There are some russian posts that are not converted correctly and that borks the search. I’m slowly crawling through the problems and manually copy the problematic posts from the old forum back over the posts in the new forum.
Sounds like a lot of work. If it is an mysql db behind I think it would be possible
to dump the database into a text file, use iconv to convert it to UTF-8.
and probably some database colums have to be altered as well to UTF-8.
In the meanwhile google can help to workaround (hm, google rules the world):
I’ve already done this and even wrote an extensive script to do this, but even iconv cannot automatically fix posts with e.g. mixed latin1 and utf-8 charactersets. Posts consisted of a mix of charactersets and encodings because the old forum did not support utf-8 properly, the new forum however does.