I think it's usually referred to as a 'chin fairing' or 'chin guard'. And no, it won't fit on a 650. As the chin fairing provides no real protection, I'd recommend you buy and install a skid plate- do a search on here for 'bash plate' and 'skid plate'.
I made my own...
And this is how I got there. It isn't hard to see where I bent the metal, but there's two bits of this that I felt were of note, the most significant of which is the bracket to attach the bottom of the pan to the engine block.
First I put 'er up on the centrestand (centerstand for the 'mericans).
Then I took some draft measurements, then designed a template on the 'pooter (using newspaper layout software, fwiw) that I then cut and folded and put into place for a test-fitting. And those that want the final template (I had to tweak it a bit) can download a .pdf file here: http://www.camerapro.ca/image/bashplate.pdf
So I applied the template to the metal, and I cut and drilled and fiddled and test-fit and filed.
The challenging part, as I could see it, was attaching the upper part of the bashplate to the bike. I opted to bracket the things onto the GIVI crashguards. I didn't want to fiddle with the bolt that connected the two sides of the bars. Rather, I wanted to mount the thing to the bars directly.
However, I didn't want something that might rattle around on the bars and cause wear.
So here's where a little Canadian cultural ingenuity comes in. I took two pucks (cuz every Canadian has a few pucks lying in the garage) and froze 'em.
Then I drilled a 1" hole in the middle of the puck. I trimmed some of the edges of the puck until I had kinda a rectangular block with a hole in the middle, the block about 1 3/8" wide. I drilled 1/4" holes through the edge of what used to be the puck, then cut the puck in half. Voila, rubber mounting thingamagiggers.
This image does a pretty decent job of showing how the final mounting goes. Note that on the far (left) side I had to use washers. This is one of the flaws in my design: not enough space to work with. In the end, that's what led to the two pairs of holes on the upper part of the plate shown attached earlier.
Hint: freeze the puck first. Easier to work with.
Then I took an old hole bore and drilled three holes to help with a little ventilation to the oil cooler.
Now, the plate isn't totally complete at this point: I plan to add some flanges to protect the oil filter, but that can come later as a four-hole, five-minute addition.
This is clearly not a heavy-duty beast, but the rubber mounts at top and a fairly thin-grade metal bracket are designed to actually deform in case of a major hit, absorbing some of the energy rather than transferring it to the valuable bits. Kinda like crumple zones in a car.
Moreover, I could remove it - though I loctited the bejeepers out of the bolts - but I don't think I have to.
The oil drain plug is quite accessible, and the oil filter likewise.
I figure that if I need more protection underneath, I can add an extension plate just by bolting it on to the end... meaning I need only undo a few bits to get back to the current point for oil filter changes and the like.
Total cost: $25 CDN and about four hours of work, give or take. An hour of that was creating the template for the bracket and testing it.
I've since taken the beast off-pavement, including some high-speed gravel work, and low-speed slopwork. Since installing it, I've heard some definite "pings" as rocks and gosh-knows-what smack off the thing... and that's been on pavement as well as gravel.
Here's a slightly different view. Call this a "testing" phase.