Decel popping
Big Kahuna HDF Member
Joined: Feb 2006
Posts: 23,881
Likes: 34
From: USA
RE: Decel popping
I have the same set up exactly and got it dyno'd at 1,000 miles. Now after the engine is a little older I took it back to have them tweak it even better. That's why I got the SERT. You can keep changing the tune.
FYI, I would buy the SERT before you spend the $$ on a dyno tune job.
FYI, I would buy the SERT before you spend the $$ on a dyno tune job.
Banned
Joined: Jan 2006
Posts: 17,265
Likes: 21
From: Los Angeles, CA
RE: Decel popping
I have v&h sideshots, a k&n a/f and some sort of download, and I get popping every once in a while. I am thinking about getting a pc3 or dfo, but it hasn't gotten bad enough to need that yet...
Road Warrior
Joined: Nov 2006
Posts: 1,561
Likes: 33
From: San Diego, CA
RE: Decel popping
ORIGINAL: jca_54
The Cobra company has an alternative to remapping your fuel injection. It is a plug in unit that has three adjustment screws (idle, mid and high rpm) and requires no computer downloads. I had one of these units on my old Vulcan Nomad and it worked like a charm. It totally eliminated backfiring on decel. You simply use the adjustment screws to enrich the fuel incrementally until your bike stops popping on decel. It is seat of the pants tuning but it worked very well for me. You can always pay for a dyno if you want to tweak it for maximum HP. It also gives you the ability to adjust as you change air intakes, mufflers, pipes, etc. and gets the dealer out of your pocket for future remaps. I planned to put one on my street bob but it was only recently that they came out with a closed loop unit that includes the plugs for the O2 sensors (I didn't want to jeopardize the manufacturer's warranty). I have one ordered and it should be in a week or two. I'll do a post in a few weeks and let you know how it works out.
John in Houston
The Cobra company has an alternative to remapping your fuel injection. It is a plug in unit that has three adjustment screws (idle, mid and high rpm) and requires no computer downloads. I had one of these units on my old Vulcan Nomad and it worked like a charm. It totally eliminated backfiring on decel. You simply use the adjustment screws to enrich the fuel incrementally until your bike stops popping on decel. It is seat of the pants tuning but it worked very well for me. You can always pay for a dyno if you want to tweak it for maximum HP. It also gives you the ability to adjust as you change air intakes, mufflers, pipes, etc. and gets the dealer out of your pocket for future remaps. I planned to put one on my street bob but it was only recently that they came out with a closed loop unit that includes the plugs for the O2 sensors (I didn't want to jeopardize the manufacturer's warranty). I have one ordered and it should be in a week or two. I'll do a post in a few weeks and let you know how it works out.
John in Houston
I look forward to your future posts as I discovered that I have a Cobra Fi2000 under my seat as well as a k&n a/f and BigGuns3 pipes on my 06 Low Rider. I bought it with 936 miles on it and it's my first Harley. I have logged about 800 miles on it myself and have learned a lot from hanging out here. I went to the web page and downloaded the manual for the Fi2000 but since I don't know what I'm doing and the bike seems to be running real well, I'm afraid to touch it. I was coming home on the I-5 today about 75-80 mph and when I let off the throttle, I heard a POP!! It wasn't super loud but it definately POPPED. It's only done it maybe 2 or 3 times in the past and I cannot duplicate the problem at will. Maybe I need to adjust one of the little thumb wheels but the pop is so rare?? I donno, You Tell Me???
Tourer
Joined: Sep 2006
Posts: 253
Likes: 0
From: Houston, Texas
RE: Decel popping
Gamma742,
You may need to increase the mid and/or high rpm (second and/or third adjustment screw) one number higher. It's trial and error. I would increase the second by one and try that, then the third by one if necessary. You could call Cobra and ask them what their recommended set up numbers are for your particular bike. I can tell you that when it's set correctly, you should have absolutely no popping on decel. I adjusted the one on my Vulcan in the garage by simply revving the bike up to about 2000 - 2500 RPM and holding it there for a few seconds, then releasing the throttle back to idle. I just kept doing that and adjusting up one number at a time until the popping stopped. Once I got it right, I couldn't get it to pop or backfire if I tried. Keep in mind that as you increase fuel, it will have an effect on gas milage so you should increase in small increments and not go higher than necessary to alleviate the popping on decel. Hope this helps.
You may need to increase the mid and/or high rpm (second and/or third adjustment screw) one number higher. It's trial and error. I would increase the second by one and try that, then the third by one if necessary. You could call Cobra and ask them what their recommended set up numbers are for your particular bike. I can tell you that when it's set correctly, you should have absolutely no popping on decel. I adjusted the one on my Vulcan in the garage by simply revving the bike up to about 2000 - 2500 RPM and holding it there for a few seconds, then releasing the throttle back to idle. I just kept doing that and adjusting up one number at a time until the popping stopped. Once I got it right, I couldn't get it to pop or backfire if I tried. Keep in mind that as you increase fuel, it will have an effect on gas milage so you should increase in small increments and not go higher than necessary to alleviate the popping on decel. Hope this helps.
