Idle and Decel Backfire
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Cruiser
Joined: Apr 2010
Posts: 128
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From: Louisville, KY
Idle and Decel Backfire
I asked this question on another thread but was told that I would get better information if I posted in the specific thread. So here it goes.
I bought a 2001 Road King Classic with 53,000 miles on it for 9500. The bike is gorgeous! And on the test ride I had no issues at all, I assume this was because I was easy on it and thats just not my normal riding style.
Here is a video of the bike running. http://www.youtube.com/watch?v=PHdyh6XcDSk
Well on the way home on the interstate I noticed when I let off the throttle quickly, and decel brake I will getting some poping in the exhaust. (See video) The bike has generic slip on pipes. (See photos). I dont know of any fuel management system thats on the bike currently but then again I dont know if the issue really lies in it. The slip on pipes seem to have quite a bit of baffling compared to free flowing pipes this bike sounds like a mouse. Is there anything I could check as an amateur mechanic? Or should this be left for a dyno and a professional?
Also, does my idle sound rough? It sounds like the cylinders are firing in like a 1-2-1-2-1-1-1-2-1-2-1-1-1. Is this the normal sound for these tc88s?
Thanks.
I bought a 2001 Road King Classic with 53,000 miles on it for 9500. The bike is gorgeous! And on the test ride I had no issues at all, I assume this was because I was easy on it and thats just not my normal riding style.
Here is a video of the bike running. http://www.youtube.com/watch?v=PHdyh6XcDSk
Well on the way home on the interstate I noticed when I let off the throttle quickly, and decel brake I will getting some poping in the exhaust. (See video) The bike has generic slip on pipes. (See photos). I dont know of any fuel management system thats on the bike currently but then again I dont know if the issue really lies in it. The slip on pipes seem to have quite a bit of baffling compared to free flowing pipes this bike sounds like a mouse. Is there anything I could check as an amateur mechanic? Or should this be left for a dyno and a professional?
Also, does my idle sound rough? It sounds like the cylinders are firing in like a 1-2-1-2-1-1-1-2-1-2-1-1-1. Is this the normal sound for these tc88s?
Thanks.
Club Member
Joined: Aug 2007
Posts: 10,393
Likes: 2,060
From: N. Atlanta Burbs
Your bike has an Magneti Marelli fuel injection on her. This was only used for a couple of years (1999-2001) by HD until the Delphi was introduced. A tuner used to be available for them via the SERT but they don't make it anymore. The part number is or was 32107-01E
The idle for an MM system has given many an owner fits and there is an idle screw on the throttle body but you have to dig it out from the gum cap. I recommend leaving it alone. I've also witnessed air leaks at the heads with them as a normal reality. Your decel pop could be caused by several issues. Vacuum leak at the throttle body, exhaust leak at the head or exhaust joint or a lean condition during deceleration in zero throttle.
The main issue is simply the MM system is obsolete but there is still hope. The people that made the SERT are called TTS. I believe they still make a TTS for the MM. Power Commander also made a PCIII for the MM that may still be available. Why am I telling you this?
To get your beauty running as it should you will need to seek out a good fuel management system to settle your idle and decel pop once you make sure your throttle body vacuum leak has been resolved. (if it has one). She will then wake up and make you a happy camper. You can enrich the zero throttle positions between 1750 to 3500 to stop a decel pop if it is caused by a lean condition or exhaust reversion.
It is very possible that the previous owner of the bike used a PCIII but removed it before it sold. Looking at your plugs... they don't look too bad so I'm willing to stick my neck out and say this.
The idle for an MM system has given many an owner fits and there is an idle screw on the throttle body but you have to dig it out from the gum cap. I recommend leaving it alone. I've also witnessed air leaks at the heads with them as a normal reality. Your decel pop could be caused by several issues. Vacuum leak at the throttle body, exhaust leak at the head or exhaust joint or a lean condition during deceleration in zero throttle.
The main issue is simply the MM system is obsolete but there is still hope. The people that made the SERT are called TTS. I believe they still make a TTS for the MM. Power Commander also made a PCIII for the MM that may still be available. Why am I telling you this?
To get your beauty running as it should you will need to seek out a good fuel management system to settle your idle and decel pop once you make sure your throttle body vacuum leak has been resolved. (if it has one). She will then wake up and make you a happy camper. You can enrich the zero throttle positions between 1750 to 3500 to stop a decel pop if it is caused by a lean condition or exhaust reversion.
It is very possible that the previous owner of the bike used a PCIII but removed it before it sold. Looking at your plugs... they don't look too bad so I'm willing to stick my neck out and say this.
Thread Starter
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Cruiser
Joined: Apr 2010
Posts: 128
Likes: 0
From: Louisville, KY
Thanks for the reply man. I just dropped my bike off at a indy mechanic my uncle sent me to. He is going to look through the bike and check for anything unusual, including a leak down test. I am also looking for a PCIII for my model bike and am going to install it asap. I just bought a manual so I can do some of my own wrenching aswell.
Thanks again! Very good information for me.
Thanks again! Very good information for me.
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