Jake Bach, a Long-EZ builder/flyer reports that for almost a year he had had an unexplained loss of about 100 RPM. He checked everything he could think of - timing, compression, plugs, etc., to no avail. Then he decided to modify his air intake system and when he took the intake hose off (which looked perfect from the outside), to his amazement, it had imploded! All the wire on the inside of the hose had come loose and had balled up in the hose restricting the engine's ability to breathe. A new hose completely cured the problem. This is another good point, one that has been covered in the CP before and, also, one that, in fact, caused an accident in a VariEze some years ago. Part of the problem is in the installation of the hose.
It is critical that the spring wire inside the hose be bent in such a way that it can be securely trapped under the hose clamps at each end. We like to bend the wire 90' so it comes straight out of the end of the hose, then bend it 180' so it comes out of the hose around the edge and back along the outside of the hose. Then the hose is installed over the filter tube or carb intake tube and the hose clamps are slipped on so that the wire and the outside string wrap are held securely in place when the hose clamp is tightened. This should eliminate any chance of the wire "spring" coming loose from inside the hose, however at least an annual inspection of the outside, as well as the inside, of this hose should be conducted.