kz650 drain plugs

I've noticed that under the carbs there's drain plugs but there's a tube connected to the bottom also so when I unscrew the plug, isn't fuel supposed to come out of the tube? It doesn't. I unscrewed it and the fuel wanted to come out of the screw hole. I'm wondering what that drain tube is for.

Those tubes are overflow tubes.

If the float gets stuck, or the float needle valve won't close, or you forget to install a float or float needle then the float bowl will overfill with fuel. Without the overflow tube, the gas would pour into the cylinders, and into the engine oil.

The drain plug is just that. Unscrew it and you empty that float bowl from the hole you just opened.
It's a messy process, but this is where you attach a tube for the clear tube test, which tells you where your fuel service level is set, and indirectly your float heights.

Your float drains are blocked, if you loosen that drain plug with the fuel on 'prime' it should come out of the drain tube. This is how you set the fuel levels with a clear pipe.

When you take the float bowls off you will notice a load of sediment collected at the bottom. Carb 1 (front left) gets it worst if the bike is stored on it's side stand.

Tyrell Corp wrote: Your float drains are blocked, if you loosen that drain plug with the fuel on 'prime' it should come out of the drain tube. This is how you set the fuel levels with a clear pipe. .....

That's how the later carbs are, but he has an earlier model (1978). On the early VM24SS carbs the fuel drains out around the brass drain plugs when they are loosened; they even have a tiny hole in the threaded portion for that purpose, and the hoses on the bottom of the bowls are strictly for overflow. It's a bit sloppier than the later models. :laugh: Ed