Modern Vespa

Hi Folks;

I'm planning on making a custom air intake hose so that I can retrofit a 3.5"rdx6" dual layer foam air filter onto an MP3 500 (this size should good since it exceeds the area of the OEM filter). I've seen the infamous Scarabeo 500 mod with the 2" turbo hose (http://apriliaforum.com/forums/showthread.php?t=173153), but the engines are not the same and I don't think that the routing of the hose will quite match his approach (although I'd LOVE to be proven wrong).

I'd like to get rid of the existing airbox that could not have possibly been designed by an Italian (read that as UGLY).

My question is for anyone who has their scoot apart (or may be working on it) - can someone measure and tell me what the outside diameter of the intake connection on the engine end is? I'd rather not start tearing mine apart until I'm ready, but I'm going to need that diameter so I can start tracking down a piece of hose to fit (or adapt to fit).

Any help would be appreciated.

Thanks!

Zang

Coley likes this. Keep us posted!

edit, I just went to take a look, but it had to be quick as it's just starting to rain here. I'd say 2" OD sounds about right, but possibly a bit larger.

The Scarabeo 500 has the 460cc engine and the MP3 500 has the 492cc engine. The MP3 has the same engine just bored out a little bigger and with 2 sparkers. The intake manifold should be the same on each.

Did you ever get your measurement? I assume you're talking about the OD of the throttle body. I, too, would like to remove the air box and replace it with something more elegant. And to the folks who shout "Too Lean! Too Lean!" I say the throttle body is what controls the amount of air into the engine. The airbox is just the source of that air.

But the ECU has set parameters and can only compensate so far. To much air and it's going to run lean.
People have tried this and it ran like shit.

But go for it, you may find the right combination.

Wayne B

Who are these "people"? Please! All you "people" that have tried this, please speak up!

Again, I say the throttle body is what controls the amount of air into the engine. The airbox is just the source of that air.

I used to have an Aprilia Atlantic 500. I modified the airbox on that scoot, and it made a significant difference. Do I have a dyno chart? No. But I know before the mod my brother and I would race with him on his KLR650, and he'd out run me easily. Once the airbox mod was done, it became A LOT closer.

Now back on topic, I found another post that said the throttle body diameter on a 500 is 1.625". Can anyone confirm that? And is that outer diameter?

You need to be careful - the EFI is only able to make very minor adjustments to mixture (the air:fuel ratio). Typically this is at minor throttle openings.

The increased airflow requires more fuel to be injected, especially at WOT. The inbuilt fuel map controls this, and I don't know that there is any way to easily modify it.

Lack of fuel leads to overheating and can cause a hole in the piston due to pre-ignition and the consequent erosion of the piston crown.

All the best

Trevor G

I agree with what you're saying. And maybe I said it wrong. I'll try again. The throttle body, along with the EFI/ECM electronics, control the amount of air going into the engine. The airbox is simply the source of that air.

No, the air box provides and designed amount of restriction.

Wayne B

what about these?
http://wiruswin.com/piaggio_mp3/sp_parts/aircleaner.html

Yeah...I saw those in another thread. What I didn't see were any design specs or USA availability.

And Wayne, I agree with you that the airbox is restrictive. But, in my opinion, that is a problem, not a feature. The butterfly in the throttle body should control the amount of air the bike uses, not the airbox. My opinion is the restriction provided by the airbox is more about reducing noise than air.

Once I find an acceptable solution, if I have a problem with the way it runs, I'll be the first to come here and admit I was wrong. But I haven't read or heard anyone that has tried something less restrictive complain that it was a problem for them. I have, however, read of someone riding at high elevations getting a check engine error due to lack of air. That tells me something. And heck, even the Athena air filter I'm using now made a positive difference.

Ray at higher elevations the air is NOT as dense as sea level that is why you have lack of air. As far as the mixture of fuel and air you do need the correct combination for the timing of the spark and the tempature of the spark plugs to properly burn ALL the fuel/air mixture properly. more air and less fuel will cause overheating and possibly piston /ring siezures. Too much fuel and less air will cause it to run "rich" and will foul plugs. If you follow any m/c racing circles the mechanics are always checking the fuel mixture on the comptures to get the proper ratio for the HP of what the engine was built to. You can change the air box configuration slightly and get some more preformance without too much risk. But you increase your risks with more drastic mods. It is your scoot and you do what pleases you . Have fun with the mods you choose.

