The following mod describes how to remove a catalytic converter on a 2007/08 R1. The reasons why people remove the catalytic converter is varied, ranging from wanting to free up the exhaust flow,(thereby releasing more power), to reducing underseat heat, seeing as how extra power is of no use at least to me.
DISCLAIMER:
1) The catalytic converter breaks down the exhaust gases for toxic emissions and removing it will increase pollution over the long term.Therefore, this writeup is purely in the technical sense, and carrying out this mod on the bike, is upto the owner alone.Please don't shoot the messenger!
2)This wasn't done on the pipes that are on my R1 right now, because I am worried about my warranty, and undecided about the environmental effects. I will be mounting it on and off to see the difference and then take a call on it.
3) It involves some cutting of pipes, welding etc. The work done needs to be spot on,otherwise you'll end up with an exhaust leak at the minimum, or a destroyed Y pipe at the maximum.
On with the procedure.
The catalytic converter is located in two points in the Y pipe of the R1.
We have to cut open the Y pipe just next to them and remove the catalytic converter and weld it back close.
Step 1:
Removing the end cans:
Access the clamp holding the end cans to the Y pipe, and remove the bolts securing the clamp.
After removing the end cans, your bike will look like this:
Step 1 b: Remove the o2 sensor from the Y pipe: The o2 sensor is on the right and will have to be unscrewed from the pipe.
Step 2: Removing the Y pipe from the bike:
At the bottom of the bike, you will find another clamp connecting the other end of the Y pipe to the exhaust joint at the front. Remove that as well.
Then, remove the right rearset panel very gently to avoid twisting your brake hose, and remove the heat shield covering the Y pipe.
The Y pipe will now be free of the bike. Gently remove it from inside the frame.
Now the Y pipe is free and clear.
Step 3: Cutting the Y pipe open.
Now mount the Y pipe onto a bench vise, with a cloth or rag protecting the surface of the pipe from the vise jaws. This will reduce the grip the vise has on the pipe, so keep this in mind while cutting.
Now, use a hacksaw, and start cutting the pipe.
Cut through about 3/4th the dia of the pipe, and stop. Do not cut through the pipe fully!
Now bend the pipe open in such a way that you gain access to the cat con material inside. Make sure you don't bend it at a right angle.
Step 4: Removal of the cat con.
Start removing the cat con. This is an extremely hard and rigid component. It will not come out easily, so be prepared for a tough 15-20 min. I used a hand drill to punch some holes through and then a screw driver and hammer to chip the rest off.
After removing the cat con, your Y pipe will look like this:
Now, for the second part of the cat con.
For this, I mounted the pipe onto a band saw so that I'd get a better cut. I wasn't too happy with the way I cut through the first one, so I used a band saw this time around.
Cutting done, same as last time. Cut through to only about 75% of the pipe width.
Bend open.
Same as last time.. I used a drill to make some massive holes in the cat con and remove the bulk of the stuff.
Cat con removal completed:
Step 5: Welding it close:
Now time to close the pipe up. This requires TIG welding, which is not arc welding. Since I did not have a TIG welding setup, I went to a place which did, and had it done. I tack welded using my welding apparatus, and had the rest done.
You need to make sure the welder compensates for the material lost on the pipe during the cutting. Since the Y pipe is made of steel, he will fill in the gaps with steel and weld it in. Also need to ensure good clean welds, so that you don't get exhaust gas leaks onto your ankle/leg
Pics:
Welding done.. the pipe is now cooling down:
Step 6: Installation:
Now, mount the pipe back on the bike in the exact reverse order followed in removing the bike. Preferably, use a torque wrench to tighten the nuts. All nuts have to be torqued to 10 Nm/1 m-kg on the torque wrench.
Fix back the rearset panels onto the Y pipe.
Connect the o2 sensor back into the Y pipe.
Finally, install the end cans onto the Y pipe. The fasteners here carry a torque of 17 Nm/1.7 m-kg.
Check for any loose ends, or nuts in any of the areas you've worked on. Then switch on the ignition and check for any error codes on the console. f you get an error code, make sure you screwed the o2 sensor in properly.
If all clear, switch on the bike and check for exhaust leaks. Be careful while doing this, because you will be close to extremely hot components. If you find a leak, then re-weld the cut areas on the pipe.
If all clear, then the mod is done!