Made some changes still getting a pop.
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Stellar HDF Member
Joined: Jul 2014
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From: NC
Made some changes still getting a pop.
I picked up a set of after market slip on mufflers for my '96 RK that came off a '06 RK that are 4" and has an open baffle. These are louder and I did notice the bike felt better running the roads. I have a Dobeck TFI tuner installed as the '96 ECM is not programmable, I'm getting around 43MPG so I'm happy with that but here's the thing, I'm still getting what seems like a lot of deceleration popping. I replaced the intake gaskets and it improved but there is still a lot of decel pop.
I've been playing with this tuner but It doesn't seem to dial in completely. It seems to me it is running a little too rich.
I'm thinking of trying a newer tuner like the Cobra FI2000R but thought I'd check here first and see if anyone has any suggestions on dialing the Dobeck in better.
Thanks.
I've been playing with this tuner but It doesn't seem to dial in completely. It seems to me it is running a little too rich.
I'm thinking of trying a newer tuner like the Cobra FI2000R but thought I'd check here first and see if anyone has any suggestions on dialing the Dobeck in better.
Thanks.
Seasoned HDF Member
Joined: Feb 2007
Posts: 6,081
Likes: 1,127
From:
You report 4" open baffle.
Basically running huge wide open pipes, no baffle, no wrap, just an empty can and have ZERO back pressure.
Unless you have some special cams, special air box and several high performance additions then the only " feel " experienced should be noise.
The loss of back pressure probably reduced low speed torque too.
Only at extended wide open throttle rides would any actual performance improvement be measured and then only at full throttle after a while.
Air is entering your non-baffle pipes and combining with fuel that has not burned in the hot pipe causing small explosions.
A tuner change will not overcome that situation.
Adding more fuel will not tune it out.
If you want to use those pipes.
You may wish to consider a simple addition of muffler lollipops..home made would be fine and the cost is very easily under $10...basically eye bolts and two washers bolted together closing the eye...there are other ways depending on pipe diameter but you will get the idea.
They will add a little back pressure and then dial back the tuner (remove fuel).
If the bike is basically stock then consider running tuner near stock plus a little fuel at low end.
Here is a link that might help you understand.
http://www.nightrider.com/biketech/exhaust.htm
Basically running huge wide open pipes, no baffle, no wrap, just an empty can and have ZERO back pressure.
Unless you have some special cams, special air box and several high performance additions then the only " feel " experienced should be noise.
The loss of back pressure probably reduced low speed torque too.
Only at extended wide open throttle rides would any actual performance improvement be measured and then only at full throttle after a while.
Air is entering your non-baffle pipes and combining with fuel that has not burned in the hot pipe causing small explosions.
A tuner change will not overcome that situation.
Adding more fuel will not tune it out.
If you want to use those pipes.
You may wish to consider a simple addition of muffler lollipops..home made would be fine and the cost is very easily under $10...basically eye bolts and two washers bolted together closing the eye...there are other ways depending on pipe diameter but you will get the idea.
They will add a little back pressure and then dial back the tuner (remove fuel).
If the bike is basically stock then consider running tuner near stock plus a little fuel at low end.
Here is a link that might help you understand.
http://www.nightrider.com/biketech/exhaust.htm
Thread Starter
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Stellar HDF Member
Joined: Jul 2014
Posts: 2,721
Likes: 243
From: NC
Thank you for the information Im. These do have baffles in them but nothing like a restrictor plate across the opening. I was wondering if the lack of back pressure was a culprit. I figured if they came off a fuel injected '06 then they would work on a fuel injected '96. The opening is around 1-1/2" all the way through with a small bar stock running across. I'll see what I can do about the lollipops.
Stellar HDF Member
Joined: Jan 2009
Posts: 2,578
Likes: 463
From: On a Lake, not far from the Gulf
from an email I received from DynoJet:
Decel popping is caused by the detonation of unburned fuel in the exhaust pipe. This happens with high flow exhausts that allow more fresh air to be pulled into the pipe, causing the exhaust temperature to rise and detonate the fuel. Ways to reduce and possibly eliminate this popping are listed below and can vary between Harley-Davidson motorcycles and sport bikes and cruisers:
Harley-Davidson:
- For older Magnetti-Marelli fuel injected bikes, adjusting the fuel table to remove fuel can help reduce popping. Highlight the zero percent column from 2,000 rpm to redline and enter in values from -40 to -50. Run the bike and see if the popping has reduced. Sometimes, the throttle position may not show zero at idle and should be correctly adjusted with the bike at full operating temperature to make sure it is reading zero.
- On newer Delphi fuel injected bikes, we have found that adding fuel is needed to reduce popping. Highlight the zero percent column and instead of using negative numbers, try adding fuel to the map. Start with putting a value of 25 in the cells and see if the popping has reduced.
- Adjusting the ignition table could also help in deceleration popping. Advance the timing in the zero percent column 3 to 5 degrees to see if popping has been reduced.
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Joined: Apr 2011
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From: SE Louisiana
Ya, I should of maybe said try removing fuel first,
the experience I had was that you pretty much have to shut the fuel off for it to work, then it had a off/on feel when getting back on the throttle, adding fuel solved it. I guess it's trial and error.
Adding timing helps too
the experience I had was that you pretty much have to shut the fuel off for it to work, then it had a off/on feel when getting back on the throttle, adding fuel solved it. I guess it's trial and error.
Adding timing helps too
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Stellar HDF Member
Joined: Aug 2013
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From: Texas
I picked up a set of after market slip on mufflers for my '96 RK that came off a '06 RK that are 4" and has an open baffle. These are louder and I did notice the bike felt better running the roads. I have a Dobeck TFI tuner installed as the '96 ECM is not programmable, I'm getting around 43MPG so I'm happy with that but here's the thing, I'm still getting what seems like a lot of deceleration popping. I replaced the intake gaskets and it improved but there is still a lot of decel pop.
I've been playing with this tuner but It doesn't seem to dial in completely. It seems to me it is running a little too rich.
I'm thinking of trying a newer tuner like the Cobra FI2000R but thought I'd check here first and see if anyone has any suggestions on dialing the Dobeck in better.
Thanks.
I've been playing with this tuner but It doesn't seem to dial in completely. It seems to me it is running a little too rich.
I'm thinking of trying a newer tuner like the Cobra FI2000R but thought I'd check here first and see if anyone has any suggestions on dialing the Dobeck in better.
Thanks.
Seasoned HDF Member
Joined: Aug 2008
Posts: 5,080
Likes: 2,153
From: Ohio
I believe a Doebek is a 3 pot system and not able to break down cells like a Power Commander, the only chance you have is to tune it like a carb, add fuel in the lower rpms of the pots until it stops popping, shouldn't take much unless the baffles have been altered or packing is gone. then you need to punt the ball because your out of downs