TB Parts Big Carb Intake Kit. This kit is to be used with the Stock XR50/CRF50 cylinder head - the porting on the intake matches the stock head. This kit lets you install a big carb onto your Honda XR50/CRF50 - Such as the 20mm AFT Carb and many more 20-24mm carbs. Comes with new gaskets and hardware as shown. The carb side mounting holes are 48mm center to center.