Recently changed an exhaust system on my 96 R1100RT. Muffler and Cat from a 98. Upon start-up, a horrendous amount of smoke and rough running. Called my dealer (Hermys). Herm suggested that plugs might be the answer. 2 Autolite 3923's and $4.23 Later, the bike started and ran like is was supposed to in the first place. I can't say enough about those super cheap and super efficient plugs!