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[Jerry/MD]

When swapping-out a stock exhaust with true duals.... and not changing the EFI map? 

[dlaws01]

Most likely it running leaner causing higher engine temps,  but not sure. Based on year engine was made I think it can self adjust to a given amount.

[Jerry/MD]

Most likely it running leaner causing higher engine temps,  but not sure. Based on year engine was made I think it can self adjust to a given amount.

It's a 2003 FLHTC...which isn't mine.

[dlaws01]

Jerry,  when I had pipes put on my bike, the dealer said that I really didn't need SERT as the EFI would " self calibrate" to the fre'er breathing exhaust.  I went with the SERT and dyno tune anyway mostly to enrich the mixture and keep engine temps down.

[Jerry/MD]

Jerry,  when I had pipes put on my bike, the dealer said that I really didn't need SERT as the EFI would " self calibrate" to the fre'er breathing exhaust.  I went with the SERT and dyno tune anyway mostly to enrich the mixture and keep engine temps down.

Thanks for the feedback. IMHO it is safer to re-calibrate...and that is what I have done on 2 different bikes. I'll be curious to see if my friend has any issues without a new EFI map.

[grc]

Jerry,  when I had pipes put on my bike, the dealer said that I really didn't need SERT as the EFI would " self calibrate" to the fre'er breathing exhaust.  I went with the SERT and dyno tune anyway mostly to enrich the mixture and keep engine temps down.

A 2003 Harley does not have the closed loop system of the recent models, and it won't self adjust anything.  While a 2007 (2006 Dyna) and later model will self adjust in closed loop mode up to a point, the older models just follow the map that's installed.

Jerry, what other changes if any have been made?  Mufflers, air cleaner, etc.  If the only change is something like a set of V&H Dresser Duals headpipes, with the stock mufflers and air cleaner still installed, I doubt there will be enough change from the headpipes to do any harm at all.  If the air cleaner and mufflers have been changed to high flow models then he really should have it tuned.  The engine will run leaner than stock under all conditions, and stock is already very lean.  Not only does that affect driveability and power, but it creates excessive heat and can damage internal parts like pistons and valves.


Jerry

[Jerry/MD]

A 2003 Harley does not have the closed loop system of the recent models, and it won't self adjust anything.  While a 2007 (2006 Dyna) and later model will self adjust in closed loop mode up to a point, the older models just follow the map that's installed.

Jerry, what other changes if any have been made?  Mufflers, air cleaner, etc.  If the only change is something like a set of V&H Dresser Duals headpipes, with the stock mufflers and air cleaner still installed, I doubt there will be enough change from the headpipes to do any harm at all.  If the air cleaner and mufflers have been changed to high flow models then he really should have it tuned.  The engine will run leaner than stock under all conditions, and stock is already very lean.  Not only does that affect driveability and power, but it creates excessive heat and can damage internal parts like pistons and valves.


Jerry

Good points. He does not have the oxygen sensors used in the 'closed loop' systems. The bike has a high flow air cleaner and the Stage 1 download. The mufflers were changed to a high performance H-D style.... can't remember the name. The owner has been led to believe that a change to the exhaust does not require a re-mapping of the EFI. I have made recommendations based on the info I have gotten here...and my own personal experiences...but all to often relatives don't want to listen. 

[grc]

Good points. He does not have the oxygen sensors used in the 'closed loop' systems. The bike has a high flow air cleaner and the Stage 1 download. The mufflers were changed to a high performance H-D style.... can't remember the name. The owner has been led to believe that a change to the exhaust does not require a re-mapping of the EFI. I have made recommendations based on the info I have gotten here...and my own personal experiences...but all to often relatives don't want to listen. 

Considering he had the Stage 1 download to go along with the air cleaner and mufflers, he should be safe as far as being lean enough to damage the engine (in my experience the downloads are actually too rich in the top half of the rpm range).  However, those downloads didn't do a whole lot to improve low speed performance.  If he is totally satisfied with the driveability and low speed performance, I wouldn't worry about arguing with him.  The bike will no doubt run better and smoother with a good tune, but if a guy is satisfied with Thunderbird I don't know that it's worth the effort to try to convince him to spend more for a fine wine.


Jerry

[Jerry/MD]

Considering he had the Stage 1 download to go along with the air cleaner and mufflers, he should be safe as far as being lean enough to damage the engine (in my experience the downloads are actually too rich in the top half of the rpm range).  However, those downloads didn't do a whole lot to improve low speed performance.  If he is totally satisfied with the driveability and low speed performance, I wouldn't worry about arguing with him.  The bike will no doubt run better and smoother with a good tune, but if a guy is satisfied with Thunderbird I don't know that it's worth the effort to try to convince him to spend more for a fine wine.


Jerry

I wanted to make sure he wasn't risking damage to the motor. Sounds like it will be OK. Thanks for the info.