Slight popping in exhaust?

[No1uno]

The bike runs fine, but when sitting getting warmed up, the exhaust has this slight sound of soft popping sounds, like the bike is missing every once in a while?
Not sure if it is a vacuum line, or plugs or whatever.... I have put seafoam in the tank and been running it for 2 tanks. The RPM's seem solid but when I try to hold the throttle at lets say 2500 RPMS it will drop a bit and then go back up? Seems to lag a little on take off... could use some help, the manual sends me off in many directions.

I have had the following done
Carbs cleaned
New air cleaner
New filters on the cruise
New timing belt
Need to do the vac lines next

I have started at the front of the bike and working my way back, I took off the front wheel, buffed it to a nice shine, had new bearings put in, rebuild both calipers, new rotors, rebuilt the front brake master cylinder and put in new brake fluid, now on to the Clutch master cylinder rebuild and Clutch slave.

Also just did the alternator and rubber bushings, new battery etc...

But with all that I am doing, that idle, stumble and gentle popping sound in the exhaust is bothering me to no end.

HELP

Robert

[FM-USA]

I had an issue very much like yours.
Disassemble the petcock, you might find a pinhole at the bottom of the diaphragm.
Use a flashlight behind it, when they're new holes they are really small.
IF it is a hole replace it, ebay kit's are reasonably cheap.
Or sparingly use 'RTV Black' (overnight cure) that little hole only on fuel tank side. Don't want it in your carbs.

VAC LINE 1.) Follow the petcock vac line down to the left side intake you might find another pin hole at the elbow.
'RTV Black' works or there's JUST enough slack to cut & stick back on.
VAC LINE 2.) Below the heat-sheet left carb near the intake is a 1/4" vac line. The elbow (more than likely) has a pin hole or looks cracked.
'RTV Black' it or best to replace it since it's a difficult area. IF you're there, look at the larger VAC LINE opposite the hose (front of carb) for the same issue. IF that tube is open, post back, I have a near $0 fix.
HOPE THIS HELPS

.

[No1uno]

I will dive into that next, ordering parts now... thank you

[MaineStreet]

I'm not saying it's right, but when warming up (i.e., with the choke on and rpms up), my exhaust pops a bit too. Not so when warm and no choke.