LH outboard cylinder cold -- KZ 550A1

Have recently had the engine out of the frame to solve timing chain noise, and was lucky to only have to retro-fit a manual tensioner. The machine is fitted with TK carbs, 115 oversize main jets, open velo-stacks and a 4into1 Kerker. Got it back together and started, and she idles, but the LH outboard cylinder wont fire. There is spark at the plug, and is apparently getting gas (slight leakage from over flow pipe), but stays cold. It worked OK before taking out the engine. Have yet to check compression or valve clearance. Other ideas anyone?

Spray some carb cleaner (or something else that will fire a cylinder) into your velocity stack while running to check for fuel starvation . Also , pilot jets are so small that they clog easily . How long were your carbs unused ?

Do a compression check, that will tell you a lot!! Fuel out of the over flow does not mean it's getting into the engine (float problem?) Is the plug wet? Is the spark a nice bright blue?

Got it lit -- reset float heights, sorted out firing order and replaced HT cables/caps -- it is now positively dangerous to the operator -- thanks for the help!