interesting hole. . .
Nah, it's the clutch cover and can be replaced with a new one from Ron Ayres for $150, and a lot cheaper if you can find a used one on ebay.
http://cgi.ebay.com/ebaymotors/HONDA...Q5fAccessories
http://cgi.ebay.com/ebaymotors/90-91...Q5fAccessories
http://cgi.ebay.com/ebaymotors/HONDA...Q5fAccessories
http://cgi.ebay.com/ebaymotors/CBR10...Q5fAccessories
http://cgi.ebay.com/ebaymotors/90-cb...Q5fAccessories
http://cgi.ebay.com/ebaymotors/88-CB...Q5fAccessories
http://cgi.ebay.com/ebaymotors/90-91...Q5fAccessories
http://cgi.ebay.com/ebaymotors/HONDA...Q5fAccessories
http://cgi.ebay.com/ebaymotors/CBR10...Q5fAccessories
http://cgi.ebay.com/ebaymotors/90-cb...Q5fAccessories
http://cgi.ebay.com/ebaymotors/88-CB...Q5fAccessories


