Bell-mouth intake
Post Reply    Forum -> Not-So-Modern Previous12345Next
Author Message
Mr. Clean
P,SUPER,V90, 50 Special
Joined: 27 Jul 2010
Posts: 10207
Location: This is't my locker!
Mon Sep 19, 2016 4:15 pm quote
oopsclunkthud wrote:
But as long as we are thinking in those lines, A short idle adjust screw with a hex head line a set screw and a nylon nonslip insert on the threads could do the job.
yeah.. I think we're thinking along the same lines.. Your description sounds like a good thing.. keep the flow as un-disturbed as possible..

... nice design work Patrick.
Hooked
Some Vespa, some Yamaha, some Suzuki...
Joined: 12 Nov 2014
Posts: 169
Location: Hamilton, Ontario
Mon Sep 19, 2016 4:22 pm quote
Got the bell today (20/20), this plastic seems brittle and is giving me anxiety... I don't like that there isn't enough room to insert a metal sleeve so that bolts aren't putting pressure on the plastic. I work on motorcycles and see this kinda stuff crack all the time if there is a bit too much pressure against plastic. Going to install tomorrow and see how it works out.
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Mon Sep 19, 2016 6:10 pm quote
understand the caution, but ran the following on a bike in cannonball and not only did it hold up coast to coast but is still fine 4 years later.



I have cracked thin (1mm) pieces that were in tension but never had an issue in compression. That said, some blue locktite on the screws and don't over tighten, oh and luck, lots of luck.
Mr. Clean
P,SUPER,V90, 50 Special
Joined: 27 Jul 2010
Posts: 10207
Location: This is't my locker!
Mon Sep 19, 2016 7:04 pm quote
that looks great.. what the red "gasket" on the back/right side made of?
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Tue Sep 20, 2016 6:08 am quote
Here's a shot of the first filter in place.

IMG_1502.png

Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Tue Sep 20, 2016 6:12 am quote
Vader19 wrote:
that looks great.. what the red "gasket" on the back/right side made of?
the "gasket" on that GTS bell is silicone tubing. ordered it from some fast and furious type place. better shots of it here:

GTS Tuned Intake
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: 6500
Location: Victoria, Australia
Tue Sep 20, 2016 1:55 pm quote
Looks great Patrick! Be nice to get some air blowing up under there to see what it does... tricky to hold it in place while you do that though.
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Wed Sep 21, 2016 5:05 am quote
Tha's a really good idea, need to come up with a way to dial in a flow rate. 200cc with perfect flow would be ~12L/Min (.5cfm) so allowing for gulpyness in the flow, if it does not budge at twice that all should be well.

I got a quote for the laser cutting. will have 5 filters by the end of the week.
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Wed Sep 21, 2016 5:53 am quote
oopsclunkthud wrote:
need to come up with a way to dial in a flow rate
Ouch, flowmeters can get expensive!
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: 6500
Location: Victoria, Australia
Wed Sep 21, 2016 6:48 pm quote
http://www.musclecardiy.com/cylinder-heads/build-flow-bench-port-flow-testing-cylinder-heads-part-3/

This looks do-able. Maybe the figures it would give might not be the same as a commercial unit but it would give you a comparison. I'd imagine you attach the vacuum cleaner directly to the bottom of the carb box using pvc plumbing bits.
Addicted
'76 Vespa Rally 200
Joined: 13 Feb 2011
Posts: 503
Location: Melbourne
Thu Sep 22, 2016 8:15 pm quote
oopsclunkthud wrote:
Looking for someone that can laser cut the foam. me with an x-acto knife is not doing a great job, but ok for the first one.

I'm still kicking the idea around of turning this into a product, but if you want to make your own here's a PDF of the outline.
I have a friend in the East bay who can laser cut. Let me know if you want to talk to him.
Ossessionato
2 matching N.Z. '69 VBC Super, 177cc Racer, VespaCross Bodge, Puch SRA150, Piaggio Zip 100! & others
Joined: 26 May 2013
Posts: 3695
Location: Millbin, Ostrayleea, mate
Thu Sep 22, 2016 10:47 pm quote
if the RED filter is the Malossi with grey/red, then you have it upside dows, as the RED is the coarse & grey is secondary fine filtration.
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Fri Sep 23, 2016 6:48 am quote
SubEtherBASS wrote:
if the RED filter is the Malossi with grey/red, then you have it upside dows, as the RED is the coarse & grey is secondary fine filtration.
It's UNI 40 PPI Red coarse foam, I've had 5 cut (you can get 6 from a single sheet). May try UNI 40/60 PPI Dual Layer in the next round. but figured that the 40 PPI was finer than the stock filter.

