Getting fuel in engine oil

[Mooseman]

My new to me and very first brick seems to be getting fuel in the crankcase. There is a valve between the fuel tank and the crankcase. How do you test it? The hose from the valve connects to the front of the crankcase and the other larger hose goes to the rear bottom of the fuel tank. Which in turn connects to a fitting at the top of the tank just behind the filler cap this in turn has a hose to the bottom of the fuel pump filter intake. I take since it's a CA model it must have something to do with smog? Could it be sucking fuel into the crankcase? Instead of fumes? What if I remove the hose from inside the tank so it's not setting in fuel but sucking fumes?
1986 K75C 
Thanks, Mooseman

[billday]

That hose vents vapors from the tank to the crankcase for emissions control. As long as it's connected right, it can't suck gas. A one-way valve keeps crankcase vapors from going back up to the tank. Lots of people plug the nipple on the engine block and let the vent dump out underneath the bike. For a fancier solution search Motobrick for "air collector cup" (I think).

[Mooseman]

Well I think I have the problem solved and am working on getting it corrected. I think I have a leaking fuel injector(s). The problem has gotten better but I believe a through cleaning and testing is required. Problem was the bike sat for 14 years. Everything else is spot on or has been corrected. So the injectors are out and off to the shop tomorrow. Will update when they are returned and installed.
The fuel vapor hose and check valve all appeared OK and in proper working order.  :clap:

[drut]

Well I think I have the problem solved and am working on getting it corrected. I think I have a leaking fuel injector(s). The problem has gotten better but I believe a through cleaning and testing is required. Problem was the bike sat for 14 years. Everything else is spot on or has been corrected. So the injectors are out and off to the shop tomorrow. Will update when they are returned and installed.
The fuel vapor hose and check valve all appeared OK and in proper working order.  :clap:

+

Glad you seem to have found problem:over fuelling would do it.Bonus will be a sweeter running bike.

[TX brick]

BMW put out a letter years ago to plug off the fitting in the crankcase and route the hose to the right footpeg mount. The reason is the possibility of fuel in the oil.

[drut]

BMW put out a letter years ago to plug off the fitting in the crankcase and route the hose to the right footpeg mount. The reason is the possibility of fuel in the oil.

Thanks for that:something Idid not know!

[Mooseman]

Thanks for that info.... sounds like a winner... I can see where that could be a problem when the tank is topped off accelerate engine sucking fumes and gets a big gulp of gas from the breather fitting to the rear of the fuel cap on top of the tank.