I have a 2000 Yamaha 650 Vstar with 3300 miles on it, we put new Vance&Hine pipes on it an had it rejetted, last year we didnt ride it very much, mostly sat in the garage, wnet to put it away an it started acting up like it needed new plugs, so i installed them, an wnet to get it going this spring an it takes forever to get it started, an when i do get it running i have to have the choke on all the way, if i shut off the choke it stops running, it also is back firing,i put a new gas filter on it an it still not i put some fresh gas an some carb cleaner in the tank, its probably something im over looking, Thanks Tom

My experience shows about an average of 40mpg. Road, wind, temp conditions, carrying a passenger,. can vary that by 5mpg either way.
If you own the bike you're speaking about, fill it up reset the odometer, put 100-150 miles on it, fill it up again and do the math.
The vstar was an excellent fuel miser, if you plan on doing a lot of your own work, buying a service manual from somewhere like amazon.com for $20-30 bucks, you'll have a sweet dependable ride.

believe carb adjustment bad & carb needs to be rejetted to exhaust, believe you need to add a higher flow gas valve & possibly new plugs & wires

If you rejet, you need to do BOTH carbs.

Use a DYNAJET kit & go with the directions. Or check with the Hypercharger manufacture for correct jetting. But you will still need different needles & main jets for those pipes.

popping on decel is from a lean condition. More likely from a lean, or too small pilot jet.

If the mechanic did not replace the exhaust pipe gaskets in the head or on any connections between the head pipes and the mufflers , the air leaks could be igniting unburned fuel in the exhaust , causing the popping and back firing. Try replacing any gaskets in the exhaust system.
If you have a flat spot or hesitation when accelerating than you probably also need to rejet the carburetors. Bigger main jets should fix that condition. A jet kit may also contain differently tapered needles for the slides to help compensate for the change in the acceleration curve.

All the symptoms you describe point to a carburetor overhaul and float valve replacement.

Previous owner probably had the bike rejetted for the pipes and is over rich. Is your friend's bike stock?

First off did you buy it new? Second has it gone through its break in tune up yet?Did you do the re jeting? My guess is it was re jeted wrong & neeeds to be re jeted again or could also need more air(upgraded air kit) or a tfi or power comand fuel mod.My bike also poped untill I did the air & fuel upgrades & them upgrades will also give you a much needed house power needed for this rig.


Bring it to a shop & have it looked at.......


Good luck

No it will not. You probably don't NEED to rejet at all. If the manufacturer suggests it for your bike and pipe combination I would follow their advice. If they do not suggest it I would use a dyno to get the best performance from your new setup. Keep in mine your new exhaust only lowers the back pressure. You haven't changed the intake parameters at all as far as airflow. So any additional air going into the cylinders due to your new exhaust will only be because of the reduced volume in the cylinder while the intake valve is open. This is a rather small amount, so don't get all crazy and jump several jet sizes at once.