What radio are you using?Something in the area may be on the same frequency as you ?Double sided tape does not reduce vibration.I used a piece of foam to reduce the vibration and used a zip tie to hold the Rx in place.It definitely sounds like a Radio problem.The engine tuning and tuned pipe should have nothing to do with your problems.The only things it could are is to much vibration,radio interference,dead batteries,antenna touching metal,or faulty radio gear.Try changing your crystals to a different channel and change your batteries.