Cough off idle
 

Is everything stock?

Sudden lean conditon. Have you changed the intake manifold seals, carb to manifold seal, new vacuum/fuel lines, and done a carb rebuild? On a 12 year old bike, all those things need to be done. Remove the small metal plug on the bottom of carb so you can access the idle mixture needle when you rebuild carb.

John

stock except exhaust v&h longshots

yes all done plus 190 main jet 45 slow jet. new fuel valve and filter new vacuum line new plugs fresh oil change. does not act up when cold ride it 10 miles runs good ride about 20 acts up

One more question and I won't give you shit about you saying all stock except for the pipes, when you changed the jets, which makes it hard to try to help you without all the information. When you say it runs ok when cold, is that with the enrichner being used a little? It seems to me with limited information that your idle mixture is a little to lean. How many turns out on the mixture screw?

21/2 turns out run choke a few mins turn choke off runs and rides great for about 15 miles no problem when going thru gears or at cruising speed. problem starts when I go to stop starts to idle funny tries to die sometimes throttle to pick back up then first little bit of throttle to take off it coughs thru carb. oh it was doing all this before before changing the jets or doing anything to it. have a map sensor/mass air flow and cps on the way. but I hate to just throw parts at it.

Does this do it all the time or is this just an occassional weird flukey thing?

I have a carbed bike that will pop like that super rarely on cool days when it's about 2/3rds warmed up, just off the enrichener. Once or twice a month in the spring/fall. That's pretty normal.

If you've checked and rechecked for vacuum leaks and can't find any, it's time to revisit the carb.

If it's happening basically all the time, make sure the accelerator pump is working. Especially at 10+ years old these can go bad. That's an easy visual check to see it spraying with the air filter off. If that's good, time to look at jetting.

A 45 pilot is plenty rich for some, but your specific situation may need a bit more, some people run a 46 or 48 pilot. Also, the needle is important- what needle is it? running any shims?

only does it after about 15 miles onlyat idle and coming off idle

If it pops all the time after completely warmed up you have a lean condition caused by typically one of 3 things-

1- Vacuum leak, often at Carb to Intake/Intake to Head seals
2- Accelerator pump failed
3- Lean jetting, mostly on the pilot/idle mixture adjustment.

If this is a condition that has gotten worse/grown over time, it'll either be 1 or 2. If it has always been like this with your set up then it's more likely to be 3.

I agree 100% with John, if you haven't already, do a total clean and reseal of intake/carb track and clean of carb with replacement of accel pump. A lot of people do this but don't realize/forget to do the intake to head seals. Each intake seal is only a couple bucks. All in maybe 30-40 bucks buying parts from the dealer and doing labor yourself. Once you know that stuff is 100 percent good, then you can address jetting if it still acts up. The worst thing you do is chase what you think are jetting issues when in fact you have a leaking intake seal or a bad accelerator pump.