FREE HP with some simple mods

[mxpimp2000]

i just done some mods to my stock air box and intake tube. i cut the screen outta the stock cage and i drilled some 1/2 holes in the bottom and rear of the box to help with air flow.

dyno proven 3hp. also the reason for this is because the seat actually blocks air and hp on the dyno u can remove the seat and gain numbers. how ever put the seat on and its almost like puttin the lid back on it.

some ppl cut the whole rear outta the stock box but i decided to just drill holes.

since i done this mod my jettin has significantly changed and i will be changin my jettin and gettin the extra hp ive been missing

[quadboy-55]

very interesting you should post this. just this morning i was looking at my seat and how its killing flow, then i looked and didnt want to gut the battery box, and looked about on making holes, after cleanig my filter.

i think im going to try this aswell.

also, its in a low lying area, but remove the stock drain tube, water can drain, and more air flow.

[mxpimp2000]

ive never had the drain plug on my box as well. ill post some pics that ive found of the box mods.

also u can cut the extra plastic around the battery box that shrouds the air box in the rear portion.

this is a pic from a buddy his box dosent have a rear wall it was completely cut out

with the screen alone removed it helped 50% on air flow

[mxpimp2000]

PIC 1

YOU COULD CUT THE REAR OF THE BOX OUT LIKE SHOWN AND LEAVE THE PART I HAVE OUTLINED IN RED IF U WERE AFRAID OF WET AND MUDDY CONDITIONS. HOWEVER I RACE MX SO IM NOT WORRIED BOUT REMOVING THIS

[mxpimp2000]

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[mxpimp2000]

just found this K&N intake and im willing to bet its gotta be better than the FCI kit

[mxpimp2000]

web site: http://images.google.com/imgres?imgurl=http://www.knfilters.com/images/l/63-1123.jpg&imgrefurl=http://www.knfilters.com/news/news.aspx%3FID%3D2011&usg=__TSJkfVMCIAwgv0Hk2kHYVv_r49g=&h=514&w=750&sz=53&hl=en&start=9&um=1&tbnid=8eHedDbKfBlkRM:&tbnh=97&tbnw=141&prev=/images%3Fq%3Dyfz450%2Bair%2Bbox%26hl%3Den%26sa%3DN %26um%3D1

pic2

[mxpimp2000]

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[csr250r]

Do you have any pics of yours with the holes drilled?

[Pack]

Originally posted by mxpimp2000
just found this K&N intake and im willing to bet its gotta be better than the FCI kit
It should be better for double the price.

[mxpimp2000]

yea i couldnt find a price on the k&n site but now i see its almost 450 dollars lol

shows 4.72 hp gain. i guess u pay 100 per HP gain

[quadboy-55]

thats cool that K&N has a kit, but im not sure why its so much. and if it can clear an aftermarket shock. the FCI says it works will all aftermarket shocks. but i want to see how these both compare, and with the ron wood intake, as it looks almost identical to the K&N.

nice airbox trimming by the way. i think im going to do that.

[mxpimp2000]

Originally posted by csr250r
Do you have any pics of yours with the holes drilled?

heres my box

[mxpimp2000]

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[mxpimp2000]

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[mxpimp2000]

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[mxpimp2000]

i went ahead and cut it out

[quadboy-55]

still, for wet conditions i have an idea about adding a big hole and kindof a snorkel to the hole you didnt cut, where the tool bag normally goes. and then getting a tube that has a 180 degree effect for the drain tube to water isn't forced up. i'll need to get some pics to explain what im talking about.

[quadboy-55]

this is kinda what i was talking about, for the MX racer who wants to avoid the wet, or the XC racer. i feel it looks alot cleaner in my oppinion.

[quadboy-55]

i also edited one of the already posted pics to represent the intake mod, although there was a new airbox, i did my best to outline where the stock box should be for the mod.

[quadboy-55]

pic, *srry.

[mxpimp2000]

lol musta took 4ever to draw that up lol ill stick with my somewhat of a airbox i have left,

[Ride1Rob]

If you race or ride MX why not just get rid of the whole box?

[quadboy-55]

Mx pimp: i was just posting my two cents, i think im going to cut mine like how you did, and still cut the hole at the bottom like a breather.

Rob: an airbox keeps the elements out of the filter, so its cleaner, longer. the chain can swing left over oil into the filter, aswell as dust from the wheels.

