 ml (1.4 oz)
Used a Fluke non contact thermometer and got the following temperature on fin at 12:00 position above exhaust pipe, outside temperature  was 25 degrees C ( 77 degrees F), bike brought up to temperature and at idle not moving
#1& 2 read 134 degrees C (273 degrees F)
#3 read 132 degrees C (270 degrees F)
#4 read 44 degrees C (111 degrees F)
Checked spark and was strong, has an electronic ignition system
My best guess is the #4 carb slow jet (it did look ok when carbs overhauled)

[Re-run]

Sorry for the late reply.
Your issue would be either spark or fuel. Easy test would be to swap the wires and plugs on 1 & 4. If the problem stays, it is fuel. If it moves, it is something in the wire or plug.

If fuel, then the first stop is the idle jet. You will need to pull it out and clean it.
Also, check the plug insulator. What color is it? you may need to adjust your air screw.