YZF 750 not firing on No3 cylinder

[Teego]

Won't be valve clearances. If you have a reliable spark at the plug it's a fuel issue.

[Fatdog]

I would agree with Teego, it's a fuel issue.
Could be a faulty float needle valve.
I've had one go before.

[andy88]

A compression test would help... Do one to rule out a a goosed piston...

I've seen holes blown in piston tops..

Have you done a physical check on your headers whilst the bike is running.. Touch them,,, carefully to see if it's hot on no3..

If it is hot, strip your carbs, check and clean everything and reset float heights etc.

Also check your wiring to coils.

[Stig]

Stuck inlet valves on no 3?

[Gord]

I haven't had time to do much with this problem recently, I done a compression test yesterday the results are;

cyl1 dry 120 / wet 235
cyl 2 dry125 / wet 225
cyl3 dry 125 / wet 210
cyl4 dry 130/ wet 210

Cylinder 3 is cool to the touch and the plug is still as new (fitted 4 brand new plugs), so it hasn't ignited any fuel.
I have taken the carbs off and will strip them down and give them a clean next.

[Gord]

I finally got around to checking the carbs today, the needle valve had a bit of muck in it, stopping it from working properly, all sorted now.