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Discussion Starter · #1 ·
I've just fitted S&S SPO mufflers and a SE air cleaner to my 2002 Road King Classic and loaded map 105HM004. The bike runs very well and sounds great, with a low rumble that's too loud, but it does have some popping on overrun.
To address this I'm about to reduce the decel enleanment by 50%, as per advice given to others on this Forum. This is probably a silly question but in 105HM004 the decel enleanment values are uniformly .5, so is the adjustment I want as simple as reducing them all to .25?
I thought I'd also change the red cells in the AFR table to 13.9 again as per advice given to others - is it best to do these changes together or should I do them one at a time?
Thanks in advance for your help.
 

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I would do one thing at a time. Yes, if they are .5 half would be .25, it is that simple. I also have the SPOs on a 95" build and have taken the enleanment clear to 0, but still have some popping. I guess some pipes will pop no matter what you do.
 

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BOSS:

I agree with what sloxl is saying........try one thing at a time.

IMO, you should get familiar with Data Recording Mode and get some readings. A tach makes it nice to get a feel of where the decel pop is occuring.

Dropping the red AFRs to 13.9 is fine. But remember, the AFR Table is desired AFR. No way of knowing for sure what the actual AFR is without O2 Sensors or a dyno tune with sniffers.

Decel popping on long deceleration/coasting will usually improve with slight increases of the front and rear VE values at lower rpms in the O and 2% throttle columns. On my recordings decel enleanment had aready faded to 0 when the offensive popping was occuring.

HTH's till one of the experts here chimes in.

:cheers:
 

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Discussion Starter · #4 ·
Many thanks for your replies. On the basis of your comments my plan will be to: 1) drop the deleanment values to .25 from .5 first; then 2) if popping remains add 2.0 - 3.0 to the VE tables at 0 and 2% throttle from 1750.
From there if I still have popping do I further drop the enleanment values or further increase the VE table values?

My understanding is that altering the red cells in the AFR table to 13.9 is a change targeted at general running rather than popping, so I should leave that till last?? I'm just wondering as my experience with carbs has been that even though (for example) a main jet change is meant to only affect 3/4 throttle and above it actually effects the whole picture - but then I guess fuel injection mapping is a whole lot sharper tool than swapping jets!

I've got to say my considerable nervousness about doing all these things myself has been hugely reduced by reading this Forum and by your help - so thanks again.
 

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BSABOSS said:
Many thanks for your replies. On the basis of your comments my plan will be to: 1) drop the deleanment values to .25 from .5 first; then 2) if popping remains add 2.0 - 3.0 to the VE tables at 0 and 2% throttle from 1750.
From there if I still have popping do I further drop the enleanment values or further increase the VE table values?

My understanding is that altering the red cells in the AFR table to 13.9 is a change targeted at general running rather than popping, so I should leave that till last?? I'm just wondering as my experience with carbs has been that even though (for example) a main jet change is meant to only affect 3/4 throttle and above it actually effects the whole picture - but then I guess fuel injection mapping is a whole lot sharper tool than swapping jets!

I've got to say my considerable nervousness about doing all these things myself has been hugely reduced by reading this Forum and by your help - so thanks again.
If you really want to get rid of the decel popping add 5 degrees advance to both front and rear cyl in the 20 and 30 columns from 1250 to 3000 RPM. The highest vacumn will only be created on decel. Normal running ranges are above 30. This will draw the flame back into the cyl where it belongs, thus no popping in the pipes. Worked for me.......
 

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Let me say first that I am not the resident expert, only passing along what I have learned with my SPOs and Sert in the last month or so.

I forgot about the spark advance change, I did it with no adverse affects, but still have some popping. As I said earlier some pipes may have popping no matter what.

I would take the enleanment to 0 before I did anything else. Then the VE (or AFR) and finally the spark advance (no particular reason only that you completely use up one table before turning to the next one). The changes in enleanment, VE and AFR are all doing the same thing, adding fuel. There is no point in doing both VE and AFR, pick one and stick with it.

