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Just purchased my Two Brothers exhaust on ebay today! $245 + $22 shipping. BTW Scuzz, don't worry about the vid anymore, I saw this deal and couldn't pass it up. My next purchase is a PCIII. I'm still a college student working part-time, so I don't have the funds quite yet to purchase the PCIII. Should I leave the exhaust off until I get the PCIII? I don't want the quad to run too lean or rich and be bad for it.
 

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If you want to use a HMF Optimizer I will give you a good deal on mine.
 

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I also have the two brothers dobeck, if you want that since it's matched to the muffler.

I wouldn't run the muffler without it.
EFI doesn't tend to run lean when changes like this are made like carb atv's do.

EFI measures airflow and gives fuel to match, Making simple changes like this will not adversely effect it. On carb atv's pressure changes from free flowing exhaust and intakes will cause a lower suction across the jet and make lean conditions. Works the other way also, If your intake is really dirty it makes a higher suction across the jet giving you a rich condition.
 

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Discussion Starter · #6 ·
EFI doesn't tend to run lean when changes like this are made like carb atv's do.

EFI measures airflow and gives fuel to match, Making simple changes like this will not adversely effect it. On carb atv's pressure changes from free flowing exhaust and intakes will cause a lower suction across the jet and make lean conditions. Works the other way also, If your intake is really dirty it makes a higher suction across the jet giving you a rich condition.
So, it wouldn't be hard on the quad to run without the EFI controller? I'm definately going to get one, but if I can run it fine without the controller for awhile I'll go ahead and install it right when I get it.
 

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I put a pipe on my Rincon 680 efi without the controller and after a jaunt down the trail and back my plug was snow white. Got the controller and the plug was tan.
 

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EFI doesn't tend to run lean when changes like this are made like carb atv's do.

EFI measures airflow and gives fuel to match, Making simple changes like this will not adversely effect it. On carb atv's pressure changes from free flowing exhaust and intakes will cause a lower suction across the jet and make lean conditions. Works the other way also, If your intake is really dirty it makes a higher suction across the jet giving you a rich condition.
I couldn't disagree more......IMO swapping to an aftermarket slip-on without a fuel controller is just asking for problems. KA-BooooM !

The 700XX uses a rather simple form of Fuel Injection known as "Open Loop". This means that the fuel injected in to the engine is a set amount and is only altered when there is a measured change in atmostpheric conditions.......eg: high altitude. It does not automaticlly adjust when changes are made to the engine like exhaust systems and free flowing filters.

If you change intake or exhaust conditions (more free flowing) then you will lean out the air/fuel mixture.......if its easier to get air in to the engine then it will need more fuel to match. The computer will not adjust this automaticly.

Seeing that the stock 700XX silencer is very restricted, an aftermarket slip-on will make a large difference to the "flow" of the entire engine and you will need an aftermarket fuel controller to bring the engine back to a safe air/fuel mixture......a byproduct of this safe condition is more power.

Linc
 

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I couldn't disagree more......IMO swapping to an aftermarket slip-on without a fuel controller is just asking for problems. KA-BooooM !

The 700XX uses a rather simple form of Fuel Injection known as "Open Loop". This means that the fuel injected in to the engine is a set amount and is only altered when there is a measured change in atmostpheric conditions.......eg: high altitude. It does not automaticlly adjust when changes are made to the engine like exhaust systems and free flowing filters.

If you change intake or exhaust conditions (more free flowing) then you will lean out the air/fuel mixture.......if its easier to get air in to the engine then it will need more fuel to match. The computer will not adjust this automaticly.

Seeing that the stock 700XX silencer is very restricted, an aftermarket slip-on will make a large difference to the "flow" of the entire engine and you will need an aftermarket fuel controller to bring the engine back to a safe air/fuel mixture......a byproduct of this safe condition is more power.

Linc

Nope... The open loop system still monitors varying conditions and adjust to its ability. It reads all of the following:

Intake charge temp
Atmospheric pressure
RPM
Coolant Temp
Throttle Position
TB Suction Pressure

We all know it doesn't have an O2 sensor that would allow it to cover more variables but It does however have multiple "maps" programmed into it to pick from by reading the listed sensors. If it didn't you would have the same cold weather starting problems of a carb and so on. The ECU does in fact read the sensors and make adjustments as necessary. It does have limits but a filter and slip-on are within its ability.
 

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If you added a slip-on and filter and it began to run lean the engine would get hotter, The ecu would see the higher engine temps and add more fuel to cool it down. There is a bit more to it but thats just a basic instance of how it works
 

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If you added a slip-on and filter and it began to run lean the engine would get hotter, The ecu would see the higher engine temps and add more fuel to cool it down. There is a bit more to it but thats just a basic instance of how it works
We'll just have to agree to disagree. IMO all you have pointed out is that the ECU will adjust to varing atmostpheric conditions.
 

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Tried this tonight. You can't run the pipe without a controller. My buddies plug is pure white. I'm below sea level so not sure if that has anything to do with it also.
 

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Just trying to tell ya what I know lol. Here is a little something on Honda's PCM-FI system. It doesn't give a black & white answer but its a good read.

http://world.honda.com/motorcycle-technology/pgm-fi/p6.html
I really dont care what Honda propaganda you have been reading. The most it will do is adjust for some changes in atmospheric conditions.

Dont want to sound like a prick but I think this does need to be debated as going round saying you can add a slip-on without a controller is just going to result in someone comming after your head.

Linc
 

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I've added full header back exhausts to two different motorcycles, a gixxer 750 and a Boulevard M50. Both bikes ran absolutely perfect with the exhaust on them. I'm not sure how different Honda is but from what I hear you have to use a programmer once you add a after market air filter. At that point the motor can't adjust. I'm not going to buy a slip on just yet but I'd be comfortable using it without a programmer.
 

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I have run slip-ons on my sport bike without a programmer and they both ran incredible for years. Both were Hondas, a CBR900RR (carb) and a CBR954RR (efi). The big debate should be: Why would you want to run an exhaust without a controller. Knowing what I know now I would have run a controller on the 954 and rejetted the 900. At the time the controller programming was a little intimidating to me. The controller is designed to compliment and compensate for the increase air flow. I have both on my 700XX and love it. I know it's hard to come up with an extra $300 for the controller (convincing my wife wasn't easy), but you won't be disappointed...except maybe with the extra fuel you'll be burning.
 
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