dougl

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If the bike is otherwise running smoothly, you probably don’t have a vacuum leak. Assuming no other leaks, you could try an experiment. The F/L switch is 4% throttle in the stock tune. If you set it to zero, the main F tables will be used down to 0% throttle. Decel pop is at 0% throttle. Popping on my RIII occurred between about 2000 and 4500 rpm. So trim up (as a percent) the F fuel values in the 0% TP column starting at +10% at 2000 (don’t want to interfere with the idle) to 15% at 4500. Add more if it still pops. This is what is commonly done with Power Commanders. Potential problems are that you may lose some smoothness in the throttle up to 4% and the O2 sensor could lean out what you added. Does the DNK tune change the F/L switch? I’d like to see what she did if someone wants to send it. I don’t have a Rocket so I wouldn’t be using it.
 

nas6208

.020 Over
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Nov 24, 2020
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south central Kansas
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I’m surprised you can hear popping with the mufflers and cat. The older R3 with TORs and cat bypass popped loudly on decel with the stock tune for that exhaust. My full Jardine exhaust was ridiculous. The popping is caused by a lean condition where the fuel ignites in the exhaust. This was a difficult problem to address because: 1) fueling at zero throttle under load is based on manifold pressure (MAP) - you can add fuel to the L tables but you have to know the range of rpm and MAP over which popping occurs; and 2) in closed loop, fueling tends to get leaned even more.
dougl,
It is subjective for sure, but I'm hard of hearing and wear ear plugs. If I can hear it and think it might be objectionable to others, I will try to minimize or eliminate it. The popping (some call it a burble) at upper rpms is not really objectionable all the way down to around 2500 rpm. Below 2500, and with a completely closed throttle, is when it becomes a bit louder with more distinct pops. If I crack the throttle just a tiny bit, it stops. So it seems it needs a small amount of fuel in that region?
I'm familiar with TTS Mastertune map tables from my HDs, but just starting to learn TuneECU and KeiHin controls (not much info out there compared to HD).
Paul
 

dougl

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Reno, NV
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dougl,
It is subjective for sure, but I'm hard of hearing and wear ear plugs. If I can hear it and think it might be objectionable to others, I will try to minimize or eliminate it. The popping (some call it a burble) at upper rpms is not really objectionable all the way down to around 2500 rpm. Below 2500, and with a completely closed throttle, is when it becomes a bit louder with more distinct pops. If I crack the throttle just a tiny bit, it stops. So it seems it needs a small amount of fuel in that region?
I'm familiar with TTS Mastertune map tables from my HDs, but just starting to learn TuneECU and KeiHin controls (not much info out there compared to HD).
Paul
See my post above. This is a difficult problem to deal with without a Power Commander and not being able to disable closed loop.
 

nas6208

.020 Over
Joined
Nov 24, 2020
Messages
19
Location
south central Kansas
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2020 R3GT
If the bike is otherwise running smoothly, you probably don’t have a vacuum leak. Assuming no other leaks, you could try an experiment. The F/L switch is 4% throttle in the stock tune. If you set it to zero, the main F tables will be used down to 0% throttle. Decel pop is at 0% throttle. Popping on my RIII occurred between about 2000 and 4500 rpm. So trim up (as a percent) the F fuel values in the 0% TP column starting at +10% at 2000 (don’t want to interfere with the idle) to 15% at 4500. Add more if it still pops. This is what is commonly done with Power Commanders. Potential problems are that you may lose some smoothness in the throttle up to 4% and the O2 sensor could lean out what you added. Does the DNK tune change the F/L switch? I’d like to see what she did if someone wants to send it. I don’t have a Rocket so I wouldn’t be using it.
thanks dougl,
I will let DNK have a crack at it again as they offer free support for 30 days. I have to admit that if it is not a straight-forward fix, it will be difficult for them to eliminate without running it across a dyno where their changes can be seen in real time.

