Carb 2 Questiom

Hi everyone, just picked up a 1978 kz650 and have a question. On the bottom of carb 2 there are 2 nipples. The one to the right is draining down a hose. The one to the left is open. Should it be capped? I'm a total noob and appreciate any help. I attached a pic showing the bottom of the carb. Thanks.

Howdy. Your motorcycle has VM24 carburetors w accelerator pump. One of the ports is for draining the carburetors & checking the service fuel level & the drain screw should stop the flow when seated. The other port is the overflow in case the fuel level in the #2 carburetor is too high for whatever reason.

The accelerator pump is a mechanical device that adds a squirt of fuel to each carburetor when you twist the throttle, such as during heavy acceleration. It was added to compensate for a lean condition because of EPA regulations. Each carburetor body has a pump nozzle that projects into the carb bore. You can test the pump by supplying fuel to the carbs, then twisting the throttle >> fuel should squirt out of the nozzles & thru the carb bore without hitting the carburetor walls.

ps: in your pic the pump rod is bent.
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Some people eliminate the accelerator pump system and just re-jet a little richer (maybe a needle adjustment?).
You might have to google to get details or maybe someone here will chime in, who has done it.

Thanks a lot guys. I appreciate it.

So i guess putting a cap on the left nipple is a bad idea!

I would connect tubing & route it behind the engine. Also, to identify which one is which, you could open the drain screw to see which port flows fuel >> that one would be for draining the carburetors or doing the service fuel level check. The other one would be the carb overflow which you do not want to plug.

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Thanks! Much appreciated help.