Vintage vespa with sidecar
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Addicted
Joined: 26 Jan 2019
Posts: 997
Location: california
Wed Feb 26, 2020 10:37 pm quote
Thanks all.
I guess the unknown is: am I going to keep stripping cylinder studs - or did the on-off-retorque of the head lead to a failed stud - which lead to the other issues. I think Craig probably has the cause of the broken gasket identified.

Considering if I will run a dozen heat cycles and see if it now holds up - or if I should take the plunge and replace the cylinder.
Then of course- I would have a whole different set of issues - like - do I go nicasiln and get one of those fancy BGM pistons or the like. I do like their shape...

Ginch - I have an iPhone with Safari as my browser - and it just shows up like that. Don't think I am doing anything out of the ordinary. Perhaps its the browser?
Voodoo - ha! indeed. I must be living well - cause that bolt could have thrashed pretty much everything - and I got away with a gas rinse of some thinly "bacon sliced" chards and not much worse. Damn lucky really. I'll make sure to say two Hail Marys and light a candle when I visit the Vespa museum in the future.

Hope to strip down chassis or paint this weekend.
Pull motor - and examine internal frame for any signs of stress after my short but somewhat aggressive initial tests.
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: 7389
Location: Victoria, Australia
Wed Feb 26, 2020 11:09 pm quote
Stripping a stud is like stubbing your toe. It happens. However I do applaud you for your creative use of a stripped stud as an excuse to buy a new cylinder kit!
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1464

Fri Feb 28, 2020 9:14 pm quote
Thatís some bad luck with the motor , I know not a lot about them but from what the guys say it is survivable.
Addicted
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Location: california
Sat Feb 29, 2020 12:29 pm quote
Quote:
Stripping a stud is like stubbing your toe. It happens. However I do applaud you for your creative use of a stripped stud as an excuse to buy a new cylinder kit!
Busted!
Took bike out for a good workout in the curves today.
Still exceeding expectations.
Just downright fun to ride.
Better part of an hour riding.

Head/cyl seemed fine with new stud - though - one never knows...
Power is great - tho not jetted in fully - still running fat.
Last ride before commencing tear down for paint.
Pondering options for addressing cylinder.

1. Received an anonymous and extremely generous offer for a Polini cylinder replacement to my cracked one - not gonna name names, but it rhymes with SoCal Guy. Would have to deck, port, polish, generally Swiss cheese it., but it means case ports would match exactly, and I would be back at ground zero for damage - not including any I do with the shaft of the grinder by accident.

2. Use a credit I have at Mercatto and get the BGM kit (see what I did there?)
3. Throw caution to the wind and go all in on the Quatrini.

Now clearly, the wise thing to do would be leave well enough alone, but wise has not really been the design path I was pursuing - so am willing to consider options more openly.

Trying to consider the pros and cons:
- Will I lower risk of soft seize with nikasil BGM? Soft seize = bad.
- How much mismatch I will find with case porting now matched to polini. Dont want to split cases.
- That BGM piston. Love the design - similar to the Quatrini. Indentations on side allow more breathing.

Know we had this conversation before - but I was ill equipped to grasp anything beyond making judgements on how cool the name of the kit sounded (Parma kit? Im not putting some cylinder on that sounds like I should have ordered it for dinner!)

Now focused on: Power/Grunt/Reliability/Case match to existing/not prone to seize.

Anyone wanna pontificate on this subject?

Screen Shot 2020-02-29 at 12.07.05 PM.png
My beloved polini. tough as stuff - but you have seized on me before... More temperamental than she looked.

