Originally Posted by dave green
fitting a sump would not cause this , if it was not fitted corectly it would leak oil nothing more.
Sorry Dave, but thats not quite right...
Bosch KE utilises a closed loop crankcase vent system and constantly draws air from within the crankcase / breathers. Think what happens if you remove the filler cap...
Maybe you had a leak before and now youve fixed it the engine is running excessively rich... get her to a pro for checking over is best advice i can give if shes deffo airtight now.