Drilling the airbox

[SANDMAN5]

I was reading some ancient stories on the Valk and came across a line
that mentioned drilling holes in the airbox lid to get more air into the
engine....or at least to give it an easier entrance. Makes sense to me,
like flipping the breather on an older car. I don't remember anybody
mentioning this before. Was it a bad idea? Did anybody do it and end
up having trouble with water getting in? Anybody STILL doing it? I'm
thinking about giving  it a try. What size hole would be best? I'll also
put a small washer under the front of the tank, maybe 1/8 inch at most.

[Warlock]

Most has found to leave it stock. Most had problems with it and ended up patching it back up. The easiest mod is to put a 1/2 spacer under the front and this allows more flow.
David

[98valk]

scroll down to my posts. U will need to re-jet and dyno tuning.

http://www.valkyrieforum.com/bbs/index.php/topic,8248.0.html

[Jess from VA]

Bob, I do not know from personal experience, but everything I've read leads me to believe it is a poor idea, with little to gain and much to screw up.  With all the gearheads around VRCC, why is this almost never discussed??   FWIW   If you are rejetted sufficiently, a K & N without prefilter will flow as well as you need. Some do this without rejetting, but I have read of unjettted Valks being leaned out because of no prefilter.

[Chrisj CMA]

Most has found to leave it stock. Most had problems with it and ended up patching it back up. The easiest mod is to put a 1/2 spacer under the front and this allows more flow.
David

the spacer was to go under the front tank mount to raise the tank a bit not to raise the lid of the airbox

[The Purple Haze]

the spacer was to go under the front tank mount to raise the tank a bit not to raise the lid of the airbox
 
I believe that is what he meant.  BigBF sells a great spacer for that purpose. http://bigbf.com/product_sale/
 

[Thunderbolt]

I don't have any personal experience either, but it seems that all I ever read on it says it causes more trouble than it is worth.

[SANDMAN5]

OK, thanks, ya'll. I kinda figgered that's why it wasn't talked about a whole lot.
I'll still probably raise the front of the tank a little, but I'll leave the airbox alone.
The K&N is enough.

[Warlock]

Most has found to leave it stock. Most had problems with it and ended up patching it back up. The easiest mod is to put a 1/2 spacer under the front and this allows more flow.
David

the spacer was to go under the front tank mount to raise the tank a bit not to raise the lid of the airbox

Forgot to say gas tank, but if you have pulled enough air boxes you'll realize a 1/2 spacer on the air box itself want work at all.

[FLAVALK]

Most has found to leave it stock. Most had problems with it and ended up patching it back up. The easiest mod is to put a 1/2 spacer under the front and this allows more flow.
David

the spacer was to go under the front tank mount to raise the tank a bit not to raise the lid of the airbox

ACE hardware has a white nylon spacer 1' diameter x 1/2" thick with 3/16" hole that fits perfectly with no modification. A pack of two is less than $1. I painted mine black

[Ricky-D]

I don't think that a gas tank spacer has any benefit whatsoever except maybe a psychological boost  to the "seat of the pants dyno".

The reason I say this is the FACT    that the air intake is facing rearward on the airbox.

If you were to raise the rear of the gas tank it would make more sense.

 

[Hellcat]

I don't think that a gas tank spacer has any benefit whatsoever except maybe a psychological boost   to the "seat of the pants dyno".

The reason I say this is the FACT    that the air intake is facing rearward on the airbox.

If you were to raise the rear of the gas tank it would make more sense.

 

I don't know if it works or not, but the theory is not necessarily flawed. A bigger opening at the front of the gas tank would allow more air in, which would be forced between the top of the air box and the bottom of the gas tank at a higher pressure due to the larger difference of space front to rear.

Therefore more air would reach the reach the rear of the air box at higher pressure.

So the theory does in FACT   make sense. Whether it works in practice I have no idea.

Now, on an Interstate with a full fairing, that hole doesn't take direct airflow, so the theory seems less useful.

[Tundra]

I know two who have drilled/modified their airboxes. Both "repaired", patched, or taped the hole to go back to the stock box.
  
Want more air? Go K&N and remove your pre-filter...be done with it. Ifin you aren't thrilled with your results and fussin with your pilots to get it right, put it back in.
  Pre-filter, no pre-filter can be as contraversial as tires and oil. I run mine this way as many others, works for me With my headers and air filter I needed to richen it up a little.

[R J]

I don't think that a gas tank spacer has any benefit whatsoever except maybe a psychological boost   to the "seat of the pants dyno".

The reason I say this is the FACT    that the air intake is facing rearward on the airbox.

If you were to raise the rear of the gas tank it would make more sense.

 

Hey Grasshopper, why you think this theory no work?

How many Camaro's have seen running around with the rear of their hood raised from the factory, or Doge Ram Hemi's with the same style hood?    Trust me Grasshopper, it works...........

PS: leave the firkin airbox alone, & don't ask how I know.

[Mikey]

Fact of the matter is that whenever you build pressure under the tank, it will help it breathe better. The back of the tank would decrease pressure under the tank (think of it like an airplane wing, if you will). If you wanted to get nuts with it, I suppose you could build a foam "dam" on the rear end of the airbox, and lift the front of the tank so that the air goes in and has more resistance to escape.

[Duey]

 

[R J]

Give him a stoogie, he is correct.

The spacer is just a reverse of this, & should shove more air into the airbox.

I know MGM woke up a little bit when I did it.

[greggh]

The spacer is there to help give clearance between the tank and the Velocity stacks on the top of the carbs.
If you raise the tank this way, give thought to adding some extra rubber under the tank around the frame to help put support back to the bottom of the tank instead of having all the support of the tank rest soley on the font mounting flange.

The Weight of the tank and gas could cause a stress fracture on the front mounting unit.
Just my 2cents

[John U.]

The spacer is there to help give clearance between the tank and the Velocity stacks on the top of the carbs.
If you raise the tank this way, give thought to adding some extra rubber under the tank around the frame to help put support back to the bottom of the tank instead of having all the support of the tank rest soley on the font mounting flange.

The Weight of the tank and gas could cause a stress fracture on the front mounting unit.
Just my 2cents

I agree with your comment about tank support. Even though I was assured the tank would not wobble from lack of support at the frame rails, I figured those rubber pieces on the frame are there for a good reason. I found that short pieces of the hollow "noodles" the kids use in swimming pools did the trick very well. They can be easily trimmed to get the righ size and shape.

[R J]

They might have used the spacer for stacks on an I/S, but the Std/Tourer did not need a spacer to add stacks.

Littler  tank.   Ya put an I/S tank on any model w/stacks ya need the spacer.

[Udo]

I´ve added stacks to my Standard. Without a spacer it´s really close. I´ve added a spacer, maybe 3/8". Without the spacer there was room for just a sheet of paper, between the tank and the stacks.....