Ok, for anybody who's curious about the stock VX800 exhaust, you shall be curious no longer. Except now you'll end up being curious about why the heck Suzuki engineers designed it this way.
Check the stock left side / rear cylinder exhaust:
You can see I've already cut it just before the little beauty cap, in the above pic.
Now a close up of that section:
That's looking down the pipe in the direction of the muffler.
A quick measurement of ID on the smallest pipe:
That's reading 1.25" ID. Slightly screwed up for the photo since I was trying to hold the calipers so you could read 'em. It's really 1.25" ID on the money.
Just to follow through on that thought, here's the other end of the same pipe, just before the muffler mounts:
That's reading just shy of 1.6". The inner pipe has an OD of 1.75 and is a 16 ga pipe.
Now let's go the start of the exhaust pipe, just where it leaves the engine. Still on the left side:
That's a solid 1.25" ID.
Now on to the right side of the bike / front cylinder, just after the engine flange:
That's a 1.25" ID also. It's about a 1.4" OD.
Now the right side, just before the beauty cover and where it goes 3 in 1:
Pretty much the same all the way through on the right side.
Here's a view down in looking from muffler towards the engine, where the 1.25" pipe dumps into the 1.75" OD pipe just before the muffler:
Last but not least, here's the right side pipe just after the engine:
Talk about screwed up. During the bending process maybe, the internal pipe ruptured so exhaust was flowing in the little pipe and in the outer pipe. Bad for efficient exhaust removal.
Based on comparisons I've made to other readily available bikes, the VX has significantly smaller exhaust pipes. A stock SV650 with 325cc per cylinder has a ~1.5" OD 409 stainless pipe that is significantly thinner walled than the VX.
My DL650 V-Strom has 1.5" OD 409 stainless pipes that seem to be about 18 - 20 ga.
So, is the VX stock exhaust too small for the engine size? Not sure.
Is my 1.75" OD 18 gauge custom system too big for the engine size? Seems like maybe a little.
1.5" seems too small though for the VX and the next step is 1 5/8" which is what I started with, but decided I didn't want 16 gauge (which is what I bought). Plus 1 5/8" is a pain to find bends and fittings for since it's non-standard.
And now for a tail teaser shot: