Hey Scottie Mac or Gabe

[trout]

You guys seem to be the knowledgeable around here, please clear this up for me.

THis has nothing to do with the HONDA or YAMAHA being faster better whatever, just general engine question.

Does running your air box lid off lead to/cause/contribute to engine failure/greater wear?

I understand an engine is basically an air pump, so more air in and more air out should equal more power, BUT I am NOT a racer, I dont care if I have the fastest quad, or the first up the hill. But I do want more GO if you know what I mean. But im concerend that if I take the airbox lid off, sand (specifically) could get in to the air intake...............but I want the power, BUT will I really feel the power difference with the airbox lid OFF and Spark arrestor out? Basically is it worth it.

On the Honda there is essentually 6 clips holding the airbox on, that seems like a alot, so Honda wanted that lid to stay there............WHY?

Thanks for you time

trout

[Shawn H]

I'm neither of who you asked for but from what I have heard is that you do need some sort of restriction with part of a lid.
Now on a side note I ran my Z450 stroker with no lid for ever.

If you routine maintance your filter and run a outerwear you will be fine with no lid. I also smear a light coat of grease inside the air boot to catch any small debris that has made it pass the filter.

[trout]

Yes Im with you on the restriciton thing, I was actually thinking of drilling some holes in the airbox lid cover and then covering the holes with some thing like panty hoes, or window screen mesh, to create a barrier for dirt particles. Kind of Rube Goldberg-ing if you will.

Trout

[quadrcr161]

outerwears has an airbox lid, it is the same type of mesh that the filter covers are made from but it is an actual lid. you might want to look into that.

[trout]

Well I just ordered the TRX 450R outerwear from Nacsracing, had it overnighted so should be here tomorrow. Hope that is a good one, it was only 20$+shipping(probably 15$) but I want it NOW!

That looks like a good compromise, he says (nacs racing) that if the stack main is 118, then with the baffle out and The outerwear on should only need like a 120-128, that is way off of what was posted on here from Sparkys thread, they were talking like 180 or so, and my dealer says 140, so everyone is different, what the hell is a guy supposed to do? Buy 40 jets?

why cant we get a solid answer on this.

What jet size for no airbox lid and no spark arrestor?

scottie? Gabe??

thanks
Trout

[quadrcr161]

once you modify the airbox and exhaust, you will have to rejet it several times, esp during season changes. you might want to look into a kit with several main jets to keep on hand. or put it back stock.

[Shawn H]

Well I run a 190 but thats piped,cam,and HRC lid. Know one knows for sure where you should be its all trial and error. keep going up until it misses and back off 1 size.

[trout]

what do you mean by "misses"

trout

[Scottie Mac]

Basic rule of thumb is that if you remove the airbox lid and rejet, you should "feel" a sligth advantage. It IS NOT going to be night or day difference, but still. I race MX and I never run an air box lid on. I have a K&N filter that uses an outerwear and have had no issues. The main thing you need to remember is that you NEED to constantly clean and oil your air filter, just like you need to change your oil and filter a lot on the motor.

As far as jetting goes, good luck. I do think you would be way lean though if you have a 120-128 main. I do not have any jetting experiance with the 450R, but I do know that most people who run an airbox lid off and HRC end cap (less restrictive) are in the neighborhood of 180-190 main jets.

Is there anyone on here who has just an open airbox and end cap (without the HRC cam) that can give trout a starting base point?

Good luck,
Scott

[PJK 450R]

I have the HRC kit,Sparks pipe and air filter. Im running a 190 main, 50 pilot and 5th clip on the needle. It works for me here in NJ, but keep in mind temperature,elavation,humidity etc. affect your jetting. hope that helps.:D

[86atc250r]

Don't fall into the trap of believing "more is always better".

Just like running without an exhaust system, opening the intake side completely may result in a power loss as well.

Although I haven't performed any testing on the 450R, on the 400EX, completely opening the lid actually resulted in a top end power loss (regardless of jetting) - believe it or not.

In my experience partially opening the airbox is the way to go - similar to the HRC lid or cutting a hole in the lid and installing a "vent".

Also completely opening the airbox lid exposes the filter element to anything that can find it's way under the fenders -- if you ride in any water what-so-ever, it's a bad idea. More debris will also enter a open airbox.

My suggestion would be to open the box, back behind the filter using a similar setup to an HRC lid or by cutting a hole and installing a vent.

I'd also recommend using an outerwears on whatever filter you choose for the sand.

Also listen to Scottie's advice on cleaning and oiling the filter.

If running an outerwears, take care in trying to keep as much filter oil off the outerwears as possible - the outerwears will do it job better if the debris hits it and falls off instead of sticking to oil on it.

[sparky450AR]

Originally posted by 86atc250r
Don't fall into the trap of believing "more is always better".

Just like running without an exhaust system, opening the intake side completely may result in a power loss as well.

Although I haven't performed any testing on the 450R, on the 400EX, completely opening the lid actually resulted in a top end power loss (regardless of jetting) - believe it or not.

In my experience partially opening the airbox is the way to go - similar to the HRC lid or cutting a hole in the lid and installing a "vent".

Also completely opening the airbox lid exposes the filter element to anything that can find it's way under the fenders -- if you ride in any water what-so-ever, it's a bad idea. More debris will also enter a open airbox.

My suggestion would be to open the box, back behind the filter using a similar setup to an HRC lid or by cutting a hole and installing a vent.

I'd also recommend using an outerwears on whatever filter you choose for the sand.

Also listen to Scottie's advice on cleaning and oiling the filter.

If running an outerwears, take care in trying to keep as much filter oil off the outerwears as possible - the outerwears will do it job better if the debris hits it and falls off instead of sticking to oil on it.

I agree, the airbox lid partially opened, if your ever in water is the only way to go. As you can see in the picture below, it only exposes less than a quarter of the filter to falling water. When i cut my lid today i left lips on the outer part of where i cut it, to help shed water even more. I will also buy a filter outerwear, and probably run a UNI.

http://www.imagestation.com/picture/sraid122/p61c6713ba2dda610f3f64d1063ed54b4/f83cde49.jpg
http://www.imagestation.com/picture/sraid122/pb204d992c884afae0d5ff5d305909544/f83cde47.jpg



I went ahead and put a 182 in it today, and cut the airbox lid. It started up fine and reved out very good, but you can never really tell until you wind it out in fifth. We are going to the strip saturday, to jet it right. I will post final results

[roughrider01]

I have the HRC lid but took it off for a few rides to see if i gave it anymore power and i couldnt feel a difference at all. I couldnt believe how dirty my filter got without running the lid by only riding thru a little bit of mud. There were big globs of mud all over it, the HRC lid does a excellent job at creating good airflow and keeping the filter clean.

[trout]

Thanks for all the responses guys. I appreciate your time, I did order an outerwear for the airbox lid from NACS, so hopefully that is a good idea, im going to the dunes this weekend and will pop in a 180 main to start and see what happens.

Thanks

Trout