Again, has anybody here tried it and had some of these disasterous results?

Now back on topic, I found another post that said the throttle body diameter on a 500 is 1.625". Can anyone confirm that? And is that outer diameter?

From the lack of responses to both questions, it seems I will be breaking new ground here. Not that it will be the first time.

I suspect that no-one is going to spend half-an-hour breaking their bike open to give you an answer you could get for yourself.

..and I would never expect anyone to do that! Please forgive me if that's how it sounded.

I thought maybe someone might have a shop manual with the data, or maybe someone had done the measurement prior, etc.

I have been running this setup for about 6 months and at least 1000 miles. I am VERY happy with it. There is a definite increase in power, a great growling sound, and the bike looks a ton better without the bulky airbox.

As with any intake or exhaust mod with an EFI controlled vehicle, reset the control box so that the computer will learn how to use the new air/fuel parameters most efficiently. This is done by disconnecting the battery for a few minutes (I do 15 just to be sure).

As a side note, I am also modifying a two brothers carbon fiber exhaust can off a cbr600 to fit the 500, I have just been lazy about welding up a reducing pipe from 2" to 1 &1/2.

hey hey hey after 6 months you inform us with the new air intake? now i really want to know where you bought that, can i just screw it on?
another question, the standard air intake has two tubes to dumpe oil in, how do you compensate this?

Yes, please do tell!! Also, are there other K&N filters that would work....I guess what I'm asking is is this the best one or just the first one you tried? Will it just clamp over the old pipe? Fill us in please...I'd love to get rid of the large fugly air cover...

I am no longer posting on this board about mods I do on my scooter. I am tired of certain members who think that Piaggio has designed the universe's most perfect scooter that cannot be improved upon mechanically. It seems every time I came here an asked a question I wag ragged upon saying that it can not be done and SHOULD NOT BE DONE!

I still like to read the forum daily, and love to come across threads with people who are genuinely inquisitive about what these machines can do... But I am tired of the conversations about what is the cutest helmet and the new threads about the same 5 mods that every one here had done.

There is an aprilia forum http://www.apriliaforum.com/forums/index.php that is run by the very knowledgable AF1 racing outfit here in Texas. I have been a member of for a year and a half and they take a serious and inquisitive approach to the mechanical and ergonomical side of bikes.

They have even started sections just for the MP3 classed by engine size but I dont think anyone knows about it yet.

One of our very respected MV members "88&stillriding" has moved over there now that he bought a Mana...

an extra forum doesnt hurt

Hmm...sounds like you have no problem screwing the people who enjoy your posts equally with those who argue with it...I personally don't like forums where everyone is "you're the greatest and your mods are perfect in every way". I've always enjoyed your contributions but if you feel more at home at a place where others don't question mods of any sort due to safety, mechanical, or design reasons, then don't complain when your scoot overheats, fails, or is ticketed for not being street legal. I'll miss your informed and somewhat adventurous mods on what may not be the perfect scooter but is definitely the best 3-wheeled scooter.

Hey mate, still waiting for the answers

i would appreciate if you could inform me, looking for this...

I dont remember the exact size, but take a pair of calipers and measure the outside diameter of your intake tube. Go to the K&N filter site and go to the universal filters section. They have various sizes and shapes. I liked the look of the conical one the best so I selected that one. Just make sure that the Inside Diameter (ID) is approximately the same size as the Outside Diameter (OD) of your intake tube. They come with a band clamp that will tighten it down after you slip it over.

thanks but what about the tube on the left which ussually tabs of exceed oil?

I most certainly do not want everyone to agree on everything nor have the same opinion and especially to think that I have the best mods in the world...

What I do want is people to be open minded and examine a topic before stating that is can not or should not be done even though they have no idea what they are talking about, and not the first inkling of the mechanical workings of an engine.

Either leave it open to drain, or you can do what I did and get an endline breather filter from your local auto parts store.

Scoot Man - Very good information! Thank you for taking the time and showing the courage to post it! While we may be the minority at this point, there are those of us here who feel the need to tinker with our toys. Real world experience gained through that tinkering, in my view, is worth its weight in gold when compared to speculation and hearsay. Please keep posting your mods and their results, both good and bad. I, for one, would never criticize anyone for being the first to try something new...unless, of course, there was solid evedince such an experiement would produce disasterous results.

scootman what is an an endline breather filter?

yes pics please!

