Suggestions on where this leak is coming from

[marcmiller001]

I have noticed some smoking on the same spot of my exhaust in my last 2 excursions. I took some time and located where it is landing and assumed the culprit was the oil switch...which i have a replacement for and new crush washer... but I also noticed oil dropping off the throttle linkage bracket and not sure why. Any suggestions...

Also... any other suggestions on small items to replace to prevent links before winterizing?

[Bob_Roller]

The crankcase breather vents into the rubber ' horns ' in the airbox, oil collects there and seeps out from the carbs .

I usually only see this after a long high speed ride on rural interstate highways, 75 mph, 125 kph speed limit  .

Some owners state that keeping the oil level down to about midway between full and add, will reduce oil consumption .

[Barry]

If you remove the elbow that connects the air filter housing with the carb you may see the inside is wet with oil. While the elbow is off look up into the air filter housing and you should see the rubber horns that Bob referred to. They should hanging in space rather than touching the sides, the idea being the oil vapour is carried by the air stream into the carbs rather than dripping down into the elbow.

The pic is an early round filter housing so yours may look a little different.

[marcmiller001]

Thank you BOTH for the info. I had planned on replacing all the rubber grommets from the cylinder to the airbox this weekend - I might dig in to the airbox too (have a new air filter for it too) and look for any issues.

Anything else I should look for while in there?

[marcmax]

I can't remember where I read about it but I stuffed a small piece of a copper mesh pot scrubber inside the end of the rubber hose connected to the crankcase breather. The theory was that the oil mist would collect on the copper mesh and drip back into the breather. No ill effects on running and I haven't had any stray oil leaks from that area and I did this mod 6-7 years ago.

[BPT]

Maybe from someone thinking like a distiller?    

[mrclubike]

Looks to me like you may have a leaky oil pressure sender and the oil is following the wire down to the  frame

[georgesgiralt]

You may also have a failing lip seal at the gearbox shift lever.
Both are easy to change. For the gearbox, lay the bike on it's right cylinder jug to contain the gearbox oil in during operation... 5 minute job.

[Barry]

Maybe from someone thinking like a distiller?Wink

Pretty sure that was Bob Roller !

[Justin B.]

Two very common, and inevitable, leak points on a Boxer drivetrain are the engine oil pressure switch and the gearbox neutral indicator switch.  Also,IIRC, there is a little rubber valve thingy in the lower rear of the airbox which will allow any pooled oil to dribble out.