K&n

[Ironman883]

Are these the same thing

 

[Fire-medic]

A lot of VMax people use the K&N OEM replacement (I am one) w/the OEM airbox instead of the individual pod filters. Not seeing the part # on the box, no way to know.

 

[rreed]

A lot of VMax people use the K&N OEM replacement (I am one) w/the OEM airbox instead of the individual pod filters. Not seeing the part # on the box, no way to know.

K&N Engine Air Filter: High Performance, Premium, Powersport Air Filter: Fits 1985-2007 YAMAHA (VMX1200 V-Max) YA-1285​

 

[one2dmax]

If you run the pod filters you also need the dynojet stage seven jet kit. There are pro's and con's of those vs our kit.

 

[Davelaf]

A lot of VMax people use the K&N OEM replacement (I am one) w/the OEM airbox instead of the individual pod filters. Not seeing the part # on the box, no way to know.

Hi. I am wondering if you think the k&n filter is worth it, and could you tell a difference. I had jet kit put in that came with the bike. It was Dynojet, but I can't remember the number. I should have written it down. I remember it was expensive 400$? I've never had a good memory, so I won't know if I'm getting Alzheimer's in a few years. It sounds like you use the stock air box. Has anyone tried to build a ram air for these things??
Anyway thanks for any help, and I wouldn't ride any other bikes and enjoy myself as much as on a VMAX. I was looking at 2nd gen, but the $, weight, and height, I'm not sure. Bye again.

 

[Davelaf]

I guess Dynojet only makes 2, so mine has a 7 in it. It doesn't get great had mileage, but who cares.

 

[Jack Hammer]

I've got the OEM style K/N filter too. The original air box is actually a ram air but you can make it better.

 

[MaxMidnight]

I've got the OEM style K/N filter too. The original air box is actually a ram air but you can make it better.

You are saying a Gen I has ram air (i.e. forced induction) - explain please.

 

[Jack Hammer]

The throats of intake box passage square footages are significantly smaller than the surface area square footage straight down inside the box by a certain multiply = ram effect. High air speed becomes high pressure when it slows down, basic physics.

 

[Jack Hammer]

It can be amplified but the carbs need to be up to par. That can be done too by introducing more air under the faux cover. When your engine is still naturally aspirated with carbs, you can actually modify the OEM scoops to bring air underneath the faux cover and make sure the tail section under the cover is keeping the air in, not letting it escape. You can open up the areas behind the scoops or fabricate actual functional scoops. If you decide to keep the original scoops, open the face of the closed one. Only one of them is open at the face and direct the air streams towards the top of the faux.

You need to really understand what you are doing if you want to open up the air box intake passages. If you cut the top (typical mod) then if your engine is not built to breathe more, you are hurting performance. It took me a couple tries to get this right with my setup because I did open them up and I did increase open air pressure under my faux cover.

 

[MaxMidnight]

The throats of intake box passage square footages are significantly smaller than the surface area square footage straight down inside the box by a certain multiply = ram effect. High air speed becomes high pressure when it slows down, basic physics.

What you are describing is Bernoulli's principle which relates pressure, speed and height. Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or the fluid's potential energy. It is why a venturi can pull fuel into the incoming airstream

On the Gen I the intake charge is pulled into the carburettors by the piston descending. The key word is pulled and is at atmospheric pressure.
A ram effect is where a force is applied to push additional air. The key word here is pushed i.e. raised above atmospheric pressure to increase the volume passing into the inlet tract.
No such force is applied to the inlet of a Gen I airbox as to all intents and purpose it is in still air (which is why the float bowl vents are located on the top of the airbox}..

The one attempt at producing a ram air system was done by Rick Bachman who produced a system for the Gen I. His website doesn't appear to exist anymore but if memory serves well at best it gave a 3 bhp increase and you had to be travelling at illegal speeds to get that.
IMO hacking the OE scoops will at best keep the person doing it out of mischief for a while but do nothing to give a ram effect.

That's not to say modifications to the intake system can't yield benefits but that is a different discussion.

 

[Jack Hammer]

If you look at the formula itself, it does not contain a variable about push or pull. It is all about pressures, speeds and square areas. Increasing pressure at the throats of the box will yield better results marginally.

I built a go kart for myself 15 years ago. I fitted a Suzuki V2 1000cc superbike engine into it, kept the original air box and reshaped and enlargened the throat and pointed it forward. There was a clear change. That engine was fuel injected. Few videos in my YouTube channel.

 

[one2dmax]

I agree. The airbox and it's flow does not alter it in any way to make it a ram air or pressurized system. Just taking advantage of a great design that I am sure took many hours to create. I believe the volume of the box was more to address intake pulses and smooth them out so that the internal velicoty stacks could work at peak effeciency.

Our kit increases the airflow significantly with notable power increases but it is still not a ram air setup.
The old link using the internet archive: About Us