It worked for me . I have 6 other friends with various bikes that have tried it and it has helped all to some degree.if nothing else it far easier to tune than jet,needle,mixture or float level changes. it really helped smooth out transition zones. no peak HP gain but it is worth the money.i used to make jetting changes several times a year to compensate for weather conditions. now it is much easier.As for the guy on sportbikes.net that said that it can't work, he is wrong. the main air bleed can have a tremendous effect on fuel flow through the main jet.he should realize that there may be individuals on these message boards that are far more knowledgable about caurberation than himself.you can't say it doesn't work if you haven't tried it.