I had recently placed a post asking about petrol dampened air filters and I appreciate the responses, but after some reading, I believe this is due to the phenomenon of exhaust reversion. If I remove my air filters and place my hand behind the carb throat while the motor is running there is a petrol mist that collects on my palm. I am running Mark I cams newly made by Gary Robinson, with exhaust and inlet valve overlap at 4 degrees BTDC, and an Overlander stainless muffler that appears to be spiral baffle pattern construction. My questions are is anyone else experiencing this, how restrictive is the Club's muffler, and could a less restrictive muffler cure this. I've heard of drilling holes in the spiral, using a long drill bit to change the character of the muffler. Seems like a Supertrapp muffler, with its "tunable" disc system might be a way to deal with this....Thanks.