Air Intake - Starving for air

[Lyle Laun]

Looking for some advice on the air intake. My bike has an F4 windsheild, Baker Airwings, and an oversized carbon fibre fuel tank. It appears that the design of the oversized fuel tank is starving the air intake when running WOT in 5th gear. It doesn't do this with the factory tank but i prefer the oversized tank. I have shimmed the front & back of the tank and it is pretty good but not totally fixed, still a bit of an issue if you want WOT at anything above 85mph.
My question is - is there anything I can do to get more air ? Assuming most of the airflow is from the front of the fuel tank ?

Much appreciated
Lyle Laun

[Gavin_Sons]

Try opening the gas cap to make sure it's not a tank breather line.

[Lyle Laun]

Thanks,
I've done that, it's not a vent line problem.

[Chrisj CMA]

K&N air filter may increase airflow

[BonS]

Do you have a fuel filter? Is there a kink in the fuel line? The starvation could be a slightly too long length of the fuel line causing a kink when the line gets hot and expands or insufficient fuel flow due to a too-restrictive fuel filter.

[Lyle Laun]

New K&N filter.
No fuel filter in the line.
Fuel line length is correct.
I believe It's starving for air due to the shape of the oversized (10 gal) fuel tank. It doesn't do it with the factory standard tank. It's improved greatly by shimming up the tank but still not totally cured.
I'm just looking for a way to funnel some more air in under the tank.

Thanks

[The emperor has no clothes]

Whoa ! That's one big tank. I don't have any idea if it will work. But I was thinking maybe some Memphis Shades Lowers and angle them outward so that it scooping air to the center. It's going to look kind of weird though.

[pago cruiser]

Don't know if this will help, but a few bikes have air ducts from the front of the tank/fairing leading back to the air cleaner.  My ST1100 has one these, and the GL1800 has two.  As does that new Turbo 300 HP Kawi as well. Any way to add something like that?

Would love to see a pic of the tank.

[R J]

Yes Sir, can ya add a couple or three pictures for us to look at?

If you think it is a bad flow of air to the breather, you might have to add some wings or something similar force air into the breather area.

This might be a good governor for ya to not get a citation of SPEED.

MGM had a couple of disks under the front of the tank to draw more air.      Ya might have to look in that area.

[BonS]

Whoa ! That's one big tank. I don't have any idea if it will work. But I was thinking maybe some Memphis Shades Lowers and angle them outward so that it scooping air to the center. It's going to look kind of weird though.

I have them on my Interstate and they're angled inward because they have to be to avoid interference with the pods at full lock. They indeed do dump a lot of air toward the radiator but I'm in a still pool of air so I doubt much will be added to air flow underneath the tank.

I'm just looking for a way to funnel some more air in under the tank.

How does it run without the windshield? That should allow a healthier stream of air to jet underneath the tank. I know of gas leak issues with your tank but never heard of air starvation issues.

[Lyle Laun]

Thanks for all the replies and help on this. As it doesn't look like there is an easy fix for this, I think I will probably just put the original tank back on the bike.

Much appreciated
Lyle

[R J]

HOW ABOUT A PICTURE SO WE MAY HAVE AN IDEA WHAT IS GOING ON.

SORRY FOR HOLLERING, BUT MY GRAND DAUGHTER HAS BEEM POUNDING ON THE KEYBOARD.

[Lyle Laun]

RJ
I'm running off my IPad and don't know how to post pics from it.

[Gryphon Rider]

RJ
I'm running off my IPad and don't know how to post pics from it.

What I've found is quick and easy from my iPhone is to sign up for Photobucket and use their app to upload photos from your device and use their tool to copy the location and paste into your message.

[Karen]

Second the K&N air filer idea, it may allow you to keep your larger tank.

[98valk]

Since the OEM air box takes air from the rear of the air box, allowing more air into the front might be causing a high speed air stream going past the rear air box opening which actually is reducing the amount of air the engine can pull in. the higher air pressure stream going past the opening is higher than the engine vacuum draw on the opening. suggest lower the front of the tank and only raise the back. check to see if the tank design is partially blocking the air box opening. take the air box lid off and remove the baffle that is plastic welded to the lid. this will allow more air in.
I actually blocked off the oem opening and opened up the front of the lid, but this requires re-jetting.

http://www.valkyrieforum.com/bbs/index.php/topic,8248.0.html
http://www.valkyrieforum.com/bbs/index.php/topic,51259.0.html

[Lyle Laun]

Thanks CA, I've tried it with the front & back of the tank both lifted and also with just the back of the tank lifted. Seems a bit better with both the front & back lifted. I don't think that I am wanting to go down the air box lid modification and I probably will just put the factory tank back on.

