Airbox mods list- what I did

[nidyanazo]

Just thought I'd share with ya'll a list of mods I did to the airbox.

So I have a K&N filter (single large type) and noticed that there is extra lip around the area where air enters. Remove the faux tank cover and look at the airbox.

On top of it, there are screws holding the actual little air funnel piece to the airbox body. Remove it, and look down at the rectangular opening, where the air enters.

You will see you can trim a full 3/8" off of the sides of it, and a corresponding 3/8" off of the filter lip. This effectively widens the air entry point, allowing for more air to enter.

I then drilled holes in the little air funnel piece that needs to be removed to see the rectangle hole where the trimming occurs.

On the underside of this air funnel piece (again it's the very top part that screws to the airbox lid) you can trim the ridge running down the center line, and drill holes all over it for more flow.

Moving inside the airbox, I pulled the main lid to expose the air filter. Looking down, you can see the rubber funnels on each carb. I carefully trimmed a little crescent / half moon shaped cut on each one, where the rubber touches the air filter. This allows air to directly flow from the filter into the funnel. I did not reduce the overall height of the stacks.

Then I removed the little velocity stacks connecting hoses, and pulled the filter. Leave these parts off when you re assemble!

Under the filter, there are 3 screws at the back of the box, and you can remove a plastic piece that the filter sits on. Doing this creates more volume in the airbox.

Finally under that, I plugged the hole at the bottom of the airbox.

Result is noticeable. I lost a bit of low/mid, but gained high rpm power. This is normal due to the v-stack cutting. It's why My R1 has the electronic v-stacks that move up and down depending on rpm- but since they are fixed in position on the max', cutting them down just permanently alters the airflow characteristics.

Another sweet effect of all this is you can hear those suckers 'gulping' the air- put it in 3rd gear at 3000rpm and crank the throttle and you'll really hear the intake sound!

I'll get a little video later on. Well worth the time spent, especially with a little carb tuning. Combined with the washer under the needles trick it really added to the bike's power delivery!

 

[Traumahawk]

Do you have pics of this?

 

[johnpclynch]

When you plugged the hole at the bottom of the airbox, did you re-route the crankcase breather pipe?

I went a few steps further. I got rid of the Y piece, cut the airbox opening (and filter) to its full potential and then punched a hold in the faux cover.
I also replaced the velocity stacks with shorter ones that keep their shape

And you're right about the intake sound - you can really hear those guys gulping

 

[one2dmax]

You're about 25-30 years behind on your testing. Pretty much all those mods were tested the first year the bike came out. What can work is lifting the "Y" piece by adding washers/shims under it. This still gives the airflow some velocity but add's more volume. Then removing the "Y" section or drilling holes through it. Of course then enlarging the opening in the plastic lid to match the opening of the actual filter. I would highly suggest AGAINST plugging off the PCV system as that helps to pull a vacuum on the pistons to help make more power and burn cleaner.

Stave seven hybrids have been tried as well with longer and shorter stacks. Even adding the filters to the tops of the velocity stacks or simple copper extensions (works well if you are wanting to run the pod filters).

Our kit is a hybrid of that and even it went through a number of changes before we settled in with the current design. Our current design tends to make the same peak power as the stage seven without giving up the bottom and mid range power. Our kit has also been tested (by other companies not affiliated with us) and made more power then even flatslide carbs (though that is not something we advertise it to do).

 

[davesax36]

You're about 25-30 years behind on your testing. Pretty much all those mods were tested the first year the bike came out. .

Buzzkill... :biglaugh:

 

[Biker Dash]

Lifting the "Y" cover with washers, does this hurt low end any? I kinda like that low end the Max has.

 

[Traumahawk]

Lifting the "Y" cover with washers, does this hurt low end any? I kinda like that low end the Max has.

You can see my dyno runs....I picked up almost 3 hp on the top end (no losses below) by removing the Y.

 

[Diablotin]

I ended up adding a shim on the needles after lifting the y of the airbox. It gives a very nice low-mid range. Without the shims I lost my low end power which I loved.

It runs pretty well this way but I'm sure Sean's kit is the way to go.

Sent from my SM-N9005 using Tapatalk

 

[Fire-medic]

If I didn't already have a Dynojet Stage 7 kit, I would buy Sean's kit, it's tested, proven, and you can ask the manufacturer questions!

Still, it's fun to experiment and to find something on your own.

 

[Biker Dash]

You can see my dyno runs....I picked up almost 3 hp on the top end (no losses below) by removing the Y.

I tried running without the "Y" before, and it felt sluggish to me down low, compared to stock, and the gains up top were not so noticable. (I guess that when you have a hundred at the wheel already, 3hp is not that noticable at the tailbone)

 

[Traumahawk]

Well 3 hp is the lower end of what you can feel. If you have a free flowing exhaust, you get really good gains from tricks like this. I picked up 3 with a kerker 4-1, and 3 from the Y, so an easy 6. No rejetting.

