Try for example searching 'drive chain'. Are we to believe that there are no posts containing those words?
(And, yes I've read and re-read the tips,
Errrm ... On the Search page, if you click on "Advanced Search Tips" beside "Keyword Search Terms", a small page comes up with three "Tips". The last is, "Use quotes around a phrase to search for a phrase". I just tried "drive chain" (including the quotes) and got the "Your search for '"drive chain"' returned 200 results." message and links to the first 25.
Btw, the top message is yours in this thread ...
When all else fails, RTFM?