I got the newly carbed + fully air boxed/snuffed bike out today. She was breaking up at higher RPMs. Where it would easily hit 100KPH it now struggled to do 85. Jetting.... OK, we are rich up top. Running it without the filter and box cover its ripping. So in we go. Hit the Joanne Fabric shop for open cell 1/2" foam. Made a nice old school Husky 570/610 style air filter + box cover mod. Bit of light oil on the foam... Back in business. Good midrange, (OK, good for a 75cc), plus it revs out clean.