I put in the 178 shortly after breakin (came in the spare carb parts with the bike). I changed to the next size smaller this past wkend which is a 175, as I new it was still a bit rich, and we went to W. Virginia which has a bit higher elevation than where I ride normally. Bike ran awesome, plus for the first time. it would idle endlessly instead of it dropping to the putt putt boggie idle like it used to after about 15 secs.