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EXUP Removal help please

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Does removing the Exup system do anything for the bike? I have read several posts of people doing it. If it helps, can someone walk me through it.

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If your planning on adding aftermarket exhaust, intake, fuel tuner then yes it will help, otherwise I would suggest leaving it stock.

if you are going to mod then get all three components at the same time, or at least the pipe and programmer, then do the free mods to the airbox.

the exup removal can get in depth if you want to substitute the servo, which I have been making a sub for other people on this site.

elaborate on your plans and we will be happy to walk you through it.

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Has anybody dynoed it with and without the EXUP? Unless my memory is betraying me, Yamaha originally put the EXUP system on their YZFs to boost midrange - something our WRs could sure use more of, not less. I don't want to save two pounds by removing it and lose 1-2 horses at lower rpm. I'd appreciate hearing dyno results or seat-of-the-pants impressions from people who have done this mod. I'm of the mindset that Yamaha put it there for more than a marketing exercise!

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Has anybody dynoed it with and without the EXUP?

Just posted my results today, I have done lots of mods, but mainly

Powercore 4

K&N air filter

pulled the top off the air box (flapper and ais all gone)

Servo Sub

Power Programmer

31hp

and feels stronger, lighter, faster than the my last bike 02 WR250F

Thats a great point. If it doesnt choke the engine off, or cause problems with a slip on, then I may leave it alone.

And yes the exup will have to be removed for the Powercore to go on......

Unless my memory is betraying me, Yamaha originally put the EXUP system on their YZFs to boost midrange

Also yes it was desinged to simulate a shorter or longer header by closing off or opening up and leaning out or richening the combustion chamber of the bike with backpressure its purpose is well engineered and should only be removed if your using more air in and out and adding fuel to the mix......

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Also yes it was desinged to simulate a shorter or longer header by closing off or opening up and leaning out or richening the combustion chamber of the bike with backpressure its purpose is well engineered and should only be removed if your using more air in and out and adding fuel to the mix......

Steveakus, what will happen if I install a fuel tuner(FMF or PC III) and K&N air filter without doing this mod? Will it just be an underperformance issue for the engine or will there be some sort of damage in the long run? The pipe is going to have to wait until next spring I think.

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Steve,

Can I just put the powercore on without removing the Exup or will it damage anything. Does anyone have the steps to remove Exup? I am pretty new to bike mechanics and this machine is pretty complicated.

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Steve,

Can I just put the powercore on without removing the Exup or will it damage anything. Does anyone have the steps to remove Exup? I am pretty new to bike mechanics and this machine is pretty complicated.

No you can not. The exup is part of the stock exhaust that will

be removed when you go to install the new powercore.

For now, just remove the two cables connected to the exup

valve. Pretty self explanatory when you look at the cables, but

basically they are like small throttle/idle cables. Dont worry

about the servo motor right now. You can just leave

it installed with the stock harness plugged in, that way you

dont get a check engine light.

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So just remove the cables and leave the valve mechanism? I can do that. I still should leave the boxes from each of the bike? The one on the left side and the one on the exhaust will go with the old muffler right?

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So just remove the cables and leave the valve mechanism? I can do that. I still should leave the boxes from each of the bike? The one on the left side and the one on the exhaust will go with the old muffler right?

No.....you will not leave the valve mechanism.

Lets clarify what we are talking about. The "black box" on the

left side, beneath the batter....that is the servo motor. It

is connected to the bike through a wiring harness that feeds

info back to the ECU (electronic control unit = computer).

This servo, you can just leave in place with the wiring harness

plugged in. (if you wish to remove it you can get with Steve,

and he can make you a servo-sub......The advantage to this

would primarily be weight loss, so its not really a "have to").

From the servo is two cables that are similar to throttle/idle

cables. Just remove the outer cover of the servo, disconnect

the cables, and replace the cover. The opposite end of the

cables connect to the exup valve on the right side of the

bike just past the header portion of the exhaust. Remove

your right side plate (white plastic cover) and then remove

the small circular shaped cap that covers where the cables

connect to the exhaust. Remove the cables. Now when you

remove the exhaust, you will remove the exup valve (which

is part of the stock exhaust) and reinstall the new powercore.

