Need Help with Decel pop on dyno tune

[Grillfish]

ADMINs: One idea.. can this topic be merged with the SEPST thread we have? This is great conversation and IMO might be best in that one thread. Thanks!

 

[Hoople]

One other thing just came to mind that I forgot to ask from the very beginning,, and that is the type of exhaust pipe flange design you have on your header pipes and the type of wire mesh gaskets used at the cylinder head. I understand that there are two types.

I had the "Taper Cone" type. That is the type where the header connection is somewhat of a "ball socket".
The other is a "Square Cut" design. If you happen to have the square cut design, I would think your chances of NOT having a leak is much better. The wire mesh seal is shaped like a quad ring used on a piston in a brake caliper.

On my 2009, the stock factory header pipes were the taper cone type. I had to wrestle with mine. I would have liked to have the square cut/quad seal design myself.

 

[NewtoHD]

Some ideas on what I changed for the same situation.

1) Save the map that they installed on your laptop. you paid good money for it and you do not want to loose it.

2) Copy that map with a new name then....

3) assuming your VE tables are calibrated properly (and they should have after the dyno) drop your AFR table in the 20 MAP collum (farthest left) from 4K down to 1250K. I dropped mine down to 13.8. This should help the decel pop when you have the throttle closed (not turning it) and the engine is braking.

4) go into your decel eleanment table (this adjusts the volume of fuel when closing the throttle (i.e. when you shift) and either increase it (reduces the fuel when closing) or drop it (increases fuel when closing). I decreased mine slowly until it stopped.

5) What is your AFR map look like? I've noticed if your idleing at 14.6, and you take off, the exhaust is so hot it ignites in 1 to 2nd gear shift (pops). I'm only running closed loop for my cruise range (1250 to 3000 from 30-70 MAP). Still getting solid 42 mpg.

6) I also changed timing to what the canned map was from the SEPST program and that helped, but the dyno guy should have adjusted timing as well as all other aspects of the map when your bike was dynoed.

Hope this helps...

It does, I have read as much as I can find and you have several good ideals I have used. My entire AFR table is less than 13.2, the tuner set idle at 12 up to 1500 rpm and 13.2 the rest of the way up. I have compared the canned map the SEPST software has with it to my "dyno" tuned map, the only thing changed is the AFR map and about 20 VE cells, nothing else is changed from canned HD map. This afternoon I cut the decel in half and bumped the VEs in the area of the pop by 10 and it seems to cut my poping in half. Maybe prgress.

I still need to do a professional check of my exhaust to make sure I do not have a leak causing the problem. Will see if I can smoke test as Hoople suggests. The dealer stated they used new flange gaskets but there was no charge on the ticket for any gaskets, so I may indeed have a leak if they reused the old ones.

 

[NewtoHD]

Fixed my poping, took it to a indy tuner for a new dyno tune. Stealer visited 3 times, kept telling it is running ok.