Stacks

[bsmitty902]

How should the velocity stacks be arraigned. Just cleaned my filter and wanted to know how they should be. Right now the short are in the frt and tall are in the rear. Read on another post that you could switch them up this way Left frt short, right frt tall, left rear tall and right rear short. How will this change performance?

[Darth Bling]

Put the short ones up front and the long ones in back. :fing02:

Longer velocity stacks help with higher rpms, shorter velocity stacks help with lower rpms. That's why Yamaha has that variable velocity stock system on the R1 that makes the stacks taller at higher rpms. On your VFR, it's probably won't make enough of the difference if you mix the stacks up.

[Baileyrock]

Put the short ones up front and the long ones in back. :fing02:

This is NOT how Honda whats them and several people here have had ride issues when installed incorrectly.

It is not short front or rear, I need to find the correct set-up and add it shortly.

Here's what I found in the search area and the arrangement of every stock VFR I've ever opened!

"After reading another post though, I switched my stacks to this configuration which seems to be how the manual depicts them and how they are installed at the factory.

Left Front: Short

Right Front: Tall

Left Rear: Tall

Right Rear: Short

I don't know why this makes a difference, but it does seem to affect how the bike runs. So if you are running the stacks as front/short and rear/tall, and are experiencing low speed high rpm surging, then I suggest trying the stacks in this configuration. It worked for me!"

[bsmitty902]

I remember hearing this awhile ago. I'm going to switch to this and see if I notice any differance.

[Baileyrock]

I remember hearing this awhile ago. I'm going to switch to this and see if I notice any differance.

Here is a link to the one thread I found the info in:

http://www.vfrdiscussion.com/forum/index.p...1&hl=stacks

[Tightwad]

I took my air filter out for the first time since I bought the bike with 14K on it. As far as I know the box had never been opened. My stacks were set short in front, long in back

I wonder if they have a "Random Stack Position" generator that dictates install position.

[BartmanEH]

Put the short ones up front and the long ones in back.

This is NOT how Honda whats them and several people here have had ride issues when installed incorrectly.

It is not short front or rear, I need to find the correct set-up and add it shortly.

Here's what I found in the search area and the arrangement of every stock VFR I've ever opened!

"After reading another post though, I switched my stacks to this configuration which seems to be how the manual depicts them and how they are installed at the factory.

Left Front: Short

Right Front: Tall

Left Rear: Tall

Right Rear: Short

I don't know why this makes a difference, but it does seem to affect how the bike runs. So if you are running the stacks as front/short and rear/tall, and are experiencing low speed high rpm surging, then I suggest trying the stacks in this configuration. It worked for me!"

Since the topic of velocity stack arrangement comes up quite a bit and folks are liable to search the forums and find threads like this one, I thought I'd resurrect this thread and correct the information. I gotta disagree with BR on this one (and that's saying something 'cause I respect the guy... props, BR). After pretty extensive research in this thread Surging Surging Surging!, the conclusion is that the official word from Honda is that the velocity stacks are to be both short in front and both tall in the rear in agreement with the parts microfiche (which is an industry standard guide used to disassemble and reassemble any mechanical device).

[soichiro]

Short in front. Tall in rear is how my bike was shipped.

[Misspent Youth]

This should definitely stay in "Electrical," now that Tightwad has posted.

[kaldek]

I'm gonna stir the pot again here, and say I believe that the Short-Tall, Tall-Short arrangement is actually right. Here's why I think that's the case - bear with me now!

The firing order on the VFR800 is lumpy. It goes 1-3, big pause, 2-4. Cylinders 1 and 3 are the rear bank whilst cylinders 2 and 4 are the front bank. So it's almost a V-twin power delivery, but not quite.

If you put your intake stacks as Short-Tall (cylinders 2 and 4) and Tall-short (cylinders 1 and 3), then at any given rpm one of the two power pulses from each bank of cylinders will be more optimum than the other one. However the pulses are so close together that it shouldn't be noticeable. As engine speed increases, the more powerful pulse will move from one cylinder in that bank to the other, keeping it fairly nice and even.

If we change the layout to Short-front and Tall-rear, then each BANK of cylinders will work best at certain rpms. So regardless of rpm surely the engine will vibrate more, because the power delivery would be optimum on one grouped power pulse and much less optimum on the other grouped pulse. One would imagine this could cause weird acceleration and deceleration of the crankshaft, much like a misfire might.

Am I making sense? Or am I mis-reading the VFR crankshaft phasing?

[Baileyrock]

I have no issue being right or wrong on any issue, what's important is that members get the right info from whoever!

I've opened at least 6-7 Vtecs and everyone had the offset stack set-up(short/tall front...) and at least 3 were new unmolested bikes. This does NOT mean that it is correct!

It seems Honda sent them out both ways as owners have both set-ups from the Factory.

The thread I mentioned in one of my early post seemed to show how much of a difference it made from one owner, but who knows as people swore on it in either direction.

All of my bikes still run the offset stacks w/no surging issues(85k worth on my 02).

Keep the info coming folks!

[RustyA]

My '07 has both short in the front, and both tall in the rear. That's how it was when I first looked that it. That's the way it came from the factory. Even took pictures of it.