Popping on Deceleration

Gregger

Living Legend
Joined
Nov 2, 2013
Messages
2,435
Location
Timmins, Ontario
Ride
2012 Rocket Roadster
Gents,

With carbed bikes, we got rid of popping on deceleration by richening the idle mixture and getting rid of Air Injection devices. How can we do this with the Rocket? I'm running 20355 tune for a stock 12 Roadster with TORs. The restriction on the secondary throttles in the first 3 gears has been removed. The bike has always popped on deceleration.

I looked at the tune and noticed that for around the first 15% of throttle opening, the A/F ratio is set at 14.50 to 1 until you hit 4000 rpms. Would richening these a bit help with the decel popping?

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@Gregger. How often does the popping occur on your bike?

I'm running a similar setup (TOR + 3 pods for me) with the same tune as you. I use 91RON fuel. I get the occasional pop on decel, but not enough to cause me any concern. If I ride the bike 5 days/week I probably only hear the pop a couple of times.

On my bike the pop was there before I opened the secondary throttles. After derestricting the bike the pop is still there, but no better or worse.
 
If you search here on Deceleration Popping you will find a post by Hanso where he says to add a little fuel to the Zero (0) column of the "L" tables.
I am running a PCV and was basically told the same thing by the techs at Power Commander... to add a bit of fuel to the Zero column... I bumped mine (in the power commander) from 0 to 10 and the popping was all but gone.. So I would say your assumption to richen the idle mixture is correct...
 
Mine pops a little bit here and there, but I kinda like it. It reminds me of a growling bear.

I have the aftermarket pipe tune loaded by the dealer with D&D slipons. I had an actual backfire once before I recrimped my leads and it scared the bejeezuz out of me. It came out the left side right at my leg while I was out for a test ride with no bearclaw on... BOOM! But the little pops don't bother me. Once my ecu cable finally comes, it will be fun to tinker.
 
@Gregger. How often does the popping occur on your bike?

I use a lot of engine braking while stopping. Love the sound. Not a lot of popping while braking in the higher gears, generally only in the lower ones. The popping takes place every time I engine brake though. Rarely get any backfiring that sounds like gunfire, just the poppy pop pop which to me sounds chinsy. Kind of like a 2 stroke ringadingdinging it's way to a stop. It really isn't a problem but with my America, I was able to virtually get rid of it.
 
the popping can usually be tuned out to some degree if not completely by adding fuel in the L tables.
I was told the popping is not really harmful so long as it is not a full blown backfire.
Anybody that is not confident of adding the fuel in the zero column of the L tables via Tune ECU is welcome to drop me a "conversation" with their e-mail address so we can send the .Hex file back and forth between us, please include bike details I am happy to do this
 
This is the result of a lean condition at zero TP. Adding fuel to the bottom of the L tables should help but only if the O2 sensor is disabled. If it isn't the sensor will cause the ecu to lean out any changes you make to the L tables. This is analogous to installing a Power Commander, which takes out the O2 sensor and can be used to tune out the decel popping.
 
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