At 9500 rpm VS stock exhaust there was 13 extra hp.

With the stock exhaust, the exhaust is more restrictive, and so you dont get those benefits.

 

[Mr. Max]

I have UFO full exhaust and stock jets etc, it runned OK jus as is, maybe little signs of rich condition at cruising speeds but nothing major. I had small crack in bottom of airbox (where is screws) and I bought good used one with K&N filter in it. I washed and oiled filter and installed this "new" airbox, and now bike runs like shit. It actually speeds up when I reduce gas to point that it is barely giving any throttle and jerks (I don't know if thats a correct word) at cruising speed at 2-3k.
Might it be that it was leaner with that cracked airbox? It really was a lot better with it. I have bought 150 main jets from Sean, I'm going to install them tomorrow and see what happens. Maybe I should try to lift that Y on airbox lid to get more air in it? I'm not looking for more power, otherwise I would have bought Seans jet kit long time ago. Just like to get it running OK with that exhaust.

 

[Fire-medic]

Which UFO? The 4/1 Dragstar? (see attachment) That's pretty-much a straight-through (very little baffling, and no real muffler) exhaust. You need to re-jet for that. I am surprised it runs w/any degree of drivability on stock jets. I think you should be able to use 147.5 jetting, but since you have the 150's try 'em.

Maybe your original cracked airbox was allowing more air? I think leaving the one you got w/the K&N & changing to the different jetting will help, but I bet that you will have issues until you get w/a full needle/jet set for your pipe. FYI. I was able to retain the VBoost which the Dynojet Stage 7 kit (which I have) says to eliminate (synching the carbs is also much easier w/it in). Captain Kyle has found he can run the VBoost w/a jet kit also. Among Sean, Dannymax, and Kyle, you have lots of experience in the VMax carbs dep't. There are also other members who can weigh-in as-well.

I hope you are using earplugs w/the UFO, you can cause permanent damage to your hearing from one exposure to prolonged excess noise. "Just say, "no" to excess dB!"

I have UFO full exhaust and stock jets etc, it runned OK jus as is, maybe little signs of rich condition at cruising speeds but nothing major. I had small crack in bottom of airbox (where is screws) and I bought good used one with K&N filter in it. I washed and oiled filter and installed this "new" airbox, and now bike runs like shit. It actually speeds up when I reduce gas to point that it is barely giving any throttle and jerks (I don't know if thats a correct word) at cruising speed at 2-3k.
Might it be that it was leaner with that cracked airbox? It really was a lot better with it. I have bought 150 main jets from Sean, I'm going to install them tomorrow and see what happens. Maybe I should try to lift that Y on airbox lid to get more air in it? I'm not looking for more power, otherwise I would have bought Seans jet kit long time ago. Just like to get it running OK with that exhaust.

 

[Mr. Max]

Its 4-2 classic megaphones with those smaller endcaps, its not loudly loud but makes some noise in neighborhood for sure. I have to look closer that old airbox, I dont want to use it because it let air in without filtration, not much but still. Now it feels to be super rich, wasn't bad at all with that old airbox and I was wondering whats all the fuzz about rejetting after bigger headers. Well I guess now I know lol. Same time I installed new wires to ignitech so I got vboost connected to it, but I think I couldn't mess anything up in there (just made my boost work again) so it must be that airbox.. I think.

 

[Mr. Max]

I put 150 mains in today, and 2 shims under that Y-piece (dont know if it really works or not) but bike felt a lot better. I did only a quick test run before I had to go to work, hope it works on highway too!

 

[nidyanazo]

For my setup, in the thinner air (elevation 5,500') my mods made a nice difference. Cool to hear others have seen /felt the benefits also! I'll get those photos today after I finish my starter clutch rebuild.

 

[nidyanazo]

This is what I want next to finish off the airbox mods- Just not thrilled with the visual design of it.. Bun functionality wise, this thing is rad. I wish it matched my aftermarket side scoops better though.

 

[srk468]

If you've got Sean's kit there's a way to pick up a few more hp, pull your scoops off and cut out the plastic panel behind the screens. It's not ram air but it directs more air under the lid and to the airbox, I picked up an average of 1.5mph in trap speed through the quarter doing that and it's free. I can post pics later if anyone wants.

Sent from my HTC6500LVW using Tapatalk

 

[Redbone]

Take a look at KJShover's Vmax and check out the nice mod he did on his faux tank. I'm sure he has no issues with air into his Morley air box!
I was toying with the idea of cutting in 3 angled vents (per side of faux tank) about 1" wide by 3" or 4" long outside of the top of the filter. The idea was to not have a direct path to the filter for water to run into the air box. The vents would be backed with SS mesh. That should bring in a bunch more air and add a little different style to the faux tank.

 

[stobrien]

My max runs good but a little Rich, if I raise the Y box 3/8 to 1/2 will it lean things out?

Does any one have pictures of there Airbox mods even the raising of the Y box.

I am better with visual than I am a long write up.

Thank you