Tourer
Joined: Jul 2006
Posts: 380
Likes: 3
From:
RE: Decel popping
I run the PCIII with absolutely no problems to date. The bike runs great, seems that it wouldn't pop even if I try. The PCIII had a few things going for it over the competition in my opinion. 1st is the price. 2nd is the ease of installation and tuning. 3rd is the ability to go back to stock in a matter of minutes. 4th is the fact that my local stealer was very anti-power commander and very pro-SERT. Imagine that!! 5th is the fact that it has gotten so many good reviews and so few negative ones. 6th is the fact that is eliminates the O2 sensors. Yes that's right, I wanted to! If I wasn't happy with it I would most certainly speak up, but I am 100% satisfied with it up to this point.
Road Warrior
Joined: Nov 2006
Posts: 1,561
Likes: 33
From: San Diego, CA
RE: Decel popping
ORIGINAL: jca_54
Gamma742,
You may need to increase the mid and/or high rpm (second and/or third adjustment screw) one number higher. It's trial and error. I would increase the second by one and try that, then the third by one if necessary. You could call Cobra and ask them what their recommended set up numbers are for your particular bike. I can tell you that when it's set correctly, you should have absolutely no popping on decel. I adjusted the one on my Vulcan in the garage by simply revving the bike up to about 2000 - 2500 RPM and holding it there for a few seconds, then releasing the throttle back to idle. I just kept doing that and adjusting up one number at a time until the popping stopped. Once I got it right, I couldn't get it to pop or backfire if I tried. Keep in mind that as you increase fuel, it will have an effect on gas milage so you should increase in small increments and not go higher than necessary to alleviate the popping on decel. Hope this helps.
Gamma742,
You may need to increase the mid and/or high rpm (second and/or third adjustment screw) one number higher. It's trial and error. I would increase the second by one and try that, then the third by one if necessary. You could call Cobra and ask them what their recommended set up numbers are for your particular bike. I can tell you that when it's set correctly, you should have absolutely no popping on decel. I adjusted the one on my Vulcan in the garage by simply revving the bike up to about 2000 - 2500 RPM and holding it there for a few seconds, then releasing the throttle back to idle. I just kept doing that and adjusting up one number at a time until the popping stopped. Once I got it right, I couldn't get it to pop or backfire if I tried. Keep in mind that as you increase fuel, it will have an effect on gas milage so you should increase in small increments and not go higher than necessary to alleviate the popping on decel. Hope this helps.
I downloaded this document http://www.cobrausa.com/pdf/692-1609CL.pdf and it looks like I should be set to 2.5 on the Green, 5 on the yellow, and 3 on the red switch. Looking at the last page of the document.
I going to go pull the seat off and check the settings.
brb
Tourer
Joined: Sep 2006
Posts: 253
Likes: 0
From: Houston, Texas
RE: Decel popping
The recommended factory settings may be based on stock air intake, exhaust, etc. Since you are running somthing different, you may need to increase the fuel slightly. I would just try it. You can always return to the previous settings.
Intermediate
Joined: Nov 2006
Posts: 28
Likes: 0
From:
RE: Decel popping
Gamma,
Set the Cobra FI up to it's stock settings. Now rev the bike up to 1800 RPM and hold it there while adjusting the green screw. The green screw is adjusted properly when the bike is running the smoothest. This takes care of your idle and cruise mixture. Now for midrange, set it to the manufacturers specs. Do the same with the red screw. Take the bike for a ride. If it pops on decel, adjust the green screw slightly to allow just a little more fuel in cruise mode. Give the bike a run. When it stops popping it's right. As far as midrange goes, how does the bike accelerate? Adjust the yellow screw for the best acceleration. I personally have never had to change it from the manufacturers recommended settings, same for the red screw. Popping on decel is usually related to the green screw setting. If it pops it needs just a little more fuel. Very similar to a carb on a car engine.
Remember, you can't mess it up cuz' you can always go back to the recommended settings and try again. It shouldn't take you more than one or two runs to fix this problem.
Set the Cobra FI up to it's stock settings. Now rev the bike up to 1800 RPM and hold it there while adjusting the green screw. The green screw is adjusted properly when the bike is running the smoothest. This takes care of your idle and cruise mixture. Now for midrange, set it to the manufacturers specs. Do the same with the red screw. Take the bike for a ride. If it pops on decel, adjust the green screw slightly to allow just a little more fuel in cruise mode. Give the bike a run. When it stops popping it's right. As far as midrange goes, how does the bike accelerate? Adjust the yellow screw for the best acceleration. I personally have never had to change it from the manufacturers recommended settings, same for the red screw. Popping on decel is usually related to the green screw setting. If it pops it needs just a little more fuel. Very similar to a carb on a car engine.
Remember, you can't mess it up cuz' you can always go back to the recommended settings and try again. It shouldn't take you more than one or two runs to fix this problem.