If anyone wants to try the filter, I'll have 4 up for grabs. Drop me a PM.
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Mon Sep 26, 2016 3:40 pm quote
Got the first one done.

IMG_1523.png

Enthusiast
Rally 180, TS 125, PX 150 and a lot of smallies
Joined: 19 Oct 2013
Posts: 77
Location: Paso
Mon Sep 26, 2016 6:42 pm quote
I like the way that looks.
Hooked
Some Vespa, some Yamaha, some Suzuki...
Joined: 12 Nov 2014
Posts: 169
Location: Hamilton, Ontario
Fri Sep 30, 2016 6:22 pm quote
On some of my Japanese two strokes the spit-back from the carb is atrocious, easily 12 inches toward the rear wheel. I wonder what downside there is to having a bell mouth so close to the lid with so little space between the two.

I haven't had much time on my px150 since installing the bellmouth, but I noticed very little fuel on the lid or inside the air box. I was anticipating a huge mess in there without the filter.
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Fri Sep 30, 2016 6:31 pm quote
per "the article" the spit back is reduced with a well shaped bell.
Hooked
Some Vespa, some Yamaha, some Suzuki...
Joined: 12 Nov 2014
Posts: 169
Location: Hamilton, Ontario
Fri Sep 30, 2016 6:51 pm quote
Like most North Americans I don't actually read articles past the catchy headline, but I did notice very little spit-back related mess in the air box.
Ossessionato
1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
Joined: 26 Sep 2013
Posts: 4253
Location: So Cal
Sat Oct 01, 2016 9:43 am quote
PMF: What main jet are you using with the 20/20 bell mouth?
Hooked
Some Vespa, some Yamaha, some Suzuki...
Joined: 12 Nov 2014
Posts: 169
Location: Hamilton, Ontario
Sat Oct 01, 2016 2:46 pm quote
Starting point was

50/120
102/BE3/160

and so far it is

50/160
108/BE3/160

The 108 is a bit lean so I need to order a 110 and 112. I have a feeling that 112 is going to be ideal.

The engine is a ported stock 150 with 1.2mm squish clearance, cut back mazz crank, SIP road exhaust and case inlet was blended to carb box for 24/24 carb if I decide to use it later on. Jetting with drilled filter was perfect. I only got one day with bell intake. Cold weather and days of rain have put the Vespa on hold for now.
Mr. Clean
P,SUPER,V90, 50 Special
Joined: 27 Jul 2010
Posts: 10207
Location: This is't my locker!
Sun Oct 02, 2016 12:48 pm quote
I don't know if it'd fit under your panel Patrick.. but I'd be interested (you're much smarter than I am) to fab some kind of carb box top that had a "bump", "bulge", "slight dome" to the top to put a little space between the top of your nice stack and the inside top of the carb top box... I'm not sure what kind of clearance you have between the two now though.. so you may have it sorted already...

I've even been envisioning a carb box top with a cutout for the stack.. then you could put another filter over that).. You've done such a nice job, I'd just like to see it breath....
Hooked
Vespa PX200
Joined: 27 Jun 2010
Posts: 346
Location: Belgrade
Sat Dec 10, 2016 9:22 am quote
Hey so -- sorry to butt in like this, but I'm really really curious to know how this air filter approach turned out.

I've got the polini filter installed, and it makes the engine a fair deal louder, and it also irks me how installing one of those exterior filters forces you to ditch the bellow and the relatively clean and cool air coming down it. Oopsclunkthud's solution lets you keep it.

One thing that gives me the heebie-jeebies though is the idea of gluing this filter to the rubber gasket. I wonder if it could be more securely mounted to something like that DRT air box spacer. Would make for easier removal and cleaning as well.

How is it turning out performance-wise, though?
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Sun Dec 11, 2016 8:42 pm quote
I just got my garage space back so I'll be moving forward on this again soon.
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Fri Mar 10, 2017 3:31 pm quote
good news, the filter does not budge bulge or anything even at WOT and high revs.

There is some spitback with the bell at low revs and WOT but no other times.

IMG_1725.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: 6500
Location: Victoria, Australia
Fri Mar 10, 2017 5:34 pm quote
The cover looks a lot cleaner than I would have thought.

How much clearance is there between the cover and the bellmouth?
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Fri Mar 10, 2017 10:14 pm quote
there's not as much room between the bell and the cover as I expected, but I think the clear sits a bit lower.

I do think it has enough clearance, but I've got some smoke on order to look at how things flow.

