Oil in Air Box

[Mike V]

All,
While in the air box the other day I noticed a pool of oil in the bottom of the box. Just enough to get past the rubber bleed nipple in the back of the air box and a dime sized drop on the ground. The crankcase breather valve is new and the bike runs just fine with no problems at all to my knowledge. I'm still a newby to these air box models and gathering data points as I go. I have all the pulse air valve components removed from the box and only the intake tubes (internally) and crankcase breather "T" installed. My question is; what's a normal amount of oil in the airbox?

[Bob_Roller]

The air that comes out of the crankcase breather has atomized oil in it .

It starts coating the surfaces inside the breather tubing, and eventually, collects in the airbox, or drips out of the carbs, mine usually drips out of the left carb when it does it .

I saw a quick cheap fix in the Airheads monthly magazine Airheads about 15 years ago .

The fix was to cut a piece of a coarse copper pot scrub pad, put it in the top of the breather housing .

Theory behind it, was to give the atomized oil a place to collect on before it got further down the breather tubing .

It seems to work for me .

I have noticed that some oil, breaks down a bit faster than others, when that happens, the lighter parts of the oil rapidly 'condense' in the airbox and drip out of the carbs .

When I first got my bike in 1981, I was using Quaker State oil, it was the worse for this, the motorcycle specific oils don't seem to do this .

[Mike V]

Thanks Bob, it occurred to me oil in the air box to some degree is normal or the rubber bleed nipple wouldn't be there. The fix you mention is interesting and I may considr that - but until then I'll just keep an eye on the accumulation.  I thought about directing tubes connected to the "T" into the intake tubes but will just leave things as it is for now.

Thanks!

[MrRiden]

Another tip that seems to work with the copper scrub collector is to keep the oil level just below the full mark. YMMV.

[Mike V]

I should have mentioned in my original post, I always try to keep the oil level below the full mark as i do in my other bike and am using BMW 10w40 for the 650 break-in only. I will be changing to 20w50 soon and I may have overfilled the oil level (or to the fill line) during the first fill after rebuild.  This could very well be a result of that - good pont MrRiden.