Buy Yamaha XV535 XV 535 Virago 6 Sigma Custom Carburetor Carb Stage 1-7 Jet Kit: ... Needle Adjusters, Nylon Spacers, Drill Bits, Slide Hole mod (with CV carb), Idle Mixture mod, Slide Spring Mod (with CV carb), Carb Schematic, Specifications, Carb Sync Tool build, Carb Cleaning Procedure, Proper Tuning Techniques, and step by step instructions. PaulSwany wrote (): › If you have some popping at idle, I'd check for vacuum leaks. Check the carb holders and vacuum lines. Check the carb holders and vacuum lines. The way I do it is to spray a little ether or WD40 around the boots while it's idling and see if the rpm's change.