Using the Enleanment and then the AFR table means you do it once for each, the VE tables you have to do twice, once for each cylinder. If you can somehow figure out which cylinder is causing the popping then you could use the VE table for that cylinder. Not sure how you would do that though.

As MinesWide said the VE (or AFR) and spark adjustments for popping are done in the 20&30 MAP columns from 1250-3000 RPM (from memory here). The EFI is much more accurate than changing a needle!! If you change the 1000 RPM square you are not doing much since the bike is all but stopped by then anyway. Likewise any squares below or to the right of that area you are not decelerating.

As WVRDKING said get the dyno function up and running, but only if you have a wide open road with no 'roos to work on. It takes a well warmed up engine otherwise you have warmup fuel going in and that will throw all of your readings off. (10 minutes is not enough) You also need saddlebags or a real brave person to hold a laptop. Accelerate slowly up to 3rd gear, pause at about 2000 RPM and then open the throttle all the way and hang on. It'll scare the crap out of you the first time you do it. After you get stopped look for anti-knock activity, add fuel in those blocks (AFR). If you get anti-knock in the cylinders at different points then you will increase the VE in each cylinder instead of changing the AFR.
AFR=smaller number = more fuel, VE=larger number = more fuel.

The anti-knock function retards the spark in order to save the engine, which robs you of power. Adding fuel will help counteract knocking, but I wouldn't do a whole lot with this until you can get onto a dyno with somebody who knows what they are doing. On the other hand if you can make a couple of passes this way it will save you some dyno time.
Use small steps.
 

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If you really want to get rid of the decel popping add 5 degrees advance to both front and rear cyl in the 20 and 30 columns from 1250 to 3000 RPM. The highest vacumn will only be created on decel. Normal running ranges are above 30. This will draw the flame back into the cyl where it belongs, thus no popping in the pipes. I tried for almost 2 years to get rid of the decel popping and finally tried the advance thing, but I've got a ThunderHeader and they seem to cause more popping than most. I think they have better scavenging than most. I did all the other adjustments, the AFR, VE, Decel enleanment and they helped but couldn't get rid of all the popping till I did the advance thing. As a last resort I advanced it in those areas and it worked. So if a guy can't get rid of the popping I encourage them to advance the timing in those areas. Advancing in those areas won't hurt it because it's only on decel that the vacumn is high enough to change the advance, sucking the flame back into the motor where it belongs. I only do small changes at a time. All these motors run different for different people. What works for one may not work for another. It's more of a personal map than a general map. All you can do is tweak it till you get it right for you. I still need to wait for the hot weather to make sure it's right. The real test is how it works in the weather you'll be riding in the most. I may tweak some more but I'm real close now. All this is just my humble opinion as I'm not an expert, I just know what works for me.....
 

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Discussion Starter · #8 ·
Time to report back.

I began by reducing all of the enleanment table cells from .5 down to .25. That made a definite improvement, but there was still popping on gear changes and back off from about 3000 rpm.

So I reduced the cells down to .15 which further reduced but didn't eliminate the popping.

So I reduced the enleanment table cells down to 0, for a further mraginal improvement.

Next I moved to the front and rear VE tables and added 3.0 to all cells in the 0 and 2% throttle columns between 1750 and 6000. A further improvement but still some mild popping on gear changes and on backoff from middle revs.

So I added 5 degrees advance between 1250 and 3000 in the 20 and 30 columns. Again a marginal improvement but still some mild popping.

So from my starting point of very marked and quite loud popping I've reduced it to a stage where its still there but only very mild.

That's probably close enough for now as I'm going with an AMS 95" build in a month or so. By the way AMS are brilliant people to deal with and couldn't have been friendlier or more helpful to someone 10,000 miles away.

I'll also take your advice on the data logging (particularly the bit about picking a roo free piece of road for the runs). This SERT really is a great bit of gear, much better than mucking around with jets and suchlike!

Bill
 

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Angry_Monkey said:
Are you dropping the decel enleanment over the whole temp range?
Don't know who this question is aimed at, but I subtracted .25 from each cell at all temps. This richens up the decel helping to get rid of pop.
 
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