Back to stock

I picked up my WR250R just a week ago. It's a low-mile bike with two previous owners. The last owner fitted (1) Powercore pipe, (2) Power Bomb header, (3) FMF programmer, and (4) EXUP emulator.

I generally prefer to keep my bikes stock, and thankfully the previous owner kept the original parts. I rode for a week with the FMF parts but decided to return to stock, mostly because I get self-conscious about the noise. (Surprisingly, the stock exhaust isn't that quiet.) Other concerns: Fuel mileage, long-term reliability questions, and twice already the programmer cut fuel at freeway speeds, even after following recommendations for changing one setting (fifth?) to 6.0 or higher.

I was anxious about returning to stock because I don't have much experience with this stuff, my mechanical fiddling of motorcycles is generally limited to chain adjustments and oil changes, and because I wasn't sure if the previous owner kept all of the parts. There's not a lot of documentation for reversing an exhaust mod, so it's hard to know that I've got everything until potentially too late -- I was afraid of taking the bike apart and half back together before realizing I need to order some part from Yamaha. Thankfully, the only thing missing was a bolt, which I was able to replace at a local hardware store.

Anyway, because there's not so much documentation for this un-mod, I thought it'd be useful to write out the steps I took, and a rough list of required parts.

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Objectives:

• Remove FMF programmer
  
• Remove FMF header + pipe
  
• Reinstall stock header + pipe
  
• Reinstall EXUP servo
  
• Avoid error codes :)
  

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List of parts required:

• Stock header
  
• Stock heat shield (with 2x bolts)
  
• Stock exhaust pipe (with 2x M10 1.25 bolts -- the FMF pipe uses a smaller thread for one of them)
  
• Stock pipe cover (with 3x bolts)
  
• EXUP servo (electric motor)
  
• 2x cables with L-shaped sleeves (connects servo to EXUP valve on pipe)
  

That's it. I think. I wasn't writing this down while doing it. I used the same bolts for the header pipe as were used to mount the FMF header. Re-used one of the FMF pipe bolts (other was too small for stock). The bolts for mounting the EXUP servo were still attached to the bike, being used to hold on a small metal bracket that the rubber strap holding in the battery clips onto.

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Process:

Remove stuff from the bike in order to access the parts we're looking to change. Some good photos in this PDF from FMF. Stuff removed includes:

• Remove plastic panels under the seat (1x bolt each)
  
• Remove the seat (2x bolts under the rear wheel well)
  
• Remove the radiator shrouds (2x bolts each)
  
• Remove the bolts (3x) holding the gas tank in place (leave the gas tank on the bike)
  
• Remove the rear, small plastic mudguard separate the rear wheel and the bike's electrics (2x bolts)
  

With these bits removed, you can access everything you need to access. Now, removing the FMF parts...

Remove pipe + header:

• Unbolt / remove the heat shield (some bikes don't have this)
  
• Unbolt the pipe (2x bolts) and pull it backward and off the bike
  
• Unbolt the header (2x bolts) and pull it forward and off the bike
  

The programmer is simple, but a bit tricker. Mine was mounted on the battery.

Remove the programmer:

• Free the programmer from any mounting (zip ties, etc.)
  
• Release the ground wire from the battery terminal (mine was under the negative)
  
• Follow the main wiring from the programmer to under the gas tank (lift the gas tank enough to reach under)
  
• The programmer's wiring splits into two:
  
  
  
  • One connects to a wire+connector coming off the bottom of the gas tank
    
  • A second connects to a connector on the bike, directly under the gas tank
    
  
  
  
• Disconnect both FMF connectors
  
• Connect the two connectors that are left on the bike to each other
  
• Completely remove the programmer
  

And finally, the EXUP emulator, which looks like a small black plastic cap covering one of the connectors. It's on the left side of the bike, rear of the battery. The connector comes off the battery and just plugs into the EXUP emulator, so it looks like it does nothing (pretty much what you want it to do).

At this point, I was starting to feel pretty good. Everything was pretty simple and happening as expected.

Now, the re-assembly with the stock exhaust parts.

First, mount the stock header + pipe:

• Loosely attach the header, leaving the bolts (2x) loose enough to allow play
  
• Loosely attach the pipe, leaving the bolts (2x) loose enough to allow play
  
• Tighten the bolts on the pipe
  
• Tighten the clamp bolt connecting the pipe to the header
  
• Tighten the bolts on the header
  

That was pretty easy. The EXUP servo + cabling proved to be the most difficult part of the reassembly, partially because of the tight spaces and the particular arrangement of parts, but also because there are very few photos on the web showing where the hell the EXUP servo is supposed to go. The EXUP valve is on the exhaust (right side of the bike), but the servo fits just underneath the battery (left side of the bike).

Mount the EXUP servo:

• Remove the plastic cap on the EXUP servo (it covers the rotating motor that connects to the cables)
  
• Remove the cables
  
• Unscrew the small metal bracket that the battery is strapped to (under the battery)
  
• Fit the EXUP servo under the battery, with the un-capped motor facing outward
  
• Connect the servo to the battery via the connector we earlier released from the EXUP emulator cap
  
• Re-screw the small metal bracket on top of the holes for the EXUP servo to mount both the bracket and the servo motor
  

That's the easy part. The hard part is the cabling.

The EXUP cabling runs from the left side of the bike (servo) to the right side of the bike (valve). The cables start at the servo motor with an L-shaped bend in them, first pointing toward the rear of the bike and then immediately turning toward the right side (toward the exhaust). There is a small crevice behind the plastic that separates the wheel well from the bike's electrics, and in that crevice are two small, round notches for the EXUP cables. (When I earlier suggested removing the small plastic mudguard, this is why -- makes it easier to route the cables.)

