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It seems about a 50 / 50 mix as to whether you need to remap when putting on a slip on muffler and keeping the stock air filter. Does anyone really know if it is necessary to remap?
I'm think about S&S Grand National slip on.

If I did change the air filter is it necessary to remap?

I'm an old coot (72) and this remapping stuff is quite confusing to me and I'm sure I DON'T know how to do it. I have owned numerous bikes but never remapped any of them for any reason.

Who can straighten me out on this ? And THANKS.
Rich
 

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Slip on only...no need to flash. I ran my little 500 with a slip on and no problems. I did the K&N naked intake and FP3 and flashed it then. Good Luck!
 

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Remapping is the equivalent of changing carburetor jets to correct the fuel/air mixture. You don't have to do it until you do something to upset the mixture, like changing the intake. Now that more air is available you can make more fuel available by remapping. That's assuming there is a free flowing exhaust to vent the increased combustion gasses.

I've read that you can change the intake or the muffler without remapping, but once you change both of those you must remap or have poor performance and popping on deceleration.

All of that being said, the stock bike can benefit from an EFI tune just because the engine comes from the factory tuned towards the lean side.
 

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I changed the exhaust on mine to a Firebrand GP and put a Screamin' Eagle air filter on. I ran a couple of weeks without a remap and it ran fine although the tickover was a little haphazard. I brought an FP3 and did an 'autotune' as there were no maps available for my set up that I fancied. After the remap the tickover was smoother and the bike was happier to quickly 'pick up' better at all engine speeds. Had I not done the retune I possibly would have never known that there could be an improvement. Having said that, most people seem to agree that the ser up at factoey is very 'lean' due to fuel emissions? and therefore all bikes would likely run better after a retune.
I am no 'tech wizard' but the FP3 was simple to set up and use although it is a little pricey. If you are happy with your present exhaust and air filter and are a little aprehensive about altering the ECU yourself with a tuner then you could take it along to a dealer and they could perform the retune for you, I however prefer to do things myself and I also like the additional features that the FP3 has to offer ;)
 

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I vowed not to change everything at once but instead change the exhaust only and see how it ran. Then change the intake and see how it ran. Then finally do the tuner. That didn't happen. Everything got swapped out at once just ahead of the riding season. Thee was no stock map for my setup on the FP3. Instead of calling customer service I randomly picked a setup and had an awful decel pop. About an hour of autotuned cleared it right up, but another couple of autotuned sessions refined that.

The V&H FP3 may be expensive, but it's the cheapest tuner available. That was the deal with my stage one upgrades, I pretty much went with the cheapest components I could find. Maybe down the road I'll go with a full intake replacement instead of just the K&N free flowing air filter. Maybe I'll change from the short little TAB slip on muffler to a V&H. Maybe not.
 

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It seems about a 50 / 50 mix as to whether you need to remap when putting on a slip on muffler and keeping the stock air filter. Does anyone really know if it is necessary to remap?
I'm think about S&S Grand National slip on.

If I did change the air filter is it necessary to remap?

I'm an old coot (72) and this remapping stuff is quite confusing to me and I'm sure I DON'T know how to do it. I have owned numerous bikes but never remapped any of them for any reason.

Who can straighten me out on this ? And THANKS.
Rich
If the slip on is free flow, then you need to provide a richer air fuel mixture otherwise your bike will run lean and that is harmful for the engine. A remap here will help by providing the rich air fuel mixture and thus safeguard your engine. I hope this helps.
 

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If the slip on is free flow, then you need to provide a richer air fuel mixture otherwise your bike will run lean and that is harmful for the engine.
Changing the muffler isn't going to lean the mix. You would need to change the air intake to do that, at which point you would need to tune. Think about it. The muffler has nothing to do with creating more flow on the intake side of the equation, it just makes it easier to pass the combustion gasses out of the engine.
 

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Changing the muffler isn't going to lean the mix. You would need to change the air intake to do that, at which point you would need to tune. Think about it. The muffler has nothing to do with creating more flow on the intake side of the equation, it just makes it easier to pass the combustion gasses out of the engine.
In theory you are right. A free flow intake will definitely make the mixture leaner with more air flowing in and hence the need for retuning the engine. However, I will try and explain the real effect of a free flow slip on and why we say that a richer air fuel mixture is needed.
The factory fitted exhausts are designed to have back pressure from the exhaust, which is gone the moment the free flow slip on is fitted. The effect of the back pressure is that, the complete exhaust gases are not expelled out and the small quantum of the exhaust gases remain in the combustion chamber which act to cool the chamber and retard the combustion in the chamber as a result of which the new air fuel mixture acts as lubricant. Now, when the back pressure is totally removed, the combustion is more efficient resulting in more heat being produced and resulting in less lubricating effect being produced. Therefore, to overcome this effect, a richer mixture is needed which helps in reducing the combustion chamber temperature and for better lubrication, thereby ensuring that the engine does not suffer damage.
I hope I have been able to explain. Having said that, the ideal combination is installing both, the free flow air filter and the slip on and then remapping/tuning the bike for best results.
 
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