Is the F/L switch where it goes to closed loop using the O2 sensors? The older Fuel Injected Harleys were closed loop up to 60%-80% throttle position (depending on rpm), then just went to open loop (tabular data) above that. Anyway, what are 'F' and 'L' tables and what parameters or sensors are they using to control fuel?
Thanks,
Paul
 
Last edited:

nas6208

.020 Over
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Location
south central Kansas
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2020 R3GT
".....The F/L switch is 4% throttle in the stock tune. If you set it to zero, the main F tables will be used down to 0% throttle. Decel pop is at 0% throttle. Popping on my RIII occurred between about 2000 and 4500 rpm. So trim up (as a percent) the F fuel values in the 0% TP column starting at +10% at 2000 (don’t want to interfere with the idle) to 15% at 4500. Add more if it still pops. ...."
See my post above. This is a difficult problem to deal with without a Power Commander and not being able to disable closed loop.
If it only is popping objectionably below 2500, and only with a completely closed throttle, what would happen to idle if I added 10% more fuel to the 0% throttle position cells below say 2500 rpm?
 

dougl

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".....The F/L switch is 4% throttle in the stock tune. If you set it to zero, the main F tables will be used down to 0% throttle. Decel pop is at 0% throttle. Popping on my RIII occurred between about 2000 and 4500 rpm. So trim up (as a percent) the F fuel values in the 0% TP column starting at +10% at 2000 (don’t want to interfere with the idle) to 15% at 4500. Add more if it still pops. ...."

If it only is popping objectionably below 2500, and only with a completely closed throttle, what would happen to idle if I added 10% more fuel to the 0% throttle position cells below say 2500 rpm?
The F/L switch is the throttle % where it switches from using MAP vs rpm (L fuel tables) to Throttle Position vs rpm (F tables). It has nothing to do with the O2 sensor.
Sounds like the popping happens just as you’re stopping. Adding fuel to the F tables at 0 throttle won’t do anything with the F/L switch set to 4%. You’d have to reset those values to zero. Don’t get too close to idle rpm - you could mess it up, I would guess for cold start idle.
 

dougl

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There’s also the O2 sensor problem. You could raise the fuel by 10% and the O2 sensor in closed loop could lean it back to where it was. I’m not sure if the ECU would use closed loop when the rpms are decreasing rapidly. With a PCV and O2 sensor eliminator, you don’t need a dyno to deal with this. Unfortunately, there is no PCV yet and good luck finding the eliminator plug. If it was the same as the old Rockets, you can get one from the UK on eBay. Not sure if the connectors are the same or the ohmage. of the heater and sensor resistors.
 
Last edited:

nas6208

.020 Over
Joined
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south central Kansas
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2020 R3GT
The F/L switch is the throttle % where it switches from using MAP vs rpm (L fuel tables) to Throttle Position vs rpm (F tables). It has nothing to do with the O2 sensor.
Sounds like the popping happens just as you’re stopping. Adding fuel to the F tables at 0 throttle won’t do anything with the F/L switch set to 4%. You’d have to reset those values to zero. Don’t get too close to idle rpm - you could mess it up, I would guess for cold start idle.
thanks dougl.
Speaking of cold start idle issues, I noticed for the first time the other day that the cold start fueling is different from the stock map. I often ride in weather down to 20-25F and noticed on a cold start the other day rpm hanging at about 1500 rpm for several minutes. Under the same conditions with the stock map rpm would rise to around 1500 on startup, but slowly decrease down close to nominal idle speed of around 1000-1100 rpm in less than 1 minute . Never did that with the stock map, so maybe they got a little too close to idle values when enriching?
The stock map was perfect everywhere - except for the popping. Maybe it won't be so easy to improve on the stock tune after all.
 

nas6208

.020 Over
Joined
Nov 24, 2020
Messages
19
Location
south central Kansas
Ride
2020 R3GT
There’s also the O2 sensor problem. You could raise the fuel by 10% and the O2 sensor in closed loop could lean it back to where it was. I’m not sure if the ECU would use closed loop when the rpms are decreasing rapidly. With a PCV and O2 sensor eliminator, you don’t need a dyno to deal with this. Unfortunately, there is no PCV yet and good luck finding the eliminator plug. If it was the same as the old Rockets, you can get one from the UK on eBay. Not sure if the connectors are the same or the ohmage. of the heater and sensor resistors.
I can see where the O2 sensor and closed loop could offset any small changes one would make. I need to find out more about the Keihin ECU works. The older HDs controls (Delphi) were using RPM vs. engine load relationship (speed-density) to determine fuel and spark mapping and (it seemed to me anyway) pretty straight forward.
 

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