vacuum leak at airbox drain pre-kat

[GaryS-NJ]

I was on the wiki and saw a write up on vacuum leak sources and it mentioned the airbox drain. I had been chasing down a high 3000 rpm idle on my '95 kat 750 and gave up so I swapped parts into a jarkyard set of carbs and pulling this carb set (high idle is down but #2 not firing...), the airbox drain hose stayed connected to the airbox and I saw how the cap at the end of the hose (which looks removable but isn't) is ripped (looks like chain damage) AND COULD LEAK AIR IN. This would allow air to bypass the air cleaner and make it directly to the carb inlets but is this significant? could it cause a high idle otherwise if not, should it really be sealed??

[skjeflo]

Should be sealed and the cap should be removable. Mine was stuck as all get out when I first got my bike, but it is a drain line for a reason. Stuff needs draining every once in a while!

[KAT TOY]

+1

[GaryS-NJ]

I taped it closed. logical it has a drain for accumulation of oil or gas if you flip carbs upside down.. But my real question was how significant could an air leak be there in terms of my 3000 rpm idle. but like everything else, I noticed it last when I was already committed to swapping carb bodies. I'll pull it all off to check when I get around to finding a good removable cap. I have a parts kat here I can check..

[maniac1886]

I used tape on mine for 4 years and it was fine. I wouldnt suspect that's the culprit for the high idle though. There are orings between the intake boots and head that flatten out and create an air leak also. You may want to check there. Are you familiar with performing vacuum leak tests to isolate the area that's leaking?