BTW: i have a better design for the airbox mods, that i plan to exicute on my YFZ later on down the road, and hopefully pick up more power, and try to get air from the cleanest places so intervals can be lengthened and performance at its peak for the longest possible time.

haha, yea, it did take quite a while to draw.

[Ride1Rob]

If you're racing MX all you need to do is clean it from race to race or practice to practice. I've been running an airboxless intake for about 3yrs now. I normally clean my filter everyother ride and that speaks volumes here in Florida where it's hella dusty. Even with those holes drilled it's restricting the air intake and you're not getting optimum performance as opposed to an airboxless intake. If you're racing every bit of power increase helps.

[mxpimp2000]

Originally posted by Ride1Rob
If you're racing MX all you need to do is clean it from race to race or practice to practice. I've been running an airboxless intake for about 3yrs now. I normally clean my filter everyother ride and that speaks volumes here in Florida where it's hella dusty. Even with those holes drilled it's restricting the air intake and you're not getting optimum performance as opposed to an airboxless intake. If you're racing every bit of power increase helps.

i clean my filter every race/practice. it only gets raced or practiced i never just take it out on a trail ride or anything. since i drilled the holes my jettin has been thrown off some so now that ive cut the box almost out im sure the jetting is goin to be way off. it was lean on the pilot but ill prb change a size on main and pilot now

rob is a experienced guy knows alot about the yfz and has helped me out alot.

quadboy no offence taken on ur posts thats why i posted for more ppl to post the 2cents and wat they knw a trick or 2 that i dont know, keep the post coming

[Toadz400]

Rob does know his stuff. Quadboy does make a good point for people who aren't racers. The weekend warriors who would rather avoid cleaning the filter after every ride but still want that extra flow. An air box-less set up is obviously more ideal for racers where every little bit counts.

Good idea though quadboy. Keep on designing and start fabricating.

[mxpimp2000]

pics of new

[quadboy-55]

im not trying to bash anyones posts at all, and i believe rob knows his stuff. i ride mostly MX and if i had to compare it with the other riding i do i'd say almost 90%MX and 10% other. 70 foot jumps are well within my comfort zone.

my track and other tracks i ride are fairly dusty, and i end up cleaning my filter every ride anyway, so an airbox is ideal, so when i went up to design an new air inlet thats one of the first blue prints i made on page two. after that i thaught the hose was too much of a hassle and the hole was too small so it wasnt worth it. anyways. im finnished my air box trim after some careful planning and made it sealed off quite well from the elements. after testin im pleased to find out that its noticably lean even with the lid on, and dramatically lean with the lid off (it was origonally jetted for no lid) so thats a real plus. the inlet on the rear plastic/batt. box you can feel sucks alot of air through, so i'd call it a job well done. im going to start a how-to for this progect so everyone can follow along.

heres a pic of the finnished air box.

[quadboy-55]

link to full story.

http://www.exriders.com/vbb/showthread.php?s=&threadid=408546&perpage=13&pagenumber=1

[Ride1Rob]

I just don't want you guys taking all this time to modify these boxes and putting all the thought process into it when there's no need to. The moment you line up against a bike that has no restriction and is setup properly you may think back to this post. If you were racing Hare Scrambles or doing muddy trail rides or riding in somewhat watery conditions these modifications would be needed. But putting snorkels and such on an intake that's mostly MX ridden is overkill in my opinion. To ride a MX track in wet conditions is a waste of the day and if it's underwater the track shuts down.

To me it would just make more sense and less time and effort to get an aftermarket intake. Even with the holes drilled the stock intake is very restrictive. For one I see a foam airfilter on Pimps bike (Still minimizing airflow). Also, the stock intake boot slows the velocity of the air tremendously as well as restricting the amount of air going through the carb. I've modified a few of these boxes and the bike runs better due to alot less restriction. The only restriction then is the type of filter you have and the intake boot.

Just so you guys don't think I'm just babbling on if you'd like I'll post some vid of my bike in action. One of bike with the exact same mods as mine and another is of a bike with more mods.

[mxpimp2000]

Originally posted by quadboy-55
link to full story.

http://www.exriders.com/vbb/showthread.php?s=&threadid=408546&perpage=13&pagenumber=1

very well done :D :D

[csr250r]

I race Mx but they get the track so muddy then send quads out to practice first, If you ran no airbox your filter would prolly get plastered with mud.