• Route the cables through the bike
  
• Connect the L-shaped ends with the EXUP servo motor
  

At this point, it's worth noting that the two EXUP cables are not identical. One has a black anodization at the valve end, and one has a silver anodization. Under the servo motor's cap are labels "1" and "2" which indicate which cable is which. The cable with the black end connects to the side marked "1" (note: the black end is still for the valve, not the servo). The silver-anodized cable connects to the side marked "2."

Now, to the other side of the bike.

• Unscrew and remove the cap on the EXUP valve (top of the exhaust pipe, just fore of the right side passenger peg)
  
• Pull the (very stiff) cables toward the EXUP valve
  
• Loosen the outermost nuts on the end of either cable (to more easily slip on the mounting clips)
  
• Connect the black-anodized cable to the outside position
  
• Connect the silver-anodized cable to the inside position
  

Each cable has two small nuts, which should straddle the mounting clips. These hold the cables in place, but importantly they also adjust the slack in the cables. The service manual specifies that there should be no slack in the cables. BUT, before you adjust the cables you need to reset the position of the servo motor. As you can imagine, the position of the servo motor will affect the amount of slack at the valve end of the cables.

To reset the position of the servo motor, the service manual specifies to activate the bike's diagnostics mode.

• Turn the bike off, and leave the kill switch in the "kill" position
  
• Press and hold RESET + SELECT 1 buttons
  
• While holding those buttons, turn the key to ON
  
• Keep RESET + SELECT 1 held for about eight seconds, until the dash reads "DIAG"
  
• Release the buttons, and the press and hold RESET + SELECT 1 (again) for about two seconds
  
• The dash will then switch into diagnostics mode
  

Here's a good video that shows the process of getting to diagnostics mode. From diagnostics mode...

• Press the SELECT 1 button to navigate between diagnostics modes -- the top line of the dash indicates the mode you're in (e.g. d1:01, d1:02, etc.)
  
• Navigate to d1:53, which is the EXUP servo diagnostics
  
• Flip the kill switch (uh, to the un-kill position)
  
• The bike will activate the servo and test it out, leaving the servo in the ideal position for adjusting the cables
  

You can turn the bike off now and adjust those EXUP cables at the valve end. Twist the large anodized metal section rear of the mounting clip to pull out the slack in the cables. When both cables are at roughly even amounts of slack (and as little slack as possible), tighten the outside nuts against the mounting clip.

Whoa, we're basically done now. At this point, you should run the bike to make sure everything's functioning, no check engine lights indicating an error, etc., before putting it back together. Would hate to find out too late that something's not right.

When it is time to put the bike back together...

• Put the cover on the EXUP valve (2x bolts)
  
• Put the cover on the EXUP servo (2x screws)
  
• Re-attach the small plastic mudguard behind the rear wheel (2x bolts)
  
• Re-mount the gas tank (3x bolts)
  
• Re-attach the plastics
  
• Re-attach the seat (2x bolts)
  

Now you're back to stock.

So, how do you like the stock bike?

Basically did this to my bike except I did not re-install the AIS system and I had an extra stock muffler that I took apart to remove the cat from it.

The EXUP cable routing to the valve was the hardest part of the whole process. Basically had the same issues that you mentioned in your write up.

Jens Eskildsen wrote:

So, how do you like the stock bike?

Too early to say, I've only done a quick test ride to verify the bike still worked :) My initial thoughts: Stock pipe still sounds very good, not as quiet as my Ninja 250 was with stock pipe, still a bit of fruity fun. Maybe a bit less low-end grunt, but at the high end of the RPM range it feels less gasping for air (probably could've done more mods to address this with the FMF parts). I'll give it a week like this, and if I'm 100% happy I'll sell off the FMF parts, which have fewer than 500 miles on them.

rsteiger wrote:

Basically did this to my bike except I did not re-install the AIS system and I had an extra stock muffler that I took apart to remove the cat from it.

My bike still had the AIS attached, thankfully.

If you decide to sell them I may be interested

Good thread. I'm in the process of doing this as Australian laws require a stock bike for riders on a restricted licence. After a year I can get my full license and modify how I see fit. While my 250X came with a Powercore4, Powerbomb header and PCV, the Powercore is too loud for my tastes so I'm removing it all and keeping the PCV in the cupboard for a year. Any tips on getting the gasket in between the header and muffler fitted?

Thanks for the detailed post. I have an FMF Q4 only - without the header, and I want to go back to stock pipe to keep things quiet. I believe the EXUP and the AIS have been addressed by the PO. Bike also has the programmer on it.

Question - If i installed the stock pipe, do I have to mess around with the EXUP and AIS? My understanding was that it is a straight bolt-on and re-programming? Am I understanding this correctly?

You don't have to hook the exup back up at all if you don't want to, it just makes the bike quieter at certain speeds for noise testing and the ais just adds air to lower the % of emissions the bike puts out, more air coming out of the exhaust equals a lower % of emissions lol.



MRSallee Are you claiming the bike makes less low end grunt with the stock pipe than it did with the fmf?

I just want this to be clear as I've seen it posted that the stock pipe has better low end and also that a fmf pipe has better low end.

I found adding a fmf Q4, opening the airbox up and running a fmf programmer added low end grunt to my bike along with more top end HP, theres a few guys on this site who claim the stock pipe has better low end grunt tho.
The first thing I noticed after doing the mods was better lugging power and it was harder to stall, the extra top end hp is just the icing on the cake with a pipe.