Are the plugs Iridium? If they're the copper kind, replace them asap.
How is your battery? With older plugs, and a charge of under 12.3v (bike off) you'll have a hard time starting it (will dip under 12v when bike turns on).
Edit: Also thinking stuff could have loosened up in the tank, and got stuck in the carb jets. I'd check your power situation first, and then look into some seafoam directly in the carbs.
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
Last edited by thtanner; 05-19-2012 at 12:36 PM.