Underbelly Exhaust On A Vfr?

[RDMcD]

For the past couple of years I've been thinking about replacing my stock exhaust and keep thinking how good an underbelly system would look. Unfortunately, there is no such thing available. Has anyone ever seen or heard of a custom made one? A v4 makes this a challenge and space is limited but I think I have a couple of designs that might work. My question is in which order to connect the cylinders. The stock set up for a VFR 800 with a180 degree crank is to join the diagonal cylinders two into one and then those pipes join into one. A 360 degree crank engine joins the front two cylinders and then the rear two cylinders. After studying pictures of the new 2014 800 I noticed it is set up like a 360 degree engine.

I'm pretty sure the new 2014 is using the same exhaust as the crossrunner in the picture.

Would that work on a 5th gen? If so an underbelly exhaust maybe easier to do. Any thoughts would be appreciated.

[Rush2112]

I believe the Crossrunner is tuned for more low and mid-range torque so back pressure is not bad and optimized exhaust scavenging flow at high rpms is less critical... neat concept, if executed keep in mind to screen the exhaust outlet or otherwise take into account the possibility of sucking debris into the exhaust during hard engine braking... especially on right hand turns if your thinking this would be a right side exit exhaust pipe. Ducati learned the hard way and I think Honda MotoGP copied Ducati and screened the exhaust outlets to keep the pebbles out

[AB-Oz]

a guy on this forum made an underbelly exhaust for his 5th gen a few years ago, try a poke around the 5th gen modifcations sub-forum it might still be here...

[AB-Oz]

here we go, I remembered who the poster was:

http://www.vfrdiscussion.com/forum/index.php/topic/19224-not-another-5g-undertail-exhaust/#entry218679

[Veefer800Canuck]

A trip in the WayBack machine!!!

[RDMcD]

Thanks ab oz for the link. I think I'd seen that long ago but hadn't been able to find it again. Nice simple design but may have been too loud. I would like to make something longer that starts at the front of the oil pan and ends before the rear tire, narrow enough to fit between the centrestand . Something like a Buell or a Panigale. This means new header pipes as well all done with stainless.

This is a rough idea of what I'm thinking.

[Dutchy]

Marzipan???

[RDMcD]

Ya, if I don't like the way it looks l just eat it.

Actually it's just kids plasticine that was sitting around.

[apexandy]

I know hardly anything about exhaust design really... but how important is it to get close to equal length primaries? I like the idea of an underbelly exhaust, and I'm sure you could make something like your model, but the front primaries would end up much shorter than the rear. Is that an issue?

Edit: Or am I looking at your model backwards?

[RDMcD]

Apexandy, after posting I realized that the pictures of the ducati and the model were backwards to each other and might cause confusion. The front and rears should meet close to the stock position, that was one thing I didn't want to change. I'm glad that you read my post, after following your impressive build, I couldn't help thinking that this exhaust would look great on your bike. Nice work!