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Discussion Starter #1
Hey guys,


just bought myself a new toy like two months ago, awesome bike, only soundwise it's a bit poor..
however just put on some new pipes on it and it sounds like you want it too.

My question : are there people who have experience on putting on clear sound exhaust pipes and havent installed the Fuelpack?

In the shop they only want to sell things together, hmm or they persist at least not to buy them seperately..

pricewise :
- exhaust 550€
- Fuel pack 850 € !!! (without the work)

considering it's just a chip from a few euros.. I am doubting on buying it ! :confused:

any guiys out there with some experience regarding this? :confused:

cheers
bob
 

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Just passing thru
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Hey Bob, welcome to the forum.

When you change the amount of air flowing through your motor ( exhaust and air filter) you need to adjust the fuel flow also. Years ago that meant just changing out the jets in the carb. With fuel injection you need to bias the electronic signal in order to achieve this. If you do nothing to readjust then your bike will run very lean. Thats not good because your motor will run very hot and most likely backfire or (pop) on decel. There are a few options. I went with one of the cheapest which is a Power Commander III which you can install yourself. Once you have one of these fueler/ tuners then you need to get your bike Dyno tuned and if you change your exhaust then you need to tune it again. Hope this helped.
 

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Discussion Starter #3
hey eze rider,


thx for the feedback,
I am new here and have to get used to the words you are using so can you explain to me what you meant with :
"If you do nothing to readjust then your bike will run very lean. Thats not good because your motor will run very hot and most likely backfire or (pop) on decel"

thx in advance,

btw : I am changing the exhausts tomorrow (together with the sidemount for the number plate) but the fuel packs are not in , problems with deliveries... so I guess I will run lean in the beginning ;)
but if i understand what you mean here above then I can check if my bike has the same behavior, if yes then I go for the fuelpack as soon as it is available again...
 

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When the bike comes out of the factory the air to fuel percentage is determined by the engineers and set for only that one setting. If you change your exhaust and/or your air filter then you are changing the air to fuel percentage. You are allowing more air to flow through your motor yet the amount of fuel remains the same making for a poor mixture and your bike will run lean (too much air and not enough fuel) this makes your motor run too hot and it will perform poorly. The advice to install the tuner is good advice.
 

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BatRod
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The '08 Nightster has O2 sensors, so it can compensate somewhat for the new exhaust, I believe. It won't, however, likely be legal anywhere in Europe.....
 

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Discussion Starter #7
hey,


nor is the sidemount legal, exhausts similar, but I keep the original ones, in case they catch me we just change it back for an hour or so ;-)

I did understood the lean theory, had similar problems before in my youth with a 49cc where you could speed him up by making your bike leaner just by not giving it enough fuel, closing of the fuel filter then open it again close etc.., however in summer time your engine could fail because of heath, hmm workaround piss on the ciliinder ;-) and off you go again

I was more referring to the backfire or pop on decel, that's why I didn't understood ;-)

thx
cheers
bob
 

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Hey Bob,

Decel meaning when you release your throttle when slowing down. If you were running a lean setting on your bike in the past you must have noticed the "popping" noise or even a couple of big bangs from the exhaust while slowing down?

Even if your 08 with o2 sensor could readjust enough it would still be readjusting to the factory lean and green settings. Go for the performance!
 

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Discussion Starter #9
hey thx for the information,

what is causing the big bang or popping technically? I understand because it's related to the leanness of the engine, but what happens in the engine when it backfires?

br,
bob
 

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In my experience, every 4 cycle gasoline engine, whether in a car or bike, will "pop" on decel. Most times you can't hear it because the mufflers, uh, muffle it. Popping is completely normal and unavoidable. As far as fuel injection goes, It is designed solely to be able to correct for rich and lean conditions, something carburetors can't do. So, as long as the change to exhaust/intake is not too extreme, the ECM will compensate for the lean condition and bring it back to 14.7:1. It does this by monitoring the intake air flow, and the exhaust oxygen content, making a correction, and rechecking. It does this until the mixture is correct, and remembers the fuel injector pulse width. If it gets to the point where the ECM can no longer correct for rich or lean conditions, the check engine light will come on. Sorry for the long reply, but I wanted to try and explain as clearly as possible.
 
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