When I first bought my Yamaha R6 I knew that it had Yamaha’s revolutionary EXUP Valve system installed in the exhaust. One of the first things I did when converting it to a race bike was to eliminate the EXUP so that a full-system, higher performance exhaust could be installed.
According to Yamaha…
A variable valve system that eliminates “valleys” in the torque development curve in 4-stroke engines. With continual improvement since the first adoption on the ’87 model FZR400R, the latest version is used on the YZF-R1.
Luckily for me the instructions were posted on the R6 Forums with pictures to boot!
Here are the procedures:
Brief Description: This guide will cover how to remove the EXUP cables from the EXUP butterfly valve on a STOCK 07′ exhaust, and how to create a bypass for the EXUP servo in the EXUP control box to eliminate the check engine light and diagnostic codes #17 & #18 from appearing. The entire process from start to finish will take approximately 30 minutes to 1 hour. (Note: This same process can be used with aftermarket exhausts and slip-on’s to eliminate the same check engine light and error codes). This is the $2 EXUP fix DIY rather than paying $70 for the Graves EXUP eliminator, both work and both are essentially the same thing.
What You’ll Need
- 8 mm or 10 mm adjustable wrench
- Phillips Head Screwdriver
- Wire Cutters
- Allen Wrench (s)
- Adjustable Crescent Wrench
- 4.7 kOhm Resistor 1/2 Watt
- 470uF 35v Capacitor
- Soldering Iron (w/ Solder & Flux)
- Electrical Tape
Remove the EXUP Butterfly Valve Cover from the Exhaust by removing bolts #1, #2, and #3. This will give you access to the EXUP cables so they can be removed (as shown below).
Above is a close up of the nuts holding the EXUP cables in place to the butterfly valve. Remove nuts #1 & #2 first so that you can remove EXUP cable #2, and then remove nuts #3 & #4 so that you can remove EXUP cable #1.
Before the cables can be completely removed, you must also remove a small bracket holding the cables in place. To do this remove screw #1 with a crescent wrench (Yes this picture is without the EXUP butterfly valve cover removed, I forgot to take the picture during the process and did so after I completed the bypass)
Now that the EXUP cables have been removed from the bike, you must remove the EXUP control box (Housing the EXUP servo and motor).
To do this remove bolts #1 & #2 using an 8mm crescent wrench (or 10mm for 2010+ models). After these bolts have been removed, along with the previous process for the EXUP cables the whole assembly (EXUP Control Box and Cables) should be easily removed by pulling out the right side of the bike. You will have to remove the EXUP control wires from the EXUP servo connection before doing this (Picture shown below)
It should look something like this:
After completely removing the EXUP Control Box and EXUP Cables from the bike you are ready to rewire the servo using the 4.7 kOhm 1/2 Capacitor and 470uF 35v Capacitor. Set up your soldering iron so it can heat up and complete the following directions.
First remove the rubber cover around the EXUP Control Box
Once the rubber cover has been removed it should look like the above picture. Next remove the EXUP cables from the EXUP control box. Now we must remove bolt #7. To do this use an adjustable wrench at #8 to hold the bolt in place, and use an Allen wrench to remove bolt #7. After this has been completed use a Phillips head screwdriver to remove screws #1, #2, #3, #4, #5, and #6. After removing the above bolt and screws the top cover of the EXUP control box should be easily removable.
After removing the cover from the EXUP control box the internal components should look something like this. Remove the plug, motor, gears and pull all of the components out of the housing.
Next, cut all of the wires as shown above. Don’t worry too much about the green and red wires as they will not be used for anything, but do make sure you have enough orange, black and white wire to strip the ends of them. You can discard the motor and gear control.
Now we will rewire the servo to trick the ECU into thinking the EXUP is still connected, but effectively removing the check engine light and #17 & #18 warning codes. To do this strip the ends of the black, white and orange wires. After this has been done solder the black and white wires together. Also, I recommend taping off the green and red wires with electrical tape to prevent any arcing.
Now solder the 4.7 kOhm 1/2 watt resistor to the black and white wires as shown. Be sure to connect the correct end (shown by a gold strip on the side of the resistor that is connected to the black/white wires). After doing this, solder the 470uF 35v capacitor to the orange wire as shown (The black strip on the capacitor with the negative sign, denotes “negative” – be sure to solder this side to the orange wire). And finally solder the positive side of the capacitor to the correct end of the resistor (shown by a yellow strip on the side of the resistor that is connected to the capacitor). Once you are done it should look like the above picture.
Once the bypass has been made I recommend taping off all bare wire with electrical tape to prevent any arching. Not sure if it matters if you cover the resistor or capacitor, but just in case I did not.
After completing the bypass install it back into the housing, making sure to properly insert the EXUP connector back into the plug housing. Also, don’t forget to re install the white plug that holds the EXUP connector in place. Once this has been completed, refer to the above steps to re install the EXUP control box cover and rubber cover. Plug the EXUP wire on the back of the bike back into the EXUP Control box (EXUP Servo Connections) and reinstall it back on the bike. Also, if you havn’t already remember to re install the EXUP butterfly valve cover that was taken off at the beginning of step one.
I followed the above procedures exactly and have had no problems at all. I take no credit for this as it all belongs to the R6 Forum. Thanks to those guys for such an awesome website and passing so much information.