[Ride1Rob]

If you have to deal with this quite a bit I'd look at what these guys are doing to their airboxes. I know here in Florida if it starts raining most MXers packup if the track is muddy. What I did on my stocker was modify it to seat in around the airfilter in case something like that happened. The airbox and the intake with the filter were 2 seperate peices. Even though I ride in the rain and through small puddles I never use it because I never ride in deep standing water.

[mxpimp2000]

they do the same here at local tracks but quads are usually the 4th practice out on the track. i usually run a site lap to see where the mud spots are and i walk the track also. im not gonna run my bike wide open in practice anyways. but like they say when playin cards. dont show ur hand until its time to throw down:D

my filter is exposed quite abit now that ive cut the hole rear outta it but still has the sides blocking it from my exhaust heat and such but i think it should help mine quiet abit from the lil mods i made

[quadboy-55]

i understand what rob here is getting at. sure that set-up alows for the most possible air flow, but a dirty filter becomes more restrictive, and the faster the filter gets dirty, the faster you loose performance. the goal i was trying to reach with my mod, and MXpimps mods, where trying to keep the filter cleaner, longer and still get notiably more air to the filter. i think i reached that goal with my mod, and im sure other ppl can agree with their own versions of a cut box.

im all for the FCI, and infact thats one of my next mods. i still plan to use my stock box with the extra inlet, for longer intervals and increased performance over a stock box.

im not trying to go against a no-box intake, it might work for you really well, but for me, not so much.

BTW: thanks for the comments about my air box mod! :D removing the screen is next until winter for the FCI.

[Ride1Rob]

A clogged filter will not only rob hp but will make the bike run like crap. Look at the video below and you'll see the conditions I ride in everytime I ride (Unless it rains the day of). After a ride like the one in the vid I'll clean my filter after that ride. On this day we were out there from 11am til about 4pm. My bike performed the same throughout the day in these very dusty conditions. I can see your point being an issue for someone's bike that's not jetted properly (Too rich).

This is a long vid so pause it and let it load til the end for no disruption in playtime. I'm on the silver/gray YFZ with the black/white/red riding gear. http://www.youtube.com/watch?v=AZR4rJxJIOs

[mxpimp2000]

Originally posted by Ride1Rob
A clogged filter can rob hp but that's only likely to happen if you're jetted pretty rich. Look at the video below and you'll see the conditions I ride in everytime I ride (Unless it rains the day of). After a ride like the one in the vid I'll clean my filter after that ride. On this day we were out there from 11am til about 4pm. My bike performed the same throughout the day in these very dusty conditions. This is a long vid so pause it and let it load til the end for no disruption in playtime. I'm on the silver/gray YFZ with the black/white/red riding gear. http://www.youtube.com/watch?v=AZR4rJxJIOs

kool vid rob. no offence but wheres the jumps lol everyones riding is diff just wanted to throw that at ya ill post one of my vids to show my ridin environment conditions. little extra at the end (not me)

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[Ride1Rob]

Originally posted by mxpimp2000
kool vid rob. no offence but wheres the jumps lol everyones riding is diff just wanted to throw that at ya ill post one of my vids to show my ridin environment conditions. little extra at the end (not me)


I got smart when I got hurt lol. Over jumped a double and flat landed. Don't know how I didn't tear my achilles. Tried to get back into it a couple months later after I healed up. I did a few laps and rode off the track and haven't been back on a mx track since. That was about 3yrs ago. My son races and he used to bug me about racing on his race nites. I had to explain to him the risks it involves when you have to go to work and take care of responsibilities (Wife and 3 kids). He understood when I said if I got hurt and couldn't work he wouldn't be able to race because I wouldn't be making any money lol.

