Greg Brillus
Hi there, I've seen this on a couple of our section members bikes, including my own Rapide. What i put it down to is, firstly check and see if your tank vent ie: chain oiler pipe has been blanked off. Or on a "C" tank, that the adjusable chain oiler screw inside the mouth of the tank hasn't been screwed right in, blocking the oiler all together. From what i can work out, this set up is fine at around town speeds, but at speeds of 75 to 80 mph and above at a constant you will find that the oil tank is only able to vent through the tiny hole in the cap. When you understand that the return volume of oil and air back to the tank is far greater than the oil being used from the tank, its easy to see how all this extra volume of oil, mist, and air must escape somewhere. I can only conclude that you must either vent the tank via its original chain oiler (breather) pipe, maybe redirected more toward the rear of the machine (away from the tire at least!). Or slightly open up the tiny hole in the cap to say 2mm.Try that... cheers.. Greg.