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Post by lobarrett on Jun 29, 2014 18:35:42 GMT -5
Introduction
This thread will address the components and issues that make up my scooters Fuel/Air/Oil Components. All of this is part of my 50cc Vespa/Piaggio ET-2 Build Project that is underway.
FUEL
Engine to Carburetor - Original
The following photograph is of the Reed Valve Assemble, Intake Manifold, and the 12mm Weber Carburetor that was originally installed on my ET-2.
For the most part removing the components was a simple task. However, the intake manifold was held in by a factory installed headless bolt, so it had to be chiseled loose. Once loosened, the headless bolt backed out easily.
This was the first time the reed valve assemble had been pulled from the scooter. And, with 14 years/5000 miles of service on them, they seemed to be in remarkable good condition. However, they were showing signs of ware and were getting a little chipped along the edges, but there were no cracks or any noticeable distortion or damage. And, the reeds pasted the light test.
I had purchased a Top Performance V-FORCE3 reed valve assemble to replace the original, but I am now being advised that the FORCE3 set may not work very well in my configuration - so having a backup set might be a good thing. The Malossi 70cc Cylinder kit came with a set of Malossi carbon reeds that should fit the original block, so if the FORCE3 does not workout I will have a work around. As it stands right now, I will not be using the Malossi 70cc BBK in this build. This build will use a Stage6 70cc Sport Pro kit. Maybe the Stage6 kit will be a better match for the FORCE3 reed valves.
I have also heard that using reed valves that utilize metal crimp/stopping plates is not a good idea. If they fall off the metal plates can cause damage to the engine. As shown in the photo, the original blocks used metal plates and it has done so for 14 years with out a problem, so I don’t know if this warning is very realistic.
The thing I was amazed about was the miss-matching of the intake manifold base to the reed valve base. The hole in the base of the stock reed valve assembly was much larger (646 sq-mm) then the hole in the original intake manifold (153 sq-mm). It seems like this would drastically restrict the performance of my 50cc ET-2 engine. Of course, reducing the performance of the scooter was a design/sales goal of Piaggio.
Engine to Carburetor - Upgrade
The following photograph is of the Top Performance Reed Valve Assemble, Malossi Intake Manifold, and the 17.5mm Dellorto Carburetor that will be installed on my ET-2.
The Top Performance reed valve is all plastic – no metal parts. It also utilizes 8-carbon reeds where-as the original used 4-carbon reeds.
One of the interesting things with the TP reeds, are the small pin holes. Each reed has about 160 pin holes for a total 1260 holes for all 8 reeds. And, yes light does shine through.
Seems like, tuning the engine/carburetor for the “STREET” utilizing the FORCE3 reeds is going to be a real challenge – if you don’t get it right, hard starting and erratic idling are going to be the norm. Also, it seems like the holes would cause crankcase pressure issues that would make tuning even more difficult.
However, at $125.00 cost it is going to be hard not to try it out. A possible back out plan could be to use the set of Malossi reeds (no holes) that I have for one half of the TR valve assembly. Buy an additional set for the other half. If I have issues with the TR reeds change them out with the Malossi reeds using the TP block.
At least using the TP valve assembly with the Malossi reeds would eliminate the metal clamp/stopper plates used in the original valve assembly.
Another interesting thing is that the hole in the TR reed valve base (557 sq-mm) is an exact match to the hole in the Malossi intake manifold base (557 sq-mm). Turbulence of the fuel/air/oil mixture flowing through the intake manifold and reed valves should be dramatically reduced. This should be a good thing.
My knowledge base on the above stuff is very limited and it is almost none existent when it comes to carburetors. The above photo gives some dimensional information on the original 12mm Weber. The following photo gives the same dimensional information on the 17.5mm Dellorto Carburetor I bought to replace the Weber. It was originally purchased for use with my Malossi 70cc Sports Cylinder and the Tecnigas NEXT-R exhaust. Since than, I have bought a Stage6 70cc Street Pro Cylinder. My plan is to use the Stage6 BBK in this build and save the Malossi for a later project. So, my 17.5mm Dellorto may need upgrading to a 19mm or more.
For now, I will plan on utilizing the 17.5mm carb in this build – unless a better understanding is soon gained.
Like I said earlier, I really am lost when it comes to carburetors. From what I have been told, the Dellorto is much easier to setup/adjust then a Weber – which is a good thing for me. Dimensionally they seem to be close. However, the 17.5mm Dellorto internal throat is about 2.5 times greater then the Weber. Which I guess stands for more through put of fuel/air/oil and better performance if matched to the BBK and exhaust. That is assuming you can get more air to the carb.
A dramatic increase in the amount of air is one of my unresolved concerns. The engineers at Vespa/Piaggio did some strange things with their design of an air delivery system. I will post more about this later.
More Carburetor Information
I created the following worksheet to help me gain some insight into how my off-the-shelf 17.5mm Dellorto Carburetor was configured. Hopefully, I can use it when it comes to re-jetting, etc. I want to purchase a range of jets that can be used to tune in the carburetor once everything is running – this worksheet gives me the starting point.