Screen Shot 2020-02-29 at 12.07.47 PM.png
Quatrini - skeletal out of the box - much like where I took my polini shaping to. But it has a modern piston like the BMG design

Screen Shot 2020-02-29 at 12.09.33 PM.png
BGM - lots value for the buck it would seam. Ports look less agressive than Quatrini out of the box. Hard to tell how they will match up to my now ported cases, optimized for polini

Screen Shot 2020-02-29 at 12.09.20 PM.png
BGM piston. Looks like they took some notes from Quatrini. This indentations on the side sure make for big breaths I would think

Molto Verboso
1980 P125X, 1980 P200E , 2005 Stella 177
Joined: 20 Jul 2018
Posts: 1722
Location: Staten Island, NY
Sat Feb 29, 2020 1:02 pm quote
Just ride with what you got for a while until you need to fix something. You spent all this time and effort making it rideable and fabricated an awesome frame for sidecar. Enjoy that effort for a while! Or get a second scooter to get your mechanic fix out while still being able to ride this one!
Addicted
Joined: 26 Jan 2019
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Location: california
Sat Feb 29, 2020 2:39 pm quote
Hey - I drove for at least two hours today!
Time to rebuild!

Ha! Suspect you speak for many.

Kidding asside.
Chassis goes in for paint soon.
(not as brave as the rest of you guys with a paint gun).
That leaves motor here lonely on the bench for a few weeks.
Cylinder is less than 100% due to unfortunate user error.
I may leave as is - but this is actually a perfect time to ponder the options.

IMG_8641.JPG

Molto Verboso
1980 P125X, 1980 P200E , 2005 Stella 177
Joined: 20 Jul 2018
Posts: 1722
Location: Staten Island, NY
Sat Feb 29, 2020 2:46 pm quote
Did you tear down the frame yourself or just leaving it with them to take apart? What's something like that cost where you are? I'm curious as I am contemplating a full paint job on my Stella when I get a chance to finish it off as a theme bike. Of course, only after I get one of these other bikes running first!

Btw, your side car wheel.. Looks like it turns also? Is that optical illusion in photo or does it pivot on hinge also?

I think your cylinder is less damaged than you feel and if you give it a few months you may find no more issues. You can enjoy it while you decide! I am like you in that I did some damage and am like ok time to replace with new. Still worried about the head, but everyone keeps saying the damage is minimal so go with it until it's a problem!

Get a second scooter and you can go crazy trying out all those other cylinders on it! You know you want another one! You can't call me a voice of reason cause I'm trying to convince you to get another one.
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1803
Location: London UK
Sat Feb 29, 2020 7:15 pm quote
Just a bit of cylinder envy. Your Polini is tuned to your needs. Get 10k miles on it then maybe think about it.

Looking pretty cool. Re-paint just the same or going to surprise us?
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1464

Sat Feb 29, 2020 7:32 pm quote
Put on the new and put the old on the top shelf.
Addicted
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Sat Feb 29, 2020 10:29 pm quote
Quote:
Just a bit of cylinder envy. Your Polini is tuned to your needs. Get 10k miles on it then maybe think about it.
Ha! My favorite bit about posting the cyl question was seeing the three options - and realizing we had carved up the Polini on par with the quatrini's skeletal structure. But the question is - will my broken area hold up...

Drove it hard for about 3 hours today figuring if it was gonna snap like a potato chip quickly - might as well show itself now before I tear down the scoot. Trouble free.
Quote:
Did you tear down the frame yourself or just leaving it with them to take apart?
I've torn it down so many times now - I can't imagine paying someone else to do it. Made good with the shop that paints for the dealership a few months back. Have been dragging it up there in various forms along the way to get some advice/input - ensure I wasn't welding up some pocket they couldn't access.
Quote:
Looking pretty cool. Re-paint just the same or going to surprise us?
Have enjoyed it's rat bike status. Color will remain largely orange - but silver is gonna get swapped out for an off white highlight - exactly where is still TBD - and could be substantial. Scoot is gonna embrace its bodge roots with some two tone two part extra shiny paint work. Paint guys gave me their supplier who is in the hot rod scene here in LA. Plan to visit them and see my options.
Quote:
Btw, your side car wheel.. Looks like it turns also?
Likely the angle of camera - a bit - but yes - the sidecar wheel toes in and out ("steers") as the bike leans one way or the other. Front pivot at scoot is higher then rear - which causes this.
bodgemaster
1963 GL, 1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
Joined: 26 Sep 2013
Posts: 5131
Location: So Cal
Sun Mar 01, 2020 9:31 am quote
Hang on. Youíve got what, 5 hours on your freshly modified top end? Itís running like a champ, pulling hard (I quote: ďitís fast, almost too fastĒ) not even jetted or broken in yet, and youíre thinking about a Quattrini?

