Modern Vespa

Can anyone explain to me why scooters do this? I had the same issue on my Vespa Sprint but the BV is doing it a lot more.

Is there a way to resolve this issue without going for a service at the dealer?

Thanks
H.

The only time I had backfire issues was before I had the mapping software on the commuter scooter updated. It backfired after riding the slab. I'd hit the off ramp and pop, pop, pop. It popped a few miles and stopped. Wouldn't pop until I rode the slab again.

Backfiring is ignition coming out the air intake. You're not getting that are you?
Many scooters burble out the exhaust which sometimes sounds like muffled backfire. My Vespa, BV350 and Kymco People 250 make these sounds. YMMV

The popping is coming from the exhaust ... its happening on any type of deceleration. I had the mapping update done recently and noticed a lot more popping ...

Any ideas how to make it stop or at least less often. Its just annoying.

Good to know; my BV350 is doing the same! The popping is pretty soft, so I guess that's it.

The increase in popping is due to an excess of unburned fuel entering the exhaust system and lighting. The aftermarket "box" is injecting fuel that's not burned during combustion.
Some noise in the stock system is resonation. There's a noise generated from sound reflecting in the exhaust system.

What is the "the slab"????

My BV tends to do it in the warmer weather, I notice it more when sitting in heavy traffic. It seems the stop and go in the 75 degrees + weather makes my fan cycle often, it pushes my temp gauge to the center. It will pop on decel. Then even if I get a good stretch of non stop it still pops but noticeable less.

My guess is you guys are in warmer climate than NYC.

John

Was this an OEM software update or a tuning/non-OEM software?

In general, the amount of un-burned fuel through cylinder depends on the correct orchestration of the amount of in-coming fuel, timing and quality of ignition and flow of fuel through the cylinder (cam & valves). The combination of fuel injection & ignition has a lot to do with this - so without knowing anything about BVs, I would say the new "mapping" is the one to blame. Especially if you noticed a change immediately after this.

Racing cars and bikes typically pop like grazy, especially when decelerating, because the fuel burning is tried to optimize/maximize for the task. They don't have exhaust catalyzers etc. to worry about, nor overall fuel economy etc.

If possible, I would start by going back to where ever you updated the mapping and see if any further fine tuning could be done.

The slab is a term for Interstate highways.

I had it done at the dealer so I would think its an OEM update. Funny today the popping sound was non existent. Wonders never cease.

Running a BV350 in South Florida I've found it's often popping on deceleration. It was mildly annoying enough that I asked the local dealer about a remapping (I read about it on another thread), and if that would eliminate the issue? Service manager suggested leaving well enough alone, concerned we might change something else unintended, for the worse.