Yamaha v star back fire.?(650 class)?

Question

I have a 03 vstar about 9000miles,first bike.I live in high altitude(6500ft) and I get alot of back fire,anything I can do to stop this??

Answer 1

Probably need to take it to your dealer and have them re-jet the carbs and synchronize them.....that high of an altitude would probably change the air/fuel mixture......If the front header pipes are turning gold it is too lean and if they are becoming blue it is too rich....Good Luck

Answer 2

Is it a backfire on decelleration or under a constant throttle opening or accelleration? If on decelleration, richening the idle mixture will certainly help (I assume your bike has a carb). You should be able to access the idle mixture screw although it may be under a cap or plug, so ask your local mechanic. Also find out it it controls air or fuel, even carbs by the same manufacturer can differ.

Either way, turn the screw in until it seats lightly and count how many revolutions it turned. For example, say it screwed in 1 1/8 turns, it controls fuel, so then back it out 1 1/2 or 1 3/4 turns. If it controls air, screw it in. For either type, try a half turn and then ride the bike. The idle screw will affect the mixture up to around 1/4th throttle opening.

If it backfires under constant throttle at road speed, then shimming the jet needle will enrich it. You can make a shim out of a soda pop can or milk jug but you better have good eyes and a steady hand.

If it backfires under accelleration, especially full throttle, then you need a bigger main jet.

If you've changed the pipes or installed a more freely flowing air filter, you may have to tinker with all three. Oh, dirty or worn out plugs will miss on accelleration, the more throttle the more missing but normally don't miss on decelleration.

Answer 3

Plugs are fowled , if you have aftermarket pipes and or a hyper charger , when you warm up the bike do not use the choke at all , warm it up slowly , change the plugs maybe a cooler plug , i had that same problem with my v star 1100 , coolest web site for your bike www.650ccnd,com