Love it!

I assume you replaced the stud that stripped. Iíd put a few more hours on it before making any decisions. It could be unrelated to the cracked cooling fin.

All that said, if want to experience the BGM now would be great time. I personally would like to see how it stacks up against your modified Polini with the GS piston and MMW head. If you just want to replace the barrel, Iíve got a Polini barrel boxed up ready to send. Happy to donate it to the cause. No bad decisions here.
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Sun Mar 01, 2020 5:53 pm quote
Quote:
Youíve got what, 5 hours on your freshly modified top end? Itís running like a champ, pulling hard (I quote: ďitís fast, almost too fastĒ) not even jetted or broken in yet, and youíre thinking about a Quattrini?
Hahaha! Indeed.
SoCal - your offer is beyond generous - and I have a few days to think about it due to some travel.

Full disclosure: cylinder post was pre-emptive to avoid time loss - wanted to hear what people had to say assuming things went south during testing.
In the mean time - swapped the stud & thrashed the engine for the weekend to see.

When I raised the question the first time... back on page 5... I got a few responses - that basically read - "choose this one" with a fill in the blank for everyone's fave. There were a few anecdotal stories about good experiences as well - which boiled it down to a few good options.

But I also learned some things after the fact - for example - it turns out iron cylinders are known to seize. (they are?! did I miss the earlier memo?!). I confirmed this for myself as you know...
🙂

As I did my first build and handled/modified the parts - I got a better understanding of how the motor works - and why the tuned kits were modified in certain ways.

The Cylinder: The mods Jack walked me through left it as skeletal as the Quatrini. I don't believe you can make a cylinder breath any more then what I did to that Polini - even by paying $400 for a Quatrini.

The head: MMW gave me a hemispherical one with great squish band. Again - check.

The rings: GS has some nice wire rings on it - and it allows a wider more modern exhasut port that matches the modern ones.

However - if you look at the piston - the upgrade to GS gets you half way there - but the shape is dated in my view. The good part are the thin rings and the thick webs around the wrist pin to allow some carving.
But with that said - what you can carve is limited - and can't match the depth of the new generation that come molded with deep indents next to the wrist pin.

When faced with it during my build - my approach was instead to cut a big ass hole just above the internal webbing (see below) and maybe I got close - but if I had my drothers - I'd have a modern piston with molded indentations (and I would see if I could polish those back a little too!)

So... My guess is - there is absolutely nothing the carved Polini cyl can't do that the BGM or Quatrini can - but their will always be a little bit more to be had out of the BGM or Quatrini due to the piston shape. Wouldn't even be having this convo - had I not done such a bone headed thing and broken my Polini. Let's hope it was just a stripped stud - and not related to that break. We will see...

kolben_quattrini_m1x_172_ccm_62mm_3_kanal_vespa_px125_px150_3330645_600x600.jpg
Quatrini has this big molded indentations next to the wrist pin. Yum!

screen_shot_2020_02_29_at_120920_pm_17154.png
BGM followed suit - maybe a little simpler mold with less undercut/ not quite as optimized.

Screen Shot 2020-03-01 at 5.41.40 PM.png
GS piston for 177 - flat sided - though they do have deep ribs to allow some carving

Screen Shot 2020-03-01 at 5.04.08 PM.png
Classic O tune work by FMP. Looks good from the outside - but that is a pretty deep cut in to the ribs that are behind

img_1540_1_16046.jpg
My solution - I didnt go deep with the indentation through the rib area - but cut a honkin big hole above the rib that connects the pin area to the skirt area

IMG_3869.PNG
While thrashing - this happened. :-)

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: 7389
Location: Victoria, Australia
Sun Mar 01, 2020 6:26 pm quote
I don't know anyone except SoCal who hasn't seized their Polini. Not a gigantic sample but quite a number.

