Re building them is covered here:
http://www.hondatwins.net/forums/63-fuel-supply-carburation/24191-rebuilding-vbulletin-carbs.html
There really isn't much "tuning" to these carbs. Mixture issues are corrected by changing jets, generally the primary main jet. There is a fix for issues pertaining to your specific bike:
http://www.hondatwins.net/forums/63...2-honda-service-bulletin-450-drivability.html
http://www.hondatwins.net/forums/63-fuel-supply-carburation/24191-rebuilding-vbulletin-carbs.html
There really isn't much "tuning" to these carbs. Mixture issues are corrected by changing jets, generally the primary main jet. There is a fix for issues pertaining to your specific bike:
http://www.hondatwins.net/forums/63...2-honda-service-bulletin-450-drivability.html