I have a Kerker pipe on this 86 of mine that I tried to remove before I sold the bike the first time & never could get either rear pipe to budge. I sprayed PB Blaster on it every day for a week & nothing. I kept hearing the old mith of mix 50% Transmission Fluid & 50 % Acetone so I fiured what have I got to lose at this point. I mixed some up & sprayed it on the pipes & with an hour one of them came lose one of them is still stuck but hopefully it will come lose. I dont know if I will ever buy any PB Blaster again.