As long as your jetting and timing is safe then I don't think you are much more likely to seize one over the other (the above notwithstanding).
But... the alloy kits are just so much better able to handle the heat imo. My Malossi 221 (inadvertently - was nightime and no backlight on the TTO) went to 493F peak over a 50km high speed ride, didn't ping or complain and kept going.
BGM is a great kit but I'm with everyone else - use the Polini until it can't hold the head properly any more. Which is likely to be forever unless you seize it first.
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Mon Mar 02, 2020 12:41 am quote
Quote:
Which is likely to be forever unless you seize it first.
Well - I tried over the weekend - but the damn thing just wouldn't die.

Good stuff on iron vs aluminum.
That's the type of insight I was looking for - understand lay of the land.

I'll have a close look at the cylinder sealing surface & the head - make sure no other leaks were starting based on this weekend's escapades.
Assuming no - will bolt it up and drive with confidence.
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1803
Location: London UK
Mon Mar 02, 2020 1:16 am quote
Once your Polini is actually set up (jetting and timing) it should make a bit more still. No doubt you will see 70mph on your phone.

It's not going to leak. Will be fine forever.
Addicted
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Fri Mar 13, 2020 9:41 am quote
Side Draft Carb - it begins.
Ok - been hanging out on a few of the other threads - but back to business here.

Preamble: before I am accused of unthrifty spending (the irony of which on this board is thick enough to cut with a SIP special tool you bought) - let it be said. I have one scoot (currently...) and I picked it up for less then $3K with side car. I had a bigger budget, but this has always been about the joy of doing the build myself and making something unique.

I hate waste. I am a folder not a crumpler.
I also love making lemonade out of lemons.
With that said - I'm too set in my ways to drink high fructose corn syrup crap - so ingredients and process are key.

I bypassed the 26/26 SI on my build based on more then a few telling me I would be at the jetting for a long time (read - always fiddling).
I considered side draft (and eventual reeds) but it seemed too far away when I started.
SDJohn had just detuned after some 40 pages trying to jet in a side draft.
So 26/26 and side draft were off the list.

Yesterday, Swiss posted a side draft carb that touts itself as mostly self adjusting. No jets - simplifies the process.
Bit of research about the tech - and review by SIP suggest it has some cool benefits.
Primarily - super efficiency on gas, smooth factory like throttle response, while still giving HP gains at top. I was hooked.

They seem to achieve that curve by using a Venturi shape that is like an upside down egg - lower on the throttle - you get behavior like a smaller carb. Wide open - you are like a mikuni. So... I am going to give it a go.

Looking for input and questions I should be asking.
Starting point:

I'm still rotary - roughly 120/60 = 185 crank timing.
123/127/27 port timings.
24/24 carb.

Their carb has a 35mm outlet to the engine side.
I have a welder & a tube bender.
Am I making my own manifold - and using radiator hose & hose clamps to isolate carb - or has someone done that work nicely for me that will bolt on my motor?

Air filter side of carb is 1.74", but they offer an adapter also = 2" (50mm). What about that side?

Everyone invited to play along!
-CM

Screen Shot 2020-03-13 at 11.21.16 AM.png
35mm side is to engine - how do I get from case to back side of carb? welder and tube bender? is there off the shelf solution that allows reeds down the road but runs without in mid term?



Last edited by charlieman22 on Fri Mar 13, 2020 10:23 am; edited 1 time in total
Molto Verboso
08 GTS 250, 79 P200E, 62 Allstate
Joined: 11 Jan 2006
Posts: 1478
Location: Florence, OR
Fri Mar 13, 2020 9:52 am quote
This should be fun to watch from the sidelines!
Molto Verboso
1980 P125X, 1980 P200E , 2005 Stella 177
Joined: 20 Jul 2018
Posts: 1722
Location: Staten Island, NY
Fri Mar 13, 2020 9:57 am quote
Im not criticising the spending cause I'm right there with you irrationally spending and even suggested you get another scooter! As whodats suggested in the other thread, that carb isn't really fool proof and still takes setup but could have some benefit that you mention. I'm curious about it but it's too much for me especially losing my job to Corona virus yesterday. Keep us posted!
Hooked
1984 PX(BGM187)EFL
Joined: 14 Apr 2017
Posts: 302
Location: Cornwall UK
Fri Mar 13, 2020 10:16 am quote
We might pull your leg CM, but nobody's gonna criticise you for scratching the itch, and we know you'll do it justice with your attention to detail and skills. As to whether or not it's worthwhile, or money well spent, I haven't got a clue; didn't look at the price, and still haven't, way out of my league in know-how and wallet. - Lemons? - luxury!

What could possibly go wrong!
Ossessionato
Joined: 26 Oct 2015
Posts: 2186

Fri Mar 13, 2020 1:50 pm quote
Before you plunk down on the Mensa carb...just remember how many times in the past all of us have suffered at some point from SIPs descriptions (or lack there of) of any and all of their high end tuning parts. Just sayiní.

One of the reasons the Smart Carb is supposed to get better fuel economy is that it doesnít have an overflow hose (the Lectron does). What that means in the dirtbike world, is that when youíre going through whoops, jumps, steep climbs and decents, is that fuel doesnít leak out like a stock carb would. Thatís number 1 reason why it gets a better fuel economy. If it was just on smooth road, those high tech carbs arenít going to provide much of a fuel economy boost over a stock carb. I hear lots of stories of guys installing the fancy carbs, only to remove them once they canít get them dialed in correctly. Once their original carb is back on, they are happy with the way the bike performs again.

I really believe that 95% to 99% 2T bikes (scooter or any modern dirt MX) wonít benefit from going with one of those carbs. Though Charlie, you do seem to have pretty good luck with everything thing you touch so far. I just see everything as a ďdollar to 200cc ratioĒ. If I spent $500 on a carb, that means I would be close to one third of the way to buying another P200 engine!

Lots of discussion regarding all those carbs on ThumperTalk, KtmTalk, and Advrider (in the KTM 300 subforum). Maybe lurk over there to read up on it.

Last edited by whodatschrome on Fri Mar 13, 2020 4:08 pm; edited 1 time in total
Molto Verboso
1980 P125X, 1980 P200E , 2005 Stella 177
Joined: 20 Jul 2018
Posts: 1722
Location: Staten Island, NY
Fri Mar 13, 2020 2:40 pm quote
whodatschrome wrote:
Before you plunk down on the Mensa carb...just remember how many times in the past all of us have suffered at some point from SIPs descriptions (or lack there of) of any and all of their high end tuning parts. Just sayiní.

One of the reasons the Smart Carb is supposed to get better fuel economy is that it doesnít have an overflow hose (the Lectron does). What that means in the dirtbike world, is that when youíre going through whoops, jumps, steep climbs and decents, is that fuel doesnít leak out like a stock carb would. Thatís number 1 reason why it gets a better fuel economy. If it was just on smooth road, those high tech carbs arenít going to provide much of a fuel economy boost over a stock carb. I hear lots of stories of guys installing the fancy carbs, only to remove them once they canít get them dialed in correctly. Once their original carb is back on, they are happy with the way the bike performs again.

I really believe that 95% to 99% 2T bikes (scooter or any modern dirt MX) wonít benefit from going with one of those carbs. Though Charlie, you do seem to have pretty good luck with everything thing you touch so far. I just see everything as a ďdollar to 200cc ratioĒ. If I spent $500 on a carb, that means I would be close to one third of the way to buying another P200 engine!
This I agree with. Spending $500 on carb.. when I spend $500-800 on thw whole scooter is a bit irrational!
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: 7389
Location: Victoria, Australia
Fri Mar 13, 2020 4:54 pm quote
Re: Side Draft Carb - it begins.
charlieman22 wrote:
Their carb has a 35mm outlet to the engine side.
I have a welder & a tube bender.
Am I making my own manifold - and using radiator hose & hose clamps to isolate carb - or has someone done that work nicely for me that will bolt on my motor?
WDC could be right here, he often is! All I know is that you read about these carbs on 2 stroke forums and you get the similar responses, some think it's great, some think it's snake oil. However if it's really easy to tune then that could easily tip the scales... as for John and the 40 pages, I would have been perfectly happy to run it at 350 degrees, cut it short to 20 pages and kept the scooter!

