127.0.0.1 in access log

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!

Re: 127.0.0.1 in access log

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