One concern is the Weber has a bowl overflow tube – the Dellorto does not. Not sure if this is a problem.
This carburetor is basically a 17.5mm Dellorto carburetor packaged and sold by Malossi. I think all Malossi did was remove the original documentation that came with the carb and package it back up without any documentation under their trade name. Doing so would bring the Dellorto/Malossi product in line with the rest of Malossi not so user-friendly products.
However, I have heard that they actually re-jet the carb for better performance.
Basically the carb
Carburettor DELL`ORTO PHVA-ED 17.5 mm #1012 for automatic choke
main jet 5mm X 65,
idle mixture jet 34,
A7 needle jet (needle circlip third grove down from top).
17.mm Malossi/Dellorto PHVA Carburetor Worksheet
Just found a directory built by Brentof some of the article posted - 49ccscoot.proboards.com/thread/1234/directory-find-faster
Under “LINKS” found some info.
Motorcycle Carburetor Theory 101
www.motorcyclecarbs.com/carbs101.pdf
The link to: Lots of DellOrto Carburetor Info
www.thisoldtractor.com/gtbender/dellorto.htm
WAS BROKE so not sure what they had
Question/Concerns:
1) Guess my main concern deals with the size of the Dellorto – is a 17.5 mm carburetor going to be a good starting point or should I go UP.
2) If the 17.5 is OK – What range of jetting should I have on hand? And is it the main jet that will most likely be the only one that will need a change out?
3) If the 17.5 mm OK – Is the Force3 Reed Valve too much for it?
4) Would intake Porting be worth looking into? And, how do I tell if I need to do it.
5) The Weber has a bowl overflow – the Dellorto does not. Is this something I need to address?
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Post by 2TDave on Jun 29, 2014 19:05:07 GMT -5
Nice selection of parts. You can absolutely run that bbk with the carb you have. I run a del 19 with vforce3 and a Stage 6 sport pro mkii. The reeds have been excellent for my setup when it came to throttle response. I'd get a jet kit for tuning. If your using the stock air box you may need somewhere in the 75 to 85 range but that is a guess. I haven't worked with a 17.5 but it is doable. Guys race in classes limited to 17mm carbs in Europe. Since you are splitting the cases it would be a good idea to read up on matching the cases to the cylinder. Again I don't know about your particular cases but the minarelli's like some work done. I've got a set on the bench that I just split and was surprised at how off the fitting was from side to side. At the same time I'm excited to see the results of getting them smoothed up and flowing as I know the cases in my scooter now are the same and it runs strong with the set up I mentioned. The carb isn't to difficult at all. At least the phbg hasn't been for me. Just read up in the tech section and ask. That's gotten me through issues. I was struggling with my carb at the beginning and we couldn't figure it out. I posted a pic and Oldgeek looks and says dude you have your vents capped. Yep. I thought they were vacuum ports. Lol.
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Post by lobarrett on Jun 30, 2014 17:46:41 GMT -5
Nice selection of parts. You can absolutely run that bbk with the carb you have. I run a del 19 with vforce3 and a Stage 6 sport pro mkii. The reeds have been excellent for my setup when it came to throttle response. I'd get a jet kit for tuning. If your using the stock air box you may need somewhere in the 75 to 85 range but that is a guess. I haven't worked with a 17.5 but it is doable. Guys race in classes limited to 17mm carbs in Europe. Since you are splitting the cases it would be a good idea to read up on matching the cases to the cylinder. Again I don't know about your particular cases but the minarelli's like some work done. I've got a set on the bench that I just split and was surprised at how off the fitting was from side to side. At the same time I'm excited to see the results of getting them smoothed up and flowing as I know the cases in my scooter now are the same and it runs strong with the set up I mentioned. The carb isn't to difficult at all. At least the phbg hasn't been for me. Just read up in the tech section and ask. That's gotten me through issues. I was struggling with my carb at the beginning and we couldn't figure it out. I posted a pic and Oldguy looks and says dude you have your vents capped. Yep. I thought they were vacuum ports. Lol. Thanks for the reply. Air Box I thought early on – that I wanted on of those cool & colorful air boxes I have seen on some of the engines. But, based on a lot of the POST on 49ccScoot I decided to stay with the original Air Box. Now, I am having second thoughts…………… I will POST why later. Case Matching I would really like to do this and I guess it would be a good time. Just don’t know it I can – looks like a good place to screw things up. But I will and have been looking into it. Typically Brent will have a POST that will guide you through step by step, like the one he has on fitting crankcase bearings. But, not with the case matching his video on it makes it look like a real tough thing to do. So I might just have to wait until he does a less frightening looking Video. dude you have your vents capped I saw that – it one of the great things about 49ccScoot – there is always someone out there that will help without making you feel totally stupid. So, I will tackle and maybe overcome my fear of carburetors. 75 to 85 range Looks like I was wrong on the main jet it’s 6mm not 5mm I would like to buy a couple over and a couple under – that would cost about $12 – kits give you about 10 jets per box, but the split seems to be right at 65 so I need to buy two sets @ $20 ea. If I want over and under. FORCE3 & BBK Kit Glad you had good luck with the FORCE3 reed valves – the cost a lot of money. Also, happy you are having good luck with the Stage6 70cc Sport Pro mkII – I saw some performance curves on them. Looks like they were built to max HP in OverRev range. Again, thanks for the reply |
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Post by 2TDave on Jun 30, 2014 17:56:14 GMT -5
No problem. Drowsports has the Vforce3 reeds for $100. I know that doesn't help now but maybe later or someone else. I use a Doppler Alien Eye($38+/-) filter from Treatland. It's kind of a hybrid between open and airbox. It has 3 vents in it. One is open and the other two can be removed.I have it with one left closed. It's not loud and rain or road water doesn't cause me any issues. I run a 102 main with it.
