Deacceleration popping

Heys guys I'm new here and this site has been great in bringing my 1980 Kz 1000 LTD back to life.Only 1 problem exhaust popping on decel.I checked everything from valves clearances to timing, vacumm leaks, fuel levels set to 4mm,the Vm28's seem to be dial in with 17.5 pilots and 122.5 mains,I'm running pods and a Russ Collins 4 into 1. I got this bike about a year ago and rode it while bringing her back to life.I've taken exhaust temps and #3 seems to be cooler but all plugs are the same color any thoughts.

"exhaust popping on decel."...

If all other variables good to spec (manifold no leaks, no holes in exhaust/couplings, jets good, carbs sync'd etc...) >>> Running a tad lean... Change needle clip position for richer ops...

NOTE: May also be due to colder climate temps/higher elevations... Was this occurring in the summer temps as well....

Either way, 1 clip change richer, and go for a ride....
Hold at 65mph and let go of the throttle so she snaps back... Still back fire... Yes/No...

Same test, hold steady at 65mph ~ 4500-5000rpm.. She stumble, surge a tad as she would be needing gas....

If no to either above then good to go....

I'll try the next day it gets above 40 degrees, Thanks

Could first try slightly enrichening the pilot circuits, say 1/4 turn of the adjuster screws.

For side-located air screw, turn clockwise 1/4 turn (reduces air).

For bottom-located mixture screw, turn counter-clockwise 1/4 turn (increases mixture).

Good Fortune!

Although im not sure this bike has the Air Circulation ports on top of the valve cover that run back to the airbox via hoses, for emissions, I know that can cause some popping on decel problems if not working correctly.

You can remove the whole system, plug the ports on valve cover, as well as the hole in airbox.

Just a thought.

Mine was popping quite a bit until I sealed my intakes.

To verify it was indeed an intake problem, I squirted a little bit of gas on the rubber intake boots (between the carbs and the head) while the engine was idling. When I'd squirt the gas, the engine speed would pick up due to the increase of gas being sucked in.

To correct the problem, I pulled the carbs off the boots and sealed the head to intake boot with some high temp silicone. Runs like a charm now!

Gotta say, I like a little popping though. Within reason of course.

Thanks to all,I'm pullin the carbs tomorrow,I see what looks like a crack on #3 holder on the inside with a mirror.I'll keep ya posted

Your Russ Collins exhaust, does that say "RC Engineering" on the plaque on the muffler?

Yes it does.

Performance Products

Decel popping can also be a bad cyl head to pipe exhaust gasket seal. I've also seen rust holes in the exhaust cause popping. I had a cheap MAC exhaust on my GS1100E that had an annoying decel pop, and I finally ended up running double copper crush gaskets in the head and popping was eliminated.

Thanks, but I've already been down that road,that is was I thought it was at the begining and replaced all crush gaskets with new ones and cleaned the head and header flange.I pulled the carbs off yesterday and sure enough #3 carb holder has a crack in it time to replace um, we'll see what happens next week when I get it back together.