What are the plastic tubes for inside my airbox that go to the mouths of the carbs?

[JeremyL]

I had my air box out and was checking it out while I had my carbs off (again). I noticed these plastic tubes that went to the inlet to each carb, except ONE was missing... I think it was the one that went to the PCV/oil vent/whatever hose. Instead of it going to the carb boot the plastic u-shape piece was missing and it was just venting inside the air box wall. Is this a big deal?

I tried searching for 15 minutes but couldn't find much about them because I don't know what they're called.

[crazy steve]

Those tubes are for venting the crankcase, and I assume Yamaha designed them for a bit of positive crankcase ventilation. Having one missing shouldn't make any difference...

[skids]

I took them out of the airboxes. Who wants oil droplets and gunk to be vented directly to the small orifaces at the carb inlets??? I know the fumes go there anyway, but I removed the damn things as they were pretty cruddy.

[BA80]

I took them out of the airboxes. Who wants oil droplets and gunk to be vented directly to the small orifaces at the carb inlets??? I know the fumes go there anyway, but I removed the damn things as they were pretty cruddy.

A little top end oiling won't hurt a thing, In fact it's a good thing.

There is no other way for the top rings to get any kind of lubrication unless there is a lot getting past the other rings, or your valve seals are leaking, and that there ain't a good thing.

As little as get's in there it will actually help lube the slides and the top rings. FWIW

[JeremyL]

Thanks guys, that makes me feel better. I was sure that it was a cause of my bike running rough. I ordered a new air filter because mine (an original style) has a nickel sized chunk of the yellow foam stuff tore out. I dunno if it's enough to cause it to run loan but dust could easily get through. When I saw the missing hose in the air box I thought with my luck it'd be something major that needed to be replaced.