WHY DO IT:
1. Substantially more room in the Pet Carrier.
2. Allows gas system to breathe better. Whenever you remove the gas cap, you might notice a suction sound, making it tougher to remove the cap. This will solve that.
3. There's a nasty sharp screw holding on the cover of the assembly. The tip juts out, waiting to cut into your hand if you touch it in the region between the pipe and the pet carrier underbelly (everyone should at least cap or remove this screw).
4. Some people claim improved performance, it's probably just psychological though
BACKGROUND INFO, OTHER KEY REFERENCES:
Search the MV MP3 forum for "evap can" or "evaporative canister", etc, and you'll see plenty of how-to's for MP3 bikes (including one that I did when I had an MP3 500), like this . They also talk about risks (arguably almost none) and the fact that only US bikes have this and you don't need it. Voiding warranty seems a bogus claim: I told my dealer I was going to do it, he said he couldn't get involved but didn't care. There's also the not passing inspection argument: also seems bogus. California and New York don't include looking for this system. But those are just opinions. Moving on...
THE MAIN IDEA:
Take off the big plastic cover inside the pet carrier and you'll see the Evaporative Canister emissions system. There's also a diagram describing the parts. What you need to know is that the bottom hose goes to the Manifold, normally has suction and needs to be plugged.
The other (top) hose will smell of gas. This needs to vent. Add a filter here to protect it and stop the ability of an insect to crawl in, etc. It shouldn't normally ever have actual gas running through it.
Both hoses lead into the area just under and to the right of the battery enclosure. That's the area where you will do the operation.
Now then, LET'S PROCEED. You will need the following:
1. A few Torx screwdrivers (6-point star-shaped tips). The largest one is a T-40, another 1 a couple sizes lower, and a 3rd a couple sizes lower than that. The tool kit in the bike does not have the T-40. See the attached photo, I got that sweet and useful multi-purpose set for about $17 at a Walmart.
2. A sharp knife, such as in the attached.
3. A ¼" bolt about ½-3/4" long
4. Socket wrench that fits the head of the bolt.
5. An inline fuel filter (any $1-$5 model should do)
6. Optional: a couple rubber or plastic plugs (haven't measured the size yet or bought them, might repost once I do). Hose clamps.
HERE WE GO:
I figured out that you only need to remove the right-hand side panel. Not as easy as on the MP3, but I managed it. To do this, you'll need to:
1. remove the seat (when the seat is open, there are 2 obvious screws on the hinge), and
2. the luggage rack. 3 T-40 screws holds in in place. The center one is under the
3. black plate on the luggage rack, which you also need to remove. That is done by removing just 1 screw that is located underneath the rear part.
4. Underneath that, at the very back of the bike, there's a part between the brake lights that snaps off (see pic). You'll then see 1 bolt exposed that must be removed.
5. There's a few screws on the side panel that need removing. One is on the tab near the top center. One is obvious toward the front. Open the passenger peg and the top-most screw (don't drop the clip, which will probably fall out) also attaches to the side panel.
6. The panel should now wiggle out from the back, held on by the rear brake light cable.
7. There will be a tab near the middle coming from an adjacent piece that juts into a clip on the panel. Nudge that out.
8. Last step is the very front: the right side panel does a handshake with the left side. Snap this out and the panel should be completely off.
9. I also removed the battery cover, but probably didn't need to.
PERFORMING THE SURGERY:
Now the main venue is exposed (not quite as much as I'd like, but enough to do the job). Remove the plastic cover to the evap system if you haven't already. Follow the bottom hose out to the region under the battery cover. You'll see it conveniently clamped in place. Take the razor and cut straight and cleanly through this hose just after it emerges into the battery area, leaving at least an inch or 2 past the clip. Take the ¼" screw and drive it into the hose end. I couldn't quite get a socket wrench to fit in the constricted area, but I took the socket itself (which came with the hardware set, pictured) placed it over the screw head and turned it with my fingers until it naturally and completely threaded its way to being closed. I could have secured it with a hose clamp but didn't bother (it seemed perfectly tight).
Cut through the end of the other tube. Insert the fuel filter into here by twisting it in as much as you can. Ensure that the filter is in the correct direction-there should be an arrow, have that point OUT of the hose. This should be clamped too (I didn't bother). Zip tie this or tape this out of the way (I just let it hang).
Now remove the steel evap system holder: there are 3 torx bolts holding it on, their heads should be exposed on the outside of the pet carrier. With those off, slide the 2 hoses out. You might save the 2 rubber rings that were around the hoses and keep them in place so you can plug them. The whole system will pull out cleanly, in one piece (pictured).
Plug those 2 holes somehow (an auto parts store should carry something).
Plug the 3 small holes now exposed from the metal clamp.
Put all parts back on, in exact opposite order.
Finished pic1: you can see the bolt end, the filter (this is a large one), and the open holes.
Finished pic2: you can see the bolt end, the filter (this is a large one), and the open holes.