Take a look here:

http://www.knfilters.com/vent.htm

Yes the first 4 are what Iam talking about, but you can get cheapies from an autoparts store for a couple bucks...

I think I might have to make some time to fabricate that exhaust adapter this weekend now that someone else than myself would be interested. I would really like to get some before and after DYNO time to compare the powerband curves and to see how it changes for the good or bad.....

With the improved exhaust (which I think is the inhibiting factor on the LV exhausts not making significant gains), the higher revs the JCosta is giving me, and the opened up exhaust I should see a definite improvement over stock.

I have been curiously following the Performance Clutch threads, but am a bit wary. It seems like it would be driving a performance car with a stall converter; like your always getting kicked in the but. It would be great for all out throttle or racing, but a bit much for daily driving.

I hope they can get the spring balance weights figured out to where it blends a good compromise of everyday drive ability with increased performance...

I am seriously considering going 88's route and buying a Mana, but at the same time I am thinking of tinkering with the 500's engine a little to see where I can take it.

I finally dug into the scoot to measure the outside diameter of intake port on the 500. It looks to be, according to my micrometer, 55mm, or @2.1875".

It has a slight lip on it, and the 55mm is the diameter of that lip.

I've ordered K&N filter part numbers RC-2330 and RC-1250 to see which one will fit best. I've also ordered the pre-filter to help resist water penetration. Those are part numbers 22-8028 and 22-8029 respectively. At the same time, I ordered the crankcase vent filter 62-1030. I'll be looking for a piece of 3/4" ID hose, probably auto-type water pump hose, to help hold that vent filter above crankcase level.

I'll post results and pics(maybe) when I'm done.

Ray R: still not done?

OAD, I read in other threads that you have a K&N, what changed your mind?

miles and plugs checks changed my mind. I kept checking my plugs and they kept getting darker and darker. A over rich indication. and doing some more learning on the throttle body ECU. I decided to try increasing the airflow in to get the plugs to a leaner color and I didn't want to cut and modify the airbox itself so I took a plunge and went with the K&N. This also stopped the backflow/spray of crank case oil into the airbox that kept filling that tube in the front of the CVT cases. (pain in the ass to drain all the time because i ride pretty full throttle) So hope that helps you some.

Thanks, did you use the hose breather filter located vertically higher to reduce the oil escaping the crankcase?
I have a similar oil amount as you describe, maybe it's just a symptom of the throttle behaving like an ON switch

yes I did zip tie it up some on the breather vent line. I also rotated the air intake tube so I could plave the filter in a higher position up then used some zip ties to hold it there.

Sounds good, I'll do the same.
I missed out on the AEM filter I was chasing, but am taking a chance on a WirusWin style carbon chamber with pod filter inside, solves my "no hugger" intermediate time problem, and I can fit an exposed pod filter later for comparison.

I also found a cool Go Kart racing standard that uses a 67mm ID elbow fitting to a foam filter, and they have a road element, and an offroad/dirt racing (finer) element. There is also a standard airbox that fits over it, with two intake "blow holes" that kills the sound.
There is also a rain cover available to fit those two intake holes, like a muscle car bonnet scoop facing backwards

Not the path I've taken, but similarly workable.




Here's the rain cover


That bunch of kart gear looks like it would be an easy system to run without airbox in the dry, then slip airbox on for the winter/mud, run it upside down so you slice out the intake to be a downward intake but much greater area. Factory airbox benefits protects from rain and no need for a drain hole.

I have been racking my pea-brain trying to think what would work to muffle the sound a bit. Can you provide links to these items??? Thanks!!
Needs to be painted black. but seems ready to go otherwise.

They are on ebay, but the cheapest I've found for the airbox was just now by accident with google
http://www.kartbay.com.au/p/345182/air-filter-for-aka43-control-airbox-.html
http://www.kartbay.com.au/p/345180/gairbox-aka43-control-airbox.html

The yellow filter is the finer element dirt filter, for the fine dust of dirt racing.

Blue is coarser element for the tarmac.
I figure there is an excess of surface/volume there, I would probably opt for the dirt element, but I would probably buy the blue one as well as a quick swap over for fair weather testing

<$30 for filter, $47 for the airbox (on ebay all were $70), Australian dollars plus freight to USA probably be a cool U$100 on your door step Or at least a good start to finding your own karting standards if they have anything similar.

I'm not into karts (yet), just stumbled on this. Those dirt karts images sure does make me want to have a dirt kart. Or a 2-stroke kart for the tarmac