You shouldent' have any problem with cooling on the RZ, I think most of the guy's would agree that the water jackets may be even bigger than the COOL HEAD.If your head has been shaved and you havent' been ported & polished you really should be running a good race gas(110).The bigger your port & polish the less octane required. Sounds strange buy it's true had it happen to me . Please just buy a set of stock banshee 26mm carbs on Ebay. Run them fat like 34-- 300. Then you can eliminate any questions on carbs, i've heard more guys have problems trying to just get the rd/rz carbs to work right , save yourself headaches and time go with somthing that is easy to figure out.