Firing Order And Pipes

I'm going to be welding up my own exhaust for the VFR, and am trying to make it work as well as possible.

My idea is to have each cylinder bank have it's own system, but the unusual firing sequence is throwing me off. I'm trying to mimic the looks of the Honda MotoGP system.

It makes sense to me to have the exhaust pulses spaced evenly to provide the best flow, but the setup doesn't allow that. How should I arrange my headers to optimize this? It looks to me like this engine runs like a pair of 270 degree parallel twins. Looking around at the new FZ-07 has unequal length headers. Is this the solution to this issue? Does it really even matter?

EDIT: I think I've misled you guys with what my goal is to do. I do not want a single exhaust exit. I do not want the two cylinder banks to ever merge if they don't have to. I want my rear cylinders to exit through the tail, and the fronts to exit behind the footpegs.

I'm definitely interested in this topic. It does seem like the VFR 180* engines pair different cylinders than the 360* RC engines. Although, I think the new 8th gen might pair the front bank together and the rear bank together before the final merge. And Ducati's GP bike has them paired that way. As far as I can tell it sounds like a 180* crank. The unequal length headers that you mentioned might be a factor.

here ya go bruh

good luck on your endevor

theres about 20 guys with cash in hand waiting for you to produce it

http://www.vfrdiscus...r-vs-the-motad/

Chip, 

I was looking for the answers to this a couple of years ago while designing an underbelly exhaust. Never got a definitive answer, so never built the exhaust. Someday I will.

http://vfrworld.com/...h built exhaust

This link show a 4th gen with a homemade system that is set up like a 360* crank would be. I've asked the original poster for an update. 

What year bike are you working on? 

I'm going to be welding up my own exhaust for the VFR, and am trying to make it work as well as possible.

My idea is to have each cylinder bank have it's own system, but the unusual firing sequence is throwing me off. I'm trying to mimic the looks of the Honda MotoGP system.

What model of VFR?

This is on the fourth gen, VFR750F.

I'm definitely interested in this topic. It does seem like the VFR 180* engines pair different cylinders than the 360* RC engines. Although, I think the new 8th gen might pair the front bank together and the rear bank together before the final merge. And Ducati's GP bike has them paired that way. As far as I can tell it sounds like a 180* crank. The unequal length headers that you mentioned might be a factor.

I took a look at Ducati's setup, but their engine still operates essentially as a twin. They use a 360 degree crank with a 'Twin Pulse' firing order, firing each bank at once. The pipes only merge from each bank of cylinders. However, this look is exactly what I want.

[image: 2014-ducati-gp14-unveiling-munich-audi-9]

I took a look at how the crossplane R1, which essentially works in the same fashion as our v4, and they use normal headers and joining methods but then splits into twin cans. With the last few links you guys gave me it looks like I might just have to end up with a 4-2-1-2 exhaust to have it work properly, but I really want to keep these two cylinder banks separated to keep weight and complexity down.

Eighth gen vfr800. Pairs the front primaries together and the rear primaries together, just like a 360 crank..... Not much difference in performance. My two brothers header does opposite corners together. Great top end....

I took a look at Ducati's setup, but their engine still operates essentially as a twin. They use a 360 degree crank with a 'Twin Pulse' firing order, firing each bank at once. The pipes only merge from each bank of cylinders. However, this look is exactly what I want.

not sure that's true. It certainly sounds like a 180* setup. I think in the beginning they tried some different setups with their crank arrangement. But… you could be right. Im definitely no expert. Paging Busylittleshop… 

I took a look at Ducati's setup, but their engine still operates essentially as a twin. They use a 360 degree crank with a 'Twin Pulse' firing order, firing each bank at once. The pipes only merge from each bank of cylinders. However, this look is exactly what I want.

not sure that's true. It certainly sounds like a 180* setup. I think in the beginning they tried some different setups with their crank arrangement. But… you could be right. Im definitely no expert. Paging Busylittleshop… 

It sounds similar to a 180 setup, but not quite. Listen close on the onboard videos, they sound sharper than the Yamaha and sound like it revs a little higher at the same rpm. They have always used a 360 degree crank. Early on their firing order was akin to the Honda's screamer engine, but then reverted to the Twin Pulse after engine reliability was improved, because it was a setup that was easier to ride on. 

"Therefore we designed an engine with four round pistons which, thanks to a simultaneous two-by-two firing order, reproduce the working cycle of a twin. This will generate the 'big bang' effect, making the rear tyre work in a way that extends its duration and improves rider feeling when exiting curves," -Ducati Corse managing director Claudio Domenicali