M, No...the TK carbs on your' friends' Virago had "issues", Gas in the oil (crank case & exhaust) is usually due to a float valve problem. (in order of occurance) 1 stuck/sticking float valve (at needle)2.leaking o ring at float valve seat. 3. sticking float (at pin.) Typical failure is a float valve /s fail to seal, & fuel pump overpowers float valve/s & pumps raw gas thru carb & into head. Thus gas in crankcase &/or exhaust..... High mileage viragos of this vintage would also wear out the throats of their emulsion tubes & needles causing them to run "rich" at normal throttle settings.( to the point they were un-availible for years) Your' fuel screw settings are probly screwy due to PO's attempt to correct for dirty pilots. On these bikes it's important to note that jetting was "staggered", double check diaphrams for leaks, & that on re-install carbs are "seated".fuel screws are often "finiky" w/ the "sweet spot" being within a 16" of a turn. luck G
