Bonneville America Forums Forums Technical Forums General Tech Oil Coming From Airbox Drain Tube

Last week i noticed a significant amount of oil under my '03 America after a 9 mile ride. Figured out it was coming from the airbox drain tube. Figured it was from the oil being overfilled when i bought the bike a year ago or from a tip over from awhile back and that it just took some time to leak out. I popped out the plastic plug and let it drain out. Just went for a ride and noticed more oil. The oil is warm. If i let the bike run the oil drips out faster. Oil level in sight glass looks normal. What could be causing this much oil to make its way to the air box drain tube? Thanks for any insight.

I have the same leak...now. I didn't have it before I changed the oil, but it's there now. I have deduced that it is from the rubber hose that runs from the clutch/transmission area on the left side and runs to the air box and not from the filter area. Why, now after an oil change, has oil decided to migrate up there, I don't know. I applied air to the hose on the transmission end and oil started dripping.

Have you over-filled the oil? Is the bike truly level and not been running for a few minutes when you check the sight glass?

Voltron, since yours started after an oil change I would bet that you overfilled the oil. The oil level should be checked via the sight glass when the bike is NOT on the sidestand. If you filled it whilst on the sidestand and went according to the sightglass, then you definitely overfilled.

If that's not the case, mine ended up being the crankcase breather seal inside the clutch cover.

I don't think I overfilled, but I'll check. I filled and checked the oil while the bike was level.

I don't know whether to celebrate that it was an easy fix or mourn that I was the idiot that overfilled. Either way, time for a beer!
It appears that in the months that I've been riding a motorcycle I have a lot to learn about the machine. I promise I'm not just an idiot with a wrench. I was an auto mechanic for nearly 10 years. Although, the contrary seems to be true in this case.
Thanks for your input.

Glad the fix was straight forward.

Voltron, the oil that has collected in your airbox will continue to seep out for quite a while.
If you pull the top off the air filter and remove the filter itself you can get some rags in there to clean up the oil.

Nah you aint an idiot. People make mistakes, misunderstand instructions, or what have ya. It happens to the best of us.
These bikes are a little bit of a different animal than a car but the principles are the same. Keep on keepin on. Feel free to ask questions there are some sharp guys on here. Glad the fix were easy.

Voltron, what part of the Hoosier state do you hail from? I remember some excellent riding there, particularly in southern Indiana.

Brown County IS a great place to ride. Southern Indiana has beautiful, hilly topography with great twisties.

TonyG,
There are apparently two sections to the internals of the air box because there's no sign of oil in the air filter chamber. There are two identical drain tubes side by side from the bottom of the air box. But you're right, it'll seep oil for a while. People might think it's a Harley if they notice the oil spot first.

Smokey,
I live in the area west of Evansville and east of Illinois. Not bad riding country. Not as nice as Hoosier National Forest which is due east of here. Winding, hilly, wooded area. Very beautiful in fall and spring. I have family that lives near the western border of that area.