Now, back to your question - because you seem to Get Things Done, and I live vicariously through that! Yes someone does make a manifold that will suit that (and pretty much every 30mm side draft carb), a number of people do. This is the one I like... part of a reed setup (just put those bits aside for later on your ever-burgeoning shelf) by Pinasco, although Malossi make one almost exactly the same for exactly the same price.

https://www.sip-scootershop.com/en/products/intake+manifold+pinasco+sla_25381100

Pinasco would need a plate between the manifold and case to adapt, also a 'stuffer' (not really a stuffer but simply a 'dummy reed' to direct the flow to your rotary valve, also to give the plate that holds the base of the rubber something to sit on. Could even be a reed cge without the petals.).
Pinasco advantage over the Malossi here is that they use a RD350 reed, Malossi use their own design (pretty sure that's correct as I can't find it anywhere else), which means you have a greater choice of reed blocks, petals and styles, theoretically even V-Force.

I see the advantage of this style over the MMW type is that this provides more vibration isolation, and is quite low and compact. It also keeps the intake short by not having to use a rubber connecting sleeve. Whether shortness is good or bad, dunno!

https://www.sip-scootershop.com/en/products/intake+manifold+kit+malossi+_20149130

Pinasco


Malossi
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Location: california
Fri Mar 13, 2020 6:00 pm quote
Gents - gold as usual.
It is my self assigned job to be the Labrador retriever of this forum.
Throw me the ball. Throw me the ball. I'll fetch! Who's a good boy?!

Drop a screw in your motor when it's running?
I say: was it over when the Germans bombed Pearl Harbor?! Hell no!

Lemme take these one at a time:
Whodat - your insights from dirt bike world are good ones to bring. Chatted with Kristian at BarItalia t'day - ironically while picking up a 135 jet for my 24/24. He rode one of the early Lambretta tanks with a lectra on it. Said: hands down the fastest street bike he had ever been on (stop sign to stop sign). Smooth as well. Was not familiar with the meltdowns you note... but I don't doubt it a moment.
Tuns out the carb guys are still iterating their product - so we know it can't be perfect... but then - what is? ( more on that in a moment.)

New stuff from SIP that is shiny and expensive with some marketing hype is a dime a dozen. It's not IF this falls on that spectrum - but WHERE. For me - the hook is in the simplicity and smoothness promised - in a larger throat carb. I chickened out on the 26/26 just to avoid that - and didn't even reach for the sidedraft (though I looked at it...)

Fuel efficiency - I think these guys save more then just by avoiding spill over. They claim to be atomizing it better - and I like the concept of smaller throat at lower slide opening/ upside down egg shaped Venturi. We will see.

P200 motor. You made that call out of the gate - and my cases are particularly prone to melt down as they spent allota time in Indo doing hard work - so that point can not be argued. That said - that ship sailed when I went all in on the EFL and cylinder kit(s). Anyway - I was always a 4 cylinder guy in my past life - so why change now.

Full disclosure. (realize this is gonna sound familiar) I wiggled my way into the expert there and had a good tongue wag. Turned out he had a 25mm with their latest upgrades and light use that I can play with. They are in development of a few larger ones in 26/27/28 that will have this new config already on the 25mm - but are not ready until mid summer (which I read to be late fall...)

Highly knowledgable and liked what he was selling. Struck a deal for the 25mm for now - which will be pretty close to a swap to may 24/24 in size - and we can all know then just how well their tech works - before this goes reed and bigger bore... Just being honest.

Later in summer - I will swap it for a larger one if I want to. Hard to say no to that - especially after the guys gave me that kinda time.

Ginch - braced myself for the Southern Hemisphere coming on line. Your whole first paragraph cracked me up. Info that followed was exactly what I was looking for. Tks!

Compact/low vibration were high on list.
Malossi tempting for simplicity.
Pinasco for flexibility in reed choice.
Kinda excited to see what the carb will do with just the rotary - and then experience what using reeds do at some point.

