Rebuild the bottom end, a leak down test can confirm an issue there. Have the bore checked for being true. If your ports are shiny, hogged out, and the cases match, forget it. It would be very expensive to replace, or just live with it. Ignition being off is easy. Or, the way the bike is being used. You have stated some really wild rational to begin with. Running 40:1, you are too lean on oil, and SUPER rich on the gas, it may not last long if properly used. Fix the motor and repack the silencer, mix at 20:1~28:1, JET the bike. A side note: Burn, dip or get a new pipe. All that crud in there is not going to help. Everything I wrote, will and can cause spooge, except the premix ratio. That is cheap insurance, cheap horsepower, and cheap killer throttle response. Properly maintained, spooge does not become an issue. Neglect her in any method, and she will spooge? Vintage Bob