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Post by 2TDave on Jun 30, 2014 18:53:20 GMT -5
I edited it in my post but just to give credit where credit is due it was Oldgeek that spotted my carb problem.  |
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Post by lobarrett on Jul 1, 2014 1:00:09 GMT -5
This is the Air Box used on my Vespa ET-2.
Seems like it is a little involved and a lot of restrictions.
Air is pulled in from just under the front part of the saddle through a 1) Air Suction Pipe, it than pass through a flexible rubber tube 2) Air Bellow , the bellows is connected to 3) Air Filter.
About the only upgrade I planned on doing to it was the Malossi Air Filter element.
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Post by 2TDave on Jul 1, 2014 5:32:18 GMT -5
As long as there are no restrictions it should be fine for your set up. I think with a couple of vents in my stock air box and the snorkel removed I wouldn't see a difference in performance and could run a smaller main but I'm not crazy about the location of it for quick tuning of the carb and cvt. Scoobnz made a very nice box that I'd like to look at duplicating if I ever learn to weld.
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Post by 90GTVert on Jul 1, 2014 8:42:22 GMT -5
Here's a link that works to see all the Dell stuff that tractor site has : www.thisoldtractor.com/dellorto.htmlThe main jet is most likely to need changing, but sometimes the pilots are off. Doesn't seem like your style, but you could wait on pilot jets. Usually if I can get the idle mixture adjusted where it's not all the way in or out real far I leave the pilot alone. Not sure on sizes. The stock size in there sounds small, but I'm only used to 19mm+ Dells. Those tend to end up high 80s minimum for the main jet and some over 100 for the larger ones. I'm guessing by the 65 main that those would flood out that carb, because these are coming with 90-95 stock usually. Just a note, I don't think Malossi is removing documentation from Dell carbs. I've bought 5 or 6 new Dells and don't recall any sort of paperwork. You can make the airbox flow more if needed using UNI filtered vents. If you really want to get a lot of flow you can put them on the post-filter side of the airbox. I did that on a 103cc with a 25mm carb using a stock Minarelli airbox and never even had to change jetting swtiching from a UNI pod filter. That was a really picky setup too that took me a long time to dial in just right with the UNI pod so I was expecting another set of headaches. |
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Post by 2strokd on Jul 1, 2014 10:31:04 GMT -5
Ive seen carbon fiber reeds with the holes you speak of. I ran them without any troubles at first. This is a pic of a bigger no name cage i got from ScrappyDog years ago. The carbon did end up chipping and flaking around the edges after some use.  I used to buy and cut my own reeds. Here is a pic of Malossi,s precut CF reeds next to a sheet of carbon fiber from Malossi. I found this interesting as they were from the same company and the same thickness but yet look/feel nothing alike.   |
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Post by lobarrett on Jul 1, 2014 21:32:57 GMT -5
2TDAVE, 90GTVert, 2Strokd
I don’t know how to do a three part quote thing in one post - this is about as close as I can to it:
First let me thank all of you for the reply – feel like I have a good starting point on “My ET-2s FUEL/AIR/OIL Systems.
Direction: A Starting Point
1) Going in with the Top Performance Force3 reeds,
2) Malossi Intake,
3) Del 17.5 mm carb – will have 2 over and under on the main jets and wait on the pilot jet, and
4) Go with the stock air box with stock snorkel arrangement will wait on possible upgrades.
If any thing changes to the above direction I will update this post.
Some cool things I learned in this POST.
1) According to 90GTVert, I have style. Think that is the first time anyone even hinted that I have a style.
2) Air Box design helps reduce noise. And should be considered as an issue.
3) How to determine if you need to change your pilot jets.
4) And up jetting of mains are the norm.
5) Looks like I am good to go.
Thank you all.
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Post by Senna1Rossi on Jan 29, 2016 17:03:16 GMT -5
WOW, lots of good detailed info, sir
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Post by lobarrett on Jan 30, 2016 22:50:58 GMT -5
Thank you,
I have a tendency to get carried away.
But now that I have been gone for over a year - it's nice to read the post and replies to refresh my memory.
Thanks,
Larry
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