[98valk]

I know nothing about that tank.
some thoughts....
 Are u sure there is zero fuel restrictions in the supply/petcock and the tank vent connection tubing?
could something be blocking the tank vent inside of the tank?

[Lyle Laun]

CA
I will check those items again to be sure.

Thanks

[Firefighter]

I wouldn't think your larger fuel tank could have much to do with air intake volume unless it is up against the intake and actually sealing off the air entrance. I would think that even though air pressure might be a pound or so lower behind an obstruction, there should still be plenty of air pressure for our 1500 cc engines.

I would think something else to do with the new tank is the cause.  I'm no expert but can't see that being your problem. Hope you figure it out.

[Lyle Laun]

Thanks to everyone's help regarding my Starving for air at WOT in high gear. I think I've got it about 98% cured and will leave it alone for fear of going too far.
Here's my update, not sure if it will help others:
Installed a 10 gallon carbon fibre tank on one of my standards. This tank is a slightly different shape than a metal 10 gallon I have on my other Tourer. The bike with the carbon fibre tank would "bog down" under WOT in high gear. I did the following:
- rebuilt the cards. They weren't too bad but needed done. Didn't cure the bog
- replaced the K&N filter, left out the foam thing. Didn't cure the bog
- checked the vent line, it was fine. Didn't cure the bog
- already running a Pingel & the fuel line is good, no inline filter or Dan Marc
- lifted the back of the tank up 1" - things improved but not cured
- Lifted the front of the tank up 1/2" - better yet but not cured
- removed the Kury chrome cover for the bolt on the front of the fuel tank plus the two plastic side covers on the front of the frame - slight improvement but not cured
- got serious and bought another airbox lid, removed the baffle plate as per CA's suggestion.

Huge difference, I think I've got it about 98% cured. Tempted to cut a V notch in the back of it but will leave it alone for now.
A big shout out to CA, Pago Cruiser, and all of you that contributed !
Lyle Laun

[pago cruiser]

Lyle,
Glad you almost have it solved; sometimes ....almost... is as good as it gets    Would you mind if I hosted and posted your tank pics on the site?  They are pretty impressive.

[Patrick]

I guess my recommendation would have been to do what you did by raising the tank, I'm wondering if you could raise the front another 1/2".

[Lyle Laun]

Patrick:
Considered raising the front another 1/2" but was running out of room regarding handlebar turn radius.

Pago Cruiser - go ahead and post the pics if you like.

Thanks guys, much appreciated

[Patrick]

Patrick:
Considered raising the front another 1/2" but was running out of room regarding handlebar turn radius.

Pago Cruiser - go ahead and post the pics if you like.

Thanks guys, much appreciated

OK, thought there might be such a problem or you have already done it.

[98valk]

Patrick:
Considered raising the front another 1/2" but was running out of room regarding handlebar turn radius.

Pago Cruiser - go ahead and post the pics if you like.

Thanks guys, much appreciated

I think u should try lowering the front of the tank to stock and raise the back up more if u can. see if that makes any difference.

[Lyle Laun]

CA
I had the back raised 1" before I raised the front and found that it seemed to run better with the 1/2" spacer in the front than without.

Thanks
Lyle...

[pago cruiser]

Here's the pics Lyle sent.  Pretty cool.
Dibs if you ever decide to sell one!







Clean looking Valk as well. 

[R J]

Set your Baker Air Wings to blow air in on top of the air box.

In other words, set the rear edge all the way toward the tank.

That way the front will catch the air and toss it into-wards the air box.

If all else fails, put a taller set of risers on the h'bars.

Like maybe the risers off of a Harley deuce.

That was what I had MGM when I sold him.

You have to knock the tit off of the bottom of each stem.

 

[Jess from VA]

That tank is..... pregnant. 

[Joevalk]

Sometimes when spraying the k&n filter with the oil that is supplied, if you saturate it too much it will starve the engine from airflow. Try a stock one and see what happens.

[Lyle Laun]

JoeValk:
I had the same thought, and did exactly that. Didn't cure it.

Thanks
Lyle...

[BonS]

That tank might go really, really well with Beetle Bags. This picture makes me think that the standard tank looks simply too small.

[Joevalk]

Bueller? Bueller? anyone? anyone?

what did you figure out?