[mxpimp2000]

Originally posted by Ride1Rob
I got smart when I got hurt lol. Over jumped a double and flat landed. Don't know how I didn't tear my achilles. Tried to get back into it a couple months later after I healed up. I did a few laps and rode off the track and haven't been back on a mx track since. That was about 3yrs ago. My son races and he used to bug me about racing on his race nites. I had to explain to him the risks it involves when you have to go to work and take care of responsibilities (Wife and 3 kids). He understood when I said if I got hurt and couldn't work he wouldn't be able to race because I wouldn't be making any money lol.

you sound like my dad only he dosent ride but thats what he tells me that i need to quit and all this and that and he cant ride because he has to worry bout payin his bills and being able to go to work the next day lol

[quadboy-55]

youre track seems really dusty. but u need jumps. LOL

heres mine, its not a very fast track, skip the beggining if you dont want to watch me and my buddy talk about a rut in the table top.

http://www.youtube.com/watch?v=ZiFK2bmK1bE

[Ride1Rob]

That's a nice track you guys have there. If we had something to make jumps like the ones you guys have that would be nice. I wouldn't mind riding something like that but here it's very sandy and the tracks beat you up pretty bad because of all the ruts and braking bumps.

[quadboy-55]

thanks, the biggest jumps is 74 feet, and only one corner is suffering bad from braking and especally accell bumps.

i used a bobcat and got dirt trucked in from new developments. if you dont tell them u r making a track they will pay you to dump.

[mxpimp2000]

Originally posted by quadboy-55
thanks, the biggest jumps is 74 feet, and only one corner is suffering bad from braking and especally accell bumps.

i used a bobcat and got dirt trucked in from new developments. if you dont tell them u r making a track they will pay you to dump.

i wish i knew how to get free dirt:confused:

[quadboy-55]

Originally posted by mxpimp2000
i wish i knew how to get free dirt:confused:

not only free, but they pay you to dump! make a track, and get cash doing it!

[Dansc90]

Whats a good intake so i can get rid of the box, and stock boot? Mainly the stock boot is what i want to get rid of. The track i race at they water it like crazy and send the quads out for first practice. And we race in any condition pretty much. Cant afford to loose an points. Its a very competative track.

[Ride1Rob]

Originally posted by Dansc90
Whats a good intake so i can get rid of the box, and stock boot? Mainly the stock boot is what i want to get rid of. The track i race at they water it like crazy and send the quads out for first practice. And we race in any condition pretty much. Cant afford to loose an points. Its a very competative track.

What type of dirt/sand is the track? Here they also water the tracks alot due to it being so hot and dusty. But they don't water them to the point where it's deep standing water on the track or mud.

There are a few aftermarket intakes you can get. ESR, FCI, Ron Woods, Velocity, and now the K&N. Just a matter of price.

[mxpimp2000]

Originally posted by Ride1Rob
What type of dirt/sand is the track? Here they also water the tracks alot due to it being so hot and dusty. But they don't water them to the point where it's deep standing water on the track or mud.

There are a few aftermarket intakes you can get. ESR, FCI, Ron Woods, Velocity, and now the K&N. Just a matter of price.

velocity is junk!! K&N,FCI,ron woods,ESR thats the order id put them in but its my opinion

[quadboy-55]

LOL, i've owned two sets of Velocity filters, one for a LT-Z 400, and one for an LT-R 450, both where horrible.

[mxpimp2000]

finished product

[mxpimp2000]

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[Dansc90]

Its up in northern Pa. Mapleshade Mx. Its just normal dirt, But on weeks that its rained all week it can get really nasty. I'll get some picks and post them.

[Dansc90]

Well the pic was to big to post, but if you go to www.brokenoaksphoto.com they take alot of really good pics of the track. There all from this year and we have had pretty good luck this year as far as rain goes, but if you look in the "Real Men Practice In The Rain" file, it will show you about how much rain we can get. It was just a practice day, so the track isnt taken care of, but it gives you an idea on how much rain we can get.

[quadboy-55]

LOL, i ve ridden one time like that, and i hated the time i had with the pressurewasher trying to get that off. not fun.

[mxpimp2000]

found this pic of a modded box

[quadboy-55]

i woulda kept the bottom to shield the filter atleast a bit. other wise it looks really good.

lateron i'd find a round clip that i can bolt onto the frame to make it look cleaner for the vent hose instead of a zip-tie tho.

[mxpimp2000]

idk why ppl put filters on those because it blows air out along with oil also..and also when u was it that filter can get wet and water can drain down tha hose and get into ur crank case:eek2: i run mine to the ground because it drips oil now and then but not always, just like the dirtbikes it runs to the ground both hoses

[quadboy-55]

just a piece of foam is good to keep forign objects to a minimum in there is a good idea.

im thinking about trimming more plastic from the bat. box area.

[brett#9]

pro design will open up your stock intake its the best bang for your buck then cut out the back of your box i have had mine like this for years no probs.