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[sefatboyscott]

They only charged you a little over an hour for a dyno tune? SWEET!

[tunedse2]

No, they charged me 1.2 for pipe installation. 2.5 on top of that for the tune.

[sefatboyscott]

Actually they overcharged you for the install then. I changed my pipes myself it took a half hour tops........4 bolts each pipe! But you got a great deal on the tune so it balances out. Took them 4.5 hours to custom map my bike on the dyno.

[TankerPig]

I just had a set of V&H Big Shots Staggered installed on my bike and am experiencing that popping sound upon deceleration also.  From what I understand from everyone, this is largely due to the AF mixture and can be cured with a new computer map and a dyno tune.  My dealer told me they "remapped" the engine after installing the pipes, but after speaking to a chopper shop owner near me, he explained that H-D simply sets up the computer to be remapped as opposed to actually remapping the engine for the new pipes.  Has anyone else heard of this before?  Or am I being fed incorrect info?

[tunedse2]

Tanker my Bike is in the shop for that problem right now. I have talked to several different tuners
and everyone has an opinion. Some say exhaust leak some say tune, Stay tuned I had a thread entitled popping Big Radius that I will post the results to in the next 3-4 days. I was real close to paying for another tune and got so pissed at the thought that I called the owner of the dealership to inform him of my disgust and he asked me to give him one last chance and guaranteed me he would have it corrected. I will post the fix with Dyno sheets ASAP.....

[TankerPig]

Just spoke to the head mechanic at the local H-D and asked about the popping sound during decel and down-shift.  He told me that the popping sound is normal with aftermarket pipes, particularly V&H, and I shouldn't be concerned about it.  The only time I should be concerned about that sound is if it happens during acceleration.  I asked him about possible engine damage in the long run and he said there would be none.  He told me I could lessen the popping with a dyno tune, but the cost isn't worth the effort.  Still concerns me, regardless.  

[grc]

I just had a set of V&H Big Shots Staggered installed on my bike and am experiencing that popping sound upon deceleration also.  From what I understand from everyone, this is largely due to the AF mixture and can be cured with a new computer map and a dyno tune.  My dealer told me they "remapped" the engine after installing the pipes, but after speaking to a chopper shop owner near me, he explained that H-D simply sets up the computer to be remapped as opposed to actually remapping the engine for the new pipes.  Has anyone else heard of this before?  Or am I being fed incorrect info?

Tanker,

Do you have a SERT or PowerCommander?  If not, what the dealer did was download the Stage (?) calibration to your ECM.  The "Stage" calibrations are for Screamin' Eagle pipes, and will not be optimized for your V&H pipes.  If you have a SERT or PC, then a good tuner should be able to remove fuel on decel to reduce or eliminate the popping.

BTW - I had a set of the staggered pipes on my previous bike (Super Glide Sport), and absolutely loved them.  Excellent appearance, sound, and performance with the Power Chamber crossover.  The bike was carbureted, so on decel from high rpm's it did pop some, but not on normal low speed decel or on shifts.  If you removed the baffles, try putting them back in.  That will also make a difference.

Jerry

[TankerPig]

Wow.  The sheer amount of information one can get from this forum is staggering.  I've tracked several threads regarding the same topic.  Seems like the trick is to get either the SERT or the PC and finding a tuner who will do the job right.  Does anyone know for sure if the Harley warranty will necessitate me using a SERT? Or can I go with a PC, which seems much more flexible in terms of downloads and tuning (with regards to John Golden "the dyno guy" prefering to work with PC only).  Any recommendations will me appreciated (I'm learning something new everyday  ).  I'm quickly losing faith in my local H-D service department.  I'm getting much more useful information from everyone here.  I would have thought this would be information the service mechanics would have talked to me about when they were installing the pipes and the generic download.

[hd-dude]

Tanker;
The use of the PC will NOT void your warranty in any way. Use it and enjoy, Especially if that is what your tuner is familiar with and uses [smiley=xyxthumbs.gif]

[RJ749]

Just spoke to the head mechanic at the local H-D and asked about the popping sound during decel and down-shift.  He told me that the popping sound is normal with aftermarket pipes, particularly V&H, and I shouldn't be concerned about it.  The only time I should be concerned about that sound is if it happens during acceleration.  I asked him about possible engine damage in the long run and he said there would be none.  He told me I could lessen the popping with a dyno tune, but the cost isn't worth the effort.  Still concerns me, regardless.  

In another post the popping is explained as cold air rushing into the exhaust on decel and is normal.  I get the same thing on my truck with mod exhaust.

[grc]

In another post the popping is explained as cold air rushing into the exhaust on decel and is normal.  I get the same thing on my truck with mod exhaust.

Rjob,

The real reason you get popping on decel is that when the throttle plate is closed, you get insufficient air to burn the fuel in the combustion chambers.  Thus you get unburned fuel in the (hot) exhaust system.  Since you cannot eliminate the air in the exhaust system, the best way to eliminate the popping is to eliminate the unburned fuel.  Unlike with carbs, EFI makes this a relatively easy solution.  The stock ECM is set up to reduce fuel on decel with the stock pipes, and you can feel the affect if you run the bike up to around 4k+ rpm in second gear and then chop the throttle.  You can hear the exhaust note change as you coast down, and it feels as if you are dragging the brakes.  Once the engine speed drops to a certain point, you will notice that the sound and feel returns to normal.  When you change pipes, the stock ECM strategy has to be changed to work with the new flow characteristics.  

Jerry

[RJ749]

Thanks Jerry.

I think the explanation of the air getting in there must come from the logic of it takes Oxygen to burn the unspent fuel but I'll go with your explanation as to the actual reason we get the pop.  

No fuel, no pop, regardless of whatever else is going on.

Off to rid myself of excess gas, I always hate it when I have it.