It's a bit hard to know why without seeing the old and new tours.. how many pages the old tour was, what was being offered, what type of gay site etc.
Changing tours is a stressful time -
www.sexgaymes.com just changed it's tour from an older kinda weird style but not the 800x600 old style you're talking about to a newer dynamic tour. For 6 hours i think we didn't get a single sale and i nearly choked, then they started coming in like an avalanche.. We're converting better than ever before - surprisingly better actually - i'd suggest adding some video type animation and rotating some models on the front so every time a surfer visits they see something different. Also make sure that the content is being updated regularly and that surfers can see this in the release dates, if it means supplementing your unique content with purchased vids then so be it.