Bike runs great but backfires had jets done - 2001 Yamaha V Star 1100 Classic

its running lean. Could be a vent problem with the gas tank. try running with the gas lid slightly open.. if this doesn't work increase the jet size in the carbs.

either the idle jet in carb is clogged, and or it is running to lean

Its not common with YZ but is very common with not starting the bike for long time - you need to take out the pilot jet and replace it with new, You could clean them but why bother they about $5 each?
If I were you whilst you have the carbi off I would change all the jets to new ones especially as been sitting for a while (not essential but worth while as off already?)

running only with choke on and backfire are classic symptoms of blocked pilot jet or incorrect size pilot jet so chuck new one in and you should be good to go
The pilot jet is the jet closest to the engine when carbi was installed (it has perforated holes on the side)
good luck regards Jamie

The carbs have to be jetted. If they are the slightest bit out, it will backfire, burn your eyeballs from the fumes and skip and sput like crazy. I found the Dyna-Flow adjustable kits work great, the should have one for your bike, I found one on ebay, because after going to Italy (Ducati) and getting the factory setting jets put back in the bike, it still wouldn't run. I took those carbs off 20 times, the first time took me an hour, I can get them off there now in 10 minuets. Anyway, the adjustable jets work great, it fired right up and ran perfect the first time. Still running great. I am sold. Check them out.

It is in the carbs, A bike will act like that when it needs to be jetted, most jets are not adj, but whoever built the bike, must have messed with the carbs, you can go back to factory settings, which is about 1 1/4 turns out, and try it, you might need to get new jets, you might want to try dyno jet kit, they are adj and work great.. I had to do my bike, the exhaust was burning my eyes, backfired, wouldn't run, factory jets didn't work. But I found a dyno jet kit on ebay, and it works great. But before you take the carbs off, take a piece of heavy paper and cut the air intake in half with the paper to see what it does, then cut by 1/3, then 1/4, just to see if the intake is messing with you. Check it out, hope it helps.

Not sure exactly what the problem is but if I had to take a guess, I'd say that it is running lean and once it's good and hot, it's just a bit too lean to idle correctly.

The bikes come jetted or mapped, depending on whether its a carbed or fuel injected bike, on the lean side to meet EPA emissions standards. The addition of the V & H pipes probably made the situation worse.

If it's a carbed bike, you need to change the low speed jet up one size and add a 0.020" inch thick washer under the needle. Try just changing the jet first.

If it's fuel injected, I don't know because I don't work on the injected model bikes, you'll have to take that to the dealer and see if they can remap the fuel system control for you.

great news you can only win with this. i bet if you pull a spark plug and look at it, it will be white or close to it. if so your motor is lean, it's not get the right amount of gas. when you put pipes on a bike it lets more air flow and you need to jet your carb. you local bike shop can help you get a jet kit and handle the install if needed. when done right you get more performance out of it. while you are look into jets get a high flow air filter or look into a hyper charger they come a jet kit, k&n air filter and the air scoop price isn't bad rsports.com/wps/Honda_OEM/HondaMC.asp?Type=13&A=474&B=25

your idle jet's is blocked

change the jetting...youcan contact FMF for thier setup recommendations for running that pipe with the bike...very common problem and jetting will take care of alot of the issue

yes,

check the jetting on the carbs

there is some great info on highlifter.com/forum along with how to do it good luck!