Bell-mouth intake
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Sat Apr 08, 2017 8:27 pm quote
It' not hard to machine in a step, but then you also have the manufacturing variability of the carb. If it was the same level then flat is flat. Looks like only a mm or 2 max, I may order one and see if I can mill it down.

I can't take credit for the replaceable seat idea, was mentioned in another thread around here. Shocked it's still not been done.
Hooked
Vespa PX200
Joined: 27 Jun 2010
Posts: 346
Location: Belgrade
Sun May 21, 2017 1:20 pm quote
Just bumping this thread up again, on the subject of alternate ways to have a bellmouth intake on the carb *and* have air filtration *and* keep the air bellow. Bonus points for simplicity, and ease of cleaning.

Here's what I've come up with -- see attached.

See, I found a bunch of filters for old velocity stacks that might just snap on to the PX air box. (57-58mm diameter or thereabouts.) Then, so goes my thinking, the air bellow could be stretched over top of that, and bob's your uncle.

http://www.carburetion.com/Products/ProductDetails.aspx?part=CUSF57LP

http://www.mikunioz.com/shop/velocity-stack-with-gauze-fits-carburetor-spigot-58mm-thru-62mm/

https://www.merlinmotorsport.co.uk/p/weber-40-dcoe-mesh-ram-pipe-filters-pair-afm4056

http://www.bisonmotorsports.com/Push-In-Microphone-Filter-for-Bison-Motorsports-Ve-p/00-0057.htm

Whaddya think?

filtration.png

Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 6499
Location: Victoria, Australia
Mon May 22, 2017 2:44 pm quote
I have plenty of trouble getting the bellows over the carb box lip as it is (unless I do that end first, and then the trouble is at the other end!) so I'm not sure how well that would work... it could be fitted inside the hole (50mm diameter). But you still end up with a kind of non-filtering filter...

I like what a friend did on his. Just needs some kind of plate to keep it in place (2nd pic) - and a good tank removal/replacement technique!

David filter 1.jpg

David filter 2.jpg

Hooked
Vespa PX200
Joined: 27 Jun 2010
Posts: 346
Location: Belgrade
Mon May 22, 2017 11:35 pm quote
@ginch -- yeah, I saw that one, and it's ingenious, but it looks like a bitch to clean (as you point out.) I wouldn't want to have to pull the tank every time.

"But you still end up with a kind of non-filtering filter... " -- what do you mean? A few of of these filters have a *lot* of mesh to them. More than what's on the stock air filter, at any rate.
Molto Verboso
1979 P150X, 1983 P200E, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
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Location: Veria, Greece
Mon May 22, 2017 11:40 pm quote
Have you seen the "Dumbo" from MRP??

https://www.mrp-racing.de/Air-hose-adapter-50mm-DUMBO-Vespa-PX-T5-Sprint-Rally-VNB
Hooked
Vespa PX200
Joined: 27 Jun 2010
Posts: 346
Location: Belgrade
Mon May 22, 2017 11:52 pm quote
I haven't, but that's fascinating.

What does it achieve, other than allowing other air bellows to be clamped to the frame?

Maybe an inline filter could be installed on the end of it? Given the different clamping mechanism that would get around the trickiness of squeezing the stock air bellow over it.

EDIT: I see now that this Jumbo doodad was in answer to Ginch's question about having a secure mount for that polini foam filter mounted on the inside of the frame.
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 6499
Location: Victoria, Australia
Tue May 23, 2017 2:08 am quote
That Dumbo thing is a bit strange... looks like too much hardware for the issue at hand.
I wonder if you could find or make a conical-shaped foam filter that clips in to the body hole from outside?
Molto Verboso
1979 P150X, 1983 P200E, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 1183
Location: Veria, Greece
Tue May 23, 2017 2:41 am quote
I think a flat foam filter between the 2 plates would do the trick and it would be easy to clean...
Banned
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Tue May 23, 2017 4:56 am quote
I considered fitting a filter at the opening under the seat, still think that could be a good idea.
Hooked
Vespa PX200
Joined: 27 Jun 2010
Posts: 346
Location: Belgrade
Tue May 23, 2017 5:42 am quote
@oopsclunkthud -- me too. I bought that LML filter that goes in the hole there, but it looks very restrictive. And I've heard from more than one person that that's the case. The other thing that's worrying about relying on the underseat filter is that there are some holes elsewhere in the frame where dust and crap can sneak in, specifically the slots for the sidepanel latches.

Got a question here about the flow of air however, if I do try putting a filter at the opening of the airbox. Considering the whole point of this exercise is to maximize the efficiency of the bellmouth intake on the carb, would it not make sense to put the filtration as far from the business end as possible (i.e. in the frame)? Or am I thinking too much?
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Tue May 23, 2017 5:59 pm quote
JimVanMorrissey wrote:
would it not make sense to put the filtration as far from the business end as possible (i.e. in the frame)?
Yup, the further it is away the larger the plenum volume, but the more opportunity for other dirt to find its way in. That's where I was trying to get a good balance with the filter at the gasket layer of the air box. also considered a tapered cone shape filter inside the bellows.
Hooked
Vespa P200, Primavera 130, VNA200, Italjet Pack-a-Way Moped, Ciao etc
Joined: 24 Oct 2014
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Location: Humboldt County, California
Sun Apr 15, 2018 5:17 pm quote
Patrick...STL File?
Patrick,

Any chance you have an STL file of the 24 velocity stack I could try out? I'm at my brothers house with a 3D printer.

I don't remember if this is a business for you. If it is, sorry for the ask.

Dave Reed
Slugrockets SC
Addicted
1966 SS180,1968 Sprint, 72' Rally ,74 V90, '64 GL 150 & too many projects!
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Location: seattle, wa
Sun Apr 15, 2018 11:01 pm quote
Unless you are driving on dirt - don't you think the air coming from the frame is relatively clean ? DO you think a filter is really necessary ? I dont bother on one scoot and seems find over a year later...

I think any particle that could really cause damage is too heavy to make it into the carb. In all the twists and turns on the way there it will precipitate out. The light fluffy stuff that makes it just get s incinerated. I have NOT seen any evidence of much (any at all really ) dirt making it there in the hose near the carb.
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Mon Apr 16, 2018 6:18 am quote
Re: Patrick...STL File?
email sent regarding the stl file.

I ran the filter in addition to the stock filter last year on the Melee and took the bike on several dirt roads. I did see a good bit of dust from the back of the carb box where I didn't have the rubber plug over the idle mix screw. Saw no evidence of dirt making its way through the frame to the air box.

The filter is still not a bad idea but not convinced it's really needed.
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Thu Dec 06, 2018 9:29 am quote
another alternative for the 19mm

Screen Shot 2018-12-06 at 09.26.55 .png

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