The only item that now remains of the exup system, is the

servo motor beneath the batter.

Hope this helps.:)

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AWESOME! I really appreciate your help! That is what I was looking for. This bike means so much to me and I am afraid of doing some damage by negligence so your walkthru is a big help. I cant wait for my powercore to arrivce now!

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Hi,

Some of my comments may seem a little different than the excellent comments you have gotten so far. Everyone has a point of view, here's another to take into account:D

1. Installing any aftermarket exhaust makes your bike illegal to ride on the street. You are violating Federal regulations by removing the stock exhaust. There are no street-legal aftermarket exhausts on the market as of now. There are two reasons why: a) no aftermarket exhaust meet the loudness requirements, and :D you are removing a catalytic converter.

2. The EXUP system does two main things: a) boost low and mid rpm by simulating a longer pipe, and :worthy: controlling exhaust noise at low rpms. By removing it, you lose those functions.

3. The stock ECM (fuel computer) cannot adjust for the change in intake or exhaust flow. If you open it up, you will be running leaner. How much leaner? Will you damage your bike? No way to know, and no one has been running them long enough to say anything except it does not cause immediate damage.

4. It has often been said here, and I agree, that it is best to install an aftermarket exhaust and a fuel computer (Power Commander III, or other) at the same time. Or install the PCIII first. That way you have some control over the fuel, and can enrich the mixture to counteract the leaning out caused by a freer-flowing exhaust. The people that have installed the PCIII first report good things with that mod alone. If I had to spend $300, I would spend it there before on any slip-on. Wait, I did spend $300 on the PCIII.

Well, enough (or maybe more than enough) for a start. :)

Cheers!

/dh

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Very good point. I definitely will consider getting the fuel programmer and doing them together then. How much louder will this thing be? It purrs now, I wouldnt mind a bit of bark but dont want a harley either.

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Zadok,

You got any cure for the throttle lurch and jerk in 1st and 2nd? Man this thing really likes to be all or none.

Yes, refer to Hermits post just before your question. A fuel

tuner will be a great help, and I actually do agree with him

about doing to the tuner before, or at the same time of the

exhaust change. The fuel tuner (whether FMF or PCIII) will

help with making the AFR (air fuel ratios) more consistent

throughout. I personally (as well as Steve) run the FMF,

but I have no issues with the PCIII either. The FMF is just

a bit more simplified and less complex for those that might

be interested. I have a fair amount of EFI tuning experience

and have, and do, run much more complicated systems

than the FMF, but I like the simplicity of that system for

this particular bike.

As far as the "not being legal" part of Hermits post. He is

right, but I live in Oklahoma, and these good ol boys around

here are not the least bit worried about an aftermarket

exhaust on my new bike. At least not right now theyre not.:)

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So 96db isnt like these harleys running around is it? Those things will leave your ears ringing.

It's higher pitched, obviously, than the "Harley" sound. But it's loud.

It depends on what you want, and how long your rides will be, and where. I really enjoy not wearing earplugs when I ride. At 80 db i can ride as long as the gas holds out and not have my ears ringing when i stop.

And I guess I am an overly courteous guy. I don't want to impose my pleasures on others, and a lot of folks don't appreciate loud motorcycles of any size. If you ride mostly offroad, then the balance may go the other way, since offroad 96 db is probably lower than average.

I find that making these choices on how to make the bike "yours" is a great way to think about what you want, and then make it work. I hope you listen to all of us very helpful folks here, but in the end make up your own mind about what matters to you. It's your bike, your fun, your responsibility, your choice.

Happy to keep throwing stuff out/dh

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A thousand bucks for a paltry 6+/- HP and a loud exhaust to boot? This is one of the least effective hopup schemes I've ever seen for a motorcycle. To each his own I guess.:)

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A thousand bucks for a paltry 6+/- HP and a loud exhaust to boot? This is one of the least effective hopup schemes I've ever seen for a motorcycle. To each his own I guess.:)

Where did you get 1k dollars? The FMF exhaust can be

had for about 250, and the FMf power programmer runs

about 210, the air box mod is free. So that looks an

awful lot like 460 bucks plus shipping.

In addition to that......the stock exhaust looks like

dog sheet IMO. So I guess its a looks preference too.

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