IMG_1723.png

Addicted
2012 Stella 4T
Joined: 11 Jun 2014
Posts: 903
Location: Twin Cities, MN
Fri Mar 10, 2017 11:24 pm quote
What a great solution, both the bellmouth and filter. I'll definitely be buying one once I buy a P.

I wonder if one of those heated wire polystyrene cutters can cut filter foam? Might give better results than using an Exacto knife or razor blade.
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: 6500
Location: Victoria, Australia
Sat Mar 11, 2017 12:02 am quote
oopsclunkthud wrote:
...I've got some smoke on order...
Do they charge by weight?
Ossessionato
1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
Joined: 26 Sep 2013
Posts: 4253
Location: So Cal
Sat Mar 11, 2017 7:06 am quote
Don't forget the rubber plug around the idle screw
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Sat Mar 11, 2017 7:29 am quote
SoCalGuy wrote:
Don't forget the rubber plug around the idle screw
been thinking about how to deal with that as the tophat can't rest on top of the filter anymore. have a few ideas.
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Tue Mar 14, 2017 4:34 pm quote
The smoke pen came today and, well, it's not really up to the task except at idle.

The filter does smooth the airflow enough that you get nice smooth laminar flow at idle and even really low partial throttle. Beyond that and it goes turbulent or the smoke is spread too thin to see.

The one big thing that it did show was that the idle adjuster creates a huge amount of turbulence and must be eliminated at any cost!
Ossessionato
1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
Joined: 26 Sep 2013
Posts: 4253
Location: So Cal
Tue Mar 14, 2017 5:48 pm quote
Get a fog machine. It can do double duty as a fun prop at your next party.

http://www.frys.com/product/8259006?source=google&gclid=COfnyICy19ICFQtofgodIfALUw
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: 6500
Location: Victoria, Australia
Tue Mar 14, 2017 6:02 pm quote
How about adding a shape around the idle screw to help flow? Like this below... it would be part of the bellmouth and go to the full height to the cover.

Other than that, it's possible (but maybe less accurate?) that you could adjust the idle using the cable adjuster on the outside of the box. If you were able to make a knurled knob that fits firmly to the hex on the threaded adjuster it would make this an easier job. You might avoid needing the lock nut by fitting a spring instead.

Clipboard01.jpg

Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Tue Mar 14, 2017 6:35 pm quote
The pointy end of the airfoil would need to go toward the bore of the carb but on the 24mm it's already so close that it bumps out a bit.

I'm thinking of cutting off an idle adjustment screw and slotting the end of it. Could put a nylon insert along the threads to keep it from turning.

Other option would be an adjuster built into the cap over the slide, but that would be a pain to adjust.
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: 6500
Location: Victoria, Australia
Tue Mar 14, 2017 9:04 pm quote
What about simply turning down the shaft of the idle screw?
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Tue Mar 14, 2017 9:21 pm quote
The spring adds to the bulk of it all, but also the spring is currently what holds the bell in place. I figured out how to create a cut down idle screw that will be able to be adjusted with a small screwdriver, but that will require rethinking how it's all held in place without adding more bumps to the airflow. May not be worth it.

I've got jets on the way, so soon we will see what kind of upjet is needed
Ossessionato
1964 GS 160 MK II, 1967 Vespa GT, 1968 SS180, 1964 Vespa GL, 1964 Vespa VBB, 2006 Buddy 125, 2013 BMW C650GT
Joined: 07 Apr 2008
Posts: 2890
Location: Boca Raton, Florida
Wed Mar 15, 2017 9:27 am quote
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: 6500
Location: Victoria, Australia
Wed Mar 15, 2017 1:23 pm quote
If the idle was external, then the bellmouth could be held down by a regular screw.
Banned
2:6
Joined: 11 Jan 2007
Posts: 7341
Location: San Francisco
Sat Apr 08, 2017 6:14 am quote
on the 24G is the top surface of the intake at the same level as the top of the float chamber? If it is then replacement float chamber top could be made that has the bell built into it. kind of like the top of the GS/SS carb.

This could also be setup to take a replaceable float needle seat.

b2aa1764-5228-46f6-998e-3447a81eed84.jpg

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: 6500
Location: Victoria, Australia
Sat Apr 08, 2017 5:08 pm quote
Looking at this I'd say a definite no. But how much more difficult does a step make the manufacture?
I like your replaceable seat idea.

Team Scooter Trash for Petfinder Foundation   Vespa Wasp Pin Badges   Yelcome Leather Top Cases and Roll Bags for Piaggio Vespa PX LX LXV GTS GTV
Post Reply    Forum -> Not-So-Modern Previous12345Next
[ Time: 0.6057s ][ Queries: 25 (0.1127s) ][ Debug on ]