I recently installed apache 2.2.6, with ssl on Solaris 9. It's a
pretty standard install.
In my access log, I see entries like this every couple minutes:

127.0.0.1 - - [03/Nov/2007:15:46:41 +0000] "GET /" 400 480
127.0.0.1 - - [03/Nov/2007:15:46:42 +0000] "GET /" 400 480
127.0.0.1 - - [03/Nov/2007:15:46:52 +0000] "GET /" 400 480
127.0.0.1 - - [03/Nov/2007:15:46:53 +0000] "GET /" 400 480
127.0.0.1 - - [03/Nov/2007:15:46:54 +0000] "GET /" 400 480

I didn't start seeing this until I modified my http.conf from
CustomLog logs/access_log common
to
CustomLog logs/access_log combined
(I wanted more information in logs for webalizer to have good
reports)

What would cause these log entries?

Thanks!

usually your server shouldn't knock at it's own door.
is there a script running that opens document root?