Sounds interesting,

Far to technical for me, If you dont have a laptop do you have to go to the dealers ,or a dyno shop ?

Either way I can hear the "Kaaaaachiiiiiing" !!! of a cash register!

Do these mods really make that much of an immprovement?

Nige

 

Angry Monkey,

Lets work together on this because the instructions of the SERT seems to contradict what everybody else is doing to reduce burble and popping on a tuned map. Kenny pointed this out on the phone the other day (thanks Kenny) Decreasing the value, you are actually richening up, not removing fuel. And the added burble is certainly due to far richer mixture especially after hammering the bike. The added fuel is burning off in the headers. Its just 'cosmetic' but I think this should be easy to tune out to a degree by raising those values in the deceleration enleanment table instead of going lower. I'm working on this today (right now actually) so we should compare notes on where these values actually end up. I'm ready to load up a modded map and try it out tonight.

Otherwise, I only get popping when I really hammer the bike through the gears and abruptly close the throttle. We have to be careful adjusting this because we don't want the fuel to cut off too much in these conditions.... I'm going up 2-5 units to start with as a test. I'll post my testing on this tommorrow or later tonight but I'm not going to go crazy over it. Some popping and burble (a good thing) on deceleration is perfectly normal on any bike carbed or EFI but exagerated slightly on bikes with an exhaust crossover.


Deceleration Enleanment (DE)

The Deceleration Enleanment table adjusts transient fuel removed when the throttle is closed and the vehicle is under deceleration. This is used to prevent 'popping' in the exhaust.


Note: Larger values in this table cause more fuel to be Removed when DE mode is active - i.e. the AFR will be leaner!

¡ Increments increase fuel Removed from the engine at a given temperature.

¡ Decrements decrease fuel Removed from the engine at a given temperature.

 

FL,
Here's what my manual says:

Decel exhaust popping is combustion occurring in the exhaust. Since combustion occurs over a narrow range of A/F ratios, popping can be cured by either richening or leaning the unburned mixture in the exhaust so it cannot combust.



Here's some info I was looking at:
"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....."

 

I'm very familiar with that technique.

What those guys are doing is adding even more fuel through additional VE value/lowering DE value and giving their header pipes a 'gas bath' to cool the header so small combustion won't occur inside a hot header pipe. It does work and they're not wrong if popping bothers them that much. But look at it this way. On a non constant velocity slide carburated bike (i.e. Mikuni's and Amal's), what happens when you close the slide? It abruptly cuts off fuel and switches to the pilot/idle curcuit. In this circumstance, the bike is trying to get down to idle speed as quickly as possible. Explains why my FI bike has less compression braking then my old Shovel or EVO. Much less. Why would we add fuel to this process? Read those posts some more and find that some of them have not solved their problem and report a strange surge or spike at 2000-2500 RPM's during decel. Think extra gas just might be causing that?

I've yet to see a post where anybody raised the decel enleanment table.

What we have is a well tuned map. I smell no gas from the exhaust, throttle response is crisp and top end superb. There is no surging and lots of power throughout the RPM range. So the map and fuel delivery where is counts is very good. The VE's are already set (not guessed) and the timing is already several degrees higher then the factory map. It got a bit late so I'll have my results tommorrow. The modded map with higher DE values is loaded and ready to go.

 

How much did you add to the DE??

 

PM message comming....call me.

 

Hey FL_799, I hope you're ready to help me once my SERT finally shows up.

 

Power,
We are trying to fine tune it now.....

 

Hey guys,


I just got my bike back from the dealler. He installed the 25 degree injectors under warranty an downloaded program 141nw102. This is the new map for a 1550 cc stage 2 with SE2 slip on exhaust. My dealer even GAVE me the g version of the calibraions for the sert. My dealers is awesome and knows the 2 words customer service, and it's not the dealer I bought my bike from.
He gives me no hassles about recalls, upgrades and there's never talk about vioding any warranty. There are awesome dealers out there. You just have to look for them.

Anyway the bike now hauls and does roll ons with tremendous ease. It's what I wanted from the start.


THere is still decel popping ,However not as much as before. The bike runs great everywhere except for the popping . THis shoundn't be a major issue.

When I really gun it and then let off it doesn't pop. It pops when I decel after normal riding which tends to make me think I need to add not subtract to the deleanment table .

FL 799 was right . It's going to be some trial and error for a little bit. I hope it's not major and it shouldn't be because the bike runs awesome except for minor to moderate popping on decel.

I look foward to anyone's input on this

 

Kenny,

Glad to hear you got squared away and the 1550 St 2 is hauling A$$.

Like you said. I think eliminating the popping will be hit or miss by adjust ing that decel enleanment table one way or the other. Going rich(er) on decel will fix it, no doubt about that. I think there might be a better way. We'll know today!

The inside of my Baloney cut pipes tells a good story. When the bike was running the factory stage one/lean doanload, the inside of the pipes had very little 'combustion soot' and the bike never popped either. The plugs were dangerously white. The only time I saw soot on the exhaust is when it was on the dyno doing WOT runs in Daytona; still didn't pop or burble on decel.

With this new map, the plugs look much better color, and I have more healthy looking deposits in the pipes but more burble and the occassional pop. I'm goin' up on that table. Map is loaded on the bike and ready to go today. I went up 5 units. It might not be enough. I did see a few dyno tuned maps where the units were raised up to 20-25 units so I know there is some room for adjustment.

But I'm not going to go nuts on this. My '99 EVO (Kehin CV) and '79 Shovel (Mikuni VM) were tuned to perfection and burbled occassionally popped on decel so it's par for the course on a tuned bike.

For your issue, just some thoughts; all of the HD canned maps are actually programmed RICH at WOT if you can believe that. With production bike variance in head CC's and combustion ratio's that there is no room for [lean] error at WOT. Might explain the lack of popping since the extra fuel is cooling the header or squashing header combustion. The first thing these guys do when they tune the SERT for max HP/tq is lean out the top end. Could be worth tinkering with the VE tables to find out. The Map Angry Monkey and I are running is leaned out up top and runs like a bat out of hell for a 1450. Put off my need to do a 1550/TW26's for a little while anyway.