Tuning

Wadejesu said:

So DNK sent you a tune and still pops?

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Wadejesu said:

Right. A bit better and not as noticeable as before, but still there. I could live with it as it is now. I don't expect it to be completely fixed in one shot. I'll get back to them after I ride the bike a bit more.

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dougl said:

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.

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nas6208 said:

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

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dougl said:

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.

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dougl said:

See my post above. This is a difficult problem to deal with without a Power Commander and not being able to disable closed loop.

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nas6208 said:

".....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?

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dougl said:

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.

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dougl said:

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.

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