The carb vent hose is an air vent for the carbs. You want it connected to the right ear, Cut the end at a 45 degree angle to ensure it doesn't bottom out. This may be your problem if wind is going into the tube. It can cause bogging at higher speeds.
The pickup coil gap mod helps with a few things, including hot starting.
1986 Kawasaki Vulcan 750
NGK Iridium Plugs #7803/DPR7EIX-9
Duralast Gold ETX15 AGM Battery
Coastered & Shaved
Metzeler ME880 [110/90-19, 170/80-15]
Balance Dampers Replaced
Rebuilt Forks w/ Progressive Springs
VN750.com Grill Cover
Emgo 23-92411 Handlebars
MOSFET FH012AA R/R
1990 Kawasaki Vulcan 750
1998 Honda VFR800 FI
2014 Honda VFR800F
1989 Pontiac Firebird Formula 350