I ran a degree key for 2 years with no problems,the key to it is making sure it is installed right.As for dealers F*CK THEM,I once had a dealer tell me I was buying jets that were "way to large for your machaine".I told the guy that the carbs are not stock,and told him of the work done to my motor and this is what he told me "it dosen't matter what work you have done to your motor,if you need 290 mains Yamaha would of put them in when they made it".