Work travel pretty well grounded to a halt.
Fridge full of good things to eat and drink.
Coffee stocked high.
Its as if the Vespa Gods are saying: Charlieman - now is the time.
Who am I to argue with this I ask?
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
Joined: 14 Jun 2017
Posts: 1803
Location: London UK
Fri Mar 13, 2020 7:26 pm quote
Well this is going to get interesting.

I would think finishing the set up of the SI carb would be where to start. From a scientific perspective at least you would have something to compare against.

The 24/24 sits right on the crank without a manifold, so actually works like a slightly bigger carb. If you put on a 25 at the end of a 3 inch manifold it will feel smaller.

My feeling is once the SC is set up (this is going to be riveting) its going to be lovely and smooth but not quicker in any way. Although if you ever find yourself riding up the Khyber pass it won't need a re-jet.
Addicted
Joined: 26 Jan 2019
Posts: 997
Location: california
Fri Mar 13, 2020 8:34 pm quote
Jack,
Thanks for weighing in.
Interesting point on distance.
You will have me upgrading to the 36mm by end of summer...
Let the sciencing begin.

Agreed on 24/24 - which is why I was picking up the 135 main today. So Ur not off the hook.
Letís jet this thing in.
If it will stop raining here, will post some info and stats of where I am at.

I have my butt dyno and a better than avg ear but canít really understand half the gsf dyno thing.
Willing to record some runs with phone in same relative place on same section of road if anyone can translate that wav file into something of meaning. Hell - Iíll weld a phone holder on if it makes it better. Need direction. Sime?

As for new carb - learned some stuff on first call. Need to revisit a bit better armed. We can ask guru any Th omg we want.

They are doing some ďpre-tuningĒ, my term, before they ship. Iíll get a better understanding of what levers they are pulling with what components - but hereís a set of first clues to ponder.

*They seem highly focused on what mixture ratio and fuel type Iím using - highly important - more so than precise motor specs. Thought that was interesting.

They are using a needle and seat that is appropriate to gravity feed - which I like. No pump needed.

They believe they excel in over rev vs SI and others. They also believe they are more set it and forget it for temp and altitude changes. Could have relevance on sea level to mountain runs in this area. Socal is always threatening to drag me along so canít seize and screw up the ride.

My next set of questions to understand from their guru is focused on what ďpre tuneĒ levers they are pulling to set up the carb.

Anyone Want to pontificate on why fuel mixture ratio is so critical to their set up?
Molto Verboso
1963 VBB2T
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Posts: 1464

Sat Mar 14, 2020 12:25 am quote
qascooter wrote:
This should be fun to watch from the sidelines!
Oh how I agree
Molto Verboso
PX221 Malossi, O tuned PX200 and some motorbikes
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Location: London UK
Sat Mar 14, 2020 4:36 am quote
to keep the argument balanced
Molto Verboso
1980 P125X, 1980 P200E , 2005 Stella 177
Joined: 20 Jul 2018
Posts: 1722
Location: Staten Island, NY
Sat Mar 14, 2020 7:30 am quote
Jack, that was painful. Seems to me after reading their website and hearing charlies experience, that they grill you on your setup before mailing it to you so that they can set up the carb with what they think is appropriate needle for your setup. I find it amazing that guy in the video dropped $1400 on two separate carbs, when all he had to do was ask them to send him the new needle they installed into the new carb. Also seems like the smart carb still takes needle adjustments to dial in correctly after reading the comments on his video. So maybe he should have asked them to send him a range of needles to try until he got the one that worked.. then sent the rest back.

Regardless, smart carb is only smart after you jet it! Just like a regular carb!
Addicted
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Location: california
Sat Mar 14, 2020 8:33 am quote
It is not the jetting per say that they are altering for the different bikes - but I will go back and find out exactly what parts they play with for sending out for a Vespa, vs a KTM for example.
Jack - perhaps you will have an opinion or some input for them.

These guys are in to what they do.
My expectations is - if we are willing to share our experience back with them so they get "smarter"/ they will work with us to optimize for our application.

Interesting that guy was simply no where close in the vid Jack shared.
Here is another vid - which I found interesting.
Three guys - same bike - three carbs.
Lectron/Mikuni/SmartCarb
Day long ride.
Swapping bikes around to compare.
Start at 6:09 if you want the recap.
Reader's digest: Smart and Lectron were smoother through whole range.
Lectron was smooth down low - but at the cost of some grunt
Mikuni was way grunty but a little boggy with some flat spots throughout.
Smart was smooth and grunty from bottom all the way up

Clearly - having the right components inside are going to make a difference.
Likely - get right insides and you get advantages of that smooth curve.
Low end performance of smart carb could be related to their upside down egg Venturi.

My expectations/desires
1. Go side draft without making it a 6 month process.
2. Get better fuel economy (believe related to smoothness through range)
3. More top end than I can get out of an SI
4. Smooth torquey non 4 stroking bottom end out of the box (tough with big ass side draft...)
5. Not have to fiddle when I go on rides - hot day, cold day, rainy day, hills, coast. In other words - have a great set up that was also super robust.
6. Be able to graduate up to a big ass sidedraft and keep all of above

If that went down - I'd put it in the win column - and consider it a good path for people in my demo to play in the sidedraft world - on daily driver.
If it's a disaster - I have a space on my work bench shelf for a holed piston as a trrophy - and my 24/24 SI ready to go back on.





https://youtu.be/LpFg8oNONV0?t=369
Ossessionato
Joined: 26 Oct 2015
Posts: 2186

Sat Mar 14, 2020 9:24 am quote
What you may not know is that the carb comparison video is missing a 4th carb in it's comparison, so it is kinda biased...

KTM switched over to assembling there 2T bikes (i think in 2017?) to the Mikuni (4 steps backwards). Well, the Mikuni sucked enough that guys were installing any other carbs that they could get. Ideally, they would just buy a used Keihen PWK that came off of the 2016 and older KTM models. That's why so many dirtbike guys were buying the Lectrons and Smart Carbs...because finding a used KTM Keihen PWK wasn't going to happen. Now that all of their 250 and 300 2T bikes will only be available in 2020 in a FI version, there's no need for KTM to use those Mikuni's anymore.

Smart Carbs are advertised to only use the amount of fuel that your engine needs...which is true in the sense that if it's adjusted correctly (in other words "jetted"). If not, it's just like any other carb...you get a hole in the piston! And the carb will still need "adjustments" just like any other carb would when riding in crazy elevation gains...let's say from about 3000' changes and on up. I think the most critical part is to have a person who is highly versed with those Smart Carbs at your disposal at a moments notice...which might be kinda tricky. When i had a Lectron on my KTM, i would call their tech department. While they were more than willing to help and give tuning advice, in the end of the day they are their to sell their product. So if something wasn't running correctly once their carb was installed, they would usually claim that something else was the matter with my bike.

I'm not opposed to anyone converting over to a Smart/Lectron type carb, i'm just opposed to the way they advertise its benefits over a properly jetted modern carb.
Addicted
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Location: california
Sat Mar 14, 2020 9:43 am quote
WDC - good insights.
I'm going in with eyes at least half open...
Which is to say - hopeful and willing to try.
Keep in mind - part of this game is - can the half witted put a sidedraft on to their scoot successfully - and have a smooth power curve.
We will see.

Below is a vid link that explains the tech of the lectron if anyone interested - which I believe is basically same as smart.
Makes it simple to understand how these things work.
The metering rod taper is basically 90% of it.
The clicks raising the rod or lowering it move you richer and leaner in that scale.
The taper gives you the profile from bottom to top of how much fuel/air.

My guess is, the questions they ask before sending your carb are directly related to the choice they make on the metering rod. This is where I would be willing to do a little R&D for the vespa crowd. I may ask them to bracket me - offering options that I can give feedback on - understanding that would extend the work of "jetting" in. But I will see how close they are out of the gate first.

Off to jet my SI...

https://www.youtube.com/watch?v=MrDoA25r5X4

Screen Shot 2