Had carbs rebuilt and suppose synced but bike starts hard and when running backfires whin you let off the throttle
1. choke circuits still plugged up or carbs not cleaned correctly; most people that attempt to clean their own carbs do not have the proper equipment to do it with. Most carbs have really small orifice(jets) and require really small jet drills/orifice cleaners to clear them out. Cleaning them in a caustic soak tank will clean them out but the carbs must be taken completely apart or it will damage any gaskets or rubbers parts left in it. Carb cleaning should be left to professionals unless one has experience doing it.
2. Open/broken vacuum lines can make it hard to start and backfire when letting off the throttle; jets that are not cleaned out correctly can also make it backfire.
3. If the backside of the inlet grommets are not sealed at the flange and have a vacuum leak, that will cause hard starting and backfire also; this applies to carbs with a flange style grommet. If the intake grommets are cracked or leaking it too will cause hard starting and backfire. Remove the carbs, wipe the head and mating flange surfaces with laquer thinner, let it dry and then reseal the grommets back to the head with rtv silicone rubber. Make sure to wipe any excess rtv(before it drys) from down inside the port before putting the carbs back on.
Feb 20, 2013 |
Honda F6 C Valkyrie Motorcycles