Disconnected hose mystery

[mbelew]

It is wonderful to see such an active forum, for an older bike. So maybe you can help.

My son just bought his first motorcycle, a 2006 Ninja ex250, and we are taking it "apart" to do maintenance. We removed the air box yesterday and sitting disconnected under it was a hose that is about 8 inches long, I guess about 1/4 od. It has a factory plug on one end, and factory spring clip on the other. The strange thing, IMHO, is that it has what appears to be transmission fluid in the hose, pink/red in color; oil like consistentsy. It has been a long time, 20 years, since I have had a motorcycle , but I can not think of any place on the engine that would have this type of hose, with this type of fluid.

Any help you can give would be great.

Thanks Mike.

[Racer x]

Welcome
Can you post up a photo of the hose lying in the spot you found it?

[csmith12]

The drain hose as pictured?

Welcome Mike!

[Kestrel]

OP, that's likely the drain hose for the air box. Ninja 250 utilizes an oil soaked air filter, and the tube catches the run off from that, as well as any oil vapor that may collect in the air box. Red color matches some of the filter oils that are available, and likely explains what you're seeing. Just drain the tube, and carry on as usual.

[mbelew]

Thank for the quick reply.

I looked at the diagrams online, and was able to find it. Sorry for the post before researching more. Can you think of a reason it might have red, transmission like fluid in the tube. I think that is what was throwing me off. The fluid was clean and the tube almost full.

Mike

[mbelew]

Kestrels answer about the oil covered filter makes perfect sense. Thanks for the help.

[csmith12]

It's reddish because of dust, dirt and oil filter oils available on the market AND... isn't this hose normally plugged by the factory?

[Brother Michigan]

I think we should make a sticky for this problem; seems like it pops up every couple of weeks. We could name it "What's this disconnected hose?"

(No disrespect meant toward the OP at all, it legitimately is something that gets asked very often.)

[Motofool]

Originally Posted by csmith12

...... isn't this hose normally plugged by the factory?

Yes, that hose has a removable plug to avoid infiltration of non-filteted air and meant to be removed about each valve adjustment and drain excessive oil.
Oil accumulation may happen because the admission valves tend to spray some oil back onto the filter during compression overlap.

If no oil comes out, it is time to wash and oil the foam filter or to replace it when it develops some gaps.
The hose gets hard with Sun light and becomes easily detached from the air box, even when it has a wire clip at that connection.

Welcome, Mike !!!
It is wounderful that you are helping your son with his machine.

[xorbe]

Red, because someone used red Mystery Oil (a brand name) to soak the filter.

[spooph]

Originally Posted by xorbe

Red, because someone used red Mystery Oil (a brand name) to soak the filter.

Yes, or nearly any other foam air filter oil.

On the new gens they just made it a plug. The Pregens have a longer tube to give more of a buffer, and although it SHOULD be drained every oil change as MotoFool stated, it can go much longer. It's mainly there to catch water condensation which forms on the "dirty" side of the air filter because the oil in the air filter forms a barrier to water. The condensation runs to the bottom of the airbox and is captured in the tube. If there is very little water, it will evaporate in a dry climate since that side of the airbox is open to the atmosphere and all that will be left will be excessive oil from the air filter element.

The important part here is to make sure the tube doesn't get so full that it start to overflow into the airbox.