I had the same problem with a Lear35 downloaded from the internet. The problem was solved when I started landing with less airspeed than I did before.

The RV-4 is a taildragger if I remember correctly. A friend of mine built a radio-controlled model of an RV and we had the same problem of bouncing. I will try to explain this without getting to technical. In the real world of piloting (yes I am a pilot), we have to be careful in taildraggers, they are the world's natural bouncers (well, except a Cub maybe). Make sure when you touch down, do it riiiiight above stall speed (don't use the C-182 points) and do it with up pitch, cut throttle just before landing. Landing flat in a taildragger will always bounce, you....tail goes down cause of inertia, and likewise plane rises again.