[primal]

I just took a peek at the Muffler swap thread in the How To section and saw that you did in fact adjust the carbs by shimming the needle and richening the mixture, i.e. the same goal that rejetting accomplishes, but it just so happened that the required adjustments were able to be made without changing to larger jets. So, I guess we were both right in that you don't necessarily have to rejet, but you do have to richen the mixture to get the bike running well.