Hello I have a standar MC21 . Can you advise me what is a good exhaust for a standar bike ? How much power can it climb? Is a good idea changue only the can ? it improve the bike too ? thank you for you advise and experience with exhaust

Dog Fight brand are very good, so too are Tyga, do a search on here to get some ideas. You will have to make sure that your jetting is correct if you do change the expansion chambers, otherwise you risk damage to the motor!