why seal the airbox if there is a drain hose?

[Andrew Vanis]

why seal the airbox if there is a drain hose?

unless my oem drain hose is missing a check valve or something (doesn't seem to be per fiche) it looks like the drain hose cancels any sealing that the airbox may get.

[Big T]

Seems logical, but then. many people have sealed the airbox with excellent results

So sealing does work

[koolaid_kid]

A proper drain hose is somewhat of a one way valve, letting things out but not in.

[BassCliff]

Hi,

The inlets of the airbox, snorkel, small holes on the bottom, etc, are engineered to let in a measured amount of air. That's why any air leaks, which let in more air than designed for, cause the engine to run lean. That is also why when you replace the airbox with pod filters you must enlarge the jets to compensate for all the extra air and maintain the proper air/fuel ratio.


Thank you for your indulgence,

BassCliff

[sedelen]

You know I've often wondered about this.
My '79 GS1000 doesn't have a plug on the end of the hose, I wondered if it was a special hose with some kind of check valve in it. There isn't, just an open hose.
However, my '82 GS1100E didn't have a hose, so I ordered one, and there on the end was a plug with a clip to hold it in place. This is the "revised" part number one, so I don't know what the original had.
So, I ride the 1000 with the hose on the end open, I had it plugged once with a bolt, but it didn't seem to make any difference. And I ride my 1100 with the plugged hose. It doesn't seem to mind at all.

[rapidray]

Ok everyone, I will explain this. Anything that is AFTER the air filter doesn't really affect the engine. The carb boots to the head & the airbox boots to the carbs need to be sealed to prevent air leaks into the intake system. The airbox will affect jetting if it is altered by cutting holes in it or something of that nature, but the bike was DESIGNED to operate with the drain hole. Even if the hose is removed the engine is still within safe parameters for the jetting they come with. Is this stated in a way that is understandable? Ray.

[sedelen]

I know this "aftermarket" air cleaner cover which was on my '82 GS1100E when I got it and thought was stock made a big difference on my bike.
It ran hot and lean and I was thinking it was the carbs. What a difference it made when I put a solid top stock one on it with weather stripping.

[mrbill5491]

why seal the airbox if there is a drain hose?

unless my oem drain hose is missing a check valve or something (doesn't seem to be per fiche) it looks like the drain hose cancels any sealing that the airbox may get.

The new drain hose I ordered for my bike is sealed with a removable plug. So I figure they know something now that they didn't back then. My old drain hose just had a foam mesh in it, no one way valve of any kind, so it probably sucked up some extra air.

[850 Combat]

When I sealed up the rubber snorkel on the airbox, it didn't help that much.

[JEEPRUSTY]

My tube has a check valve of sorts.

[gearheadE30]

Apparently they aren't all like this, but mine is only sealed after the filter. Anything before the filter, except of course for intake restriction, doesn't matter as much because it all has to go through the filter and will be filtered anyway. An unsealed 'box would make it run slightly leaner though.

[bwringer]

Crikey...

"Sealing the airbox" doesn't mean making it airtight.

It simply means making sure that air can only flow into the airbox where and how it's designed to flow. Extra air makes your bike run lean and wonky.

On shafties, the snorkel on the back of the airbox is also a vital part of the equation.

[koolaid_kid]

Crikey...

"Sealing the airbox" doesn't mean making it airtight.

It simply means making sure that air can only flow into the airbox where and how it's designed to flow. Extra air makes your bike run lean and wonky.

On shafties, the snorkel on the back of the airbox is also a vital part of the equation.

I seem to recall where removing a restriction in the drain hose solved an issue on a non-GS bike.

[bwringer]

I seem to recall where removing a restriction in the drain hose solved an issue on a non-GS bike.

Yeah, if your bike ends up underwater, make sure you pull the hose off to completely drain the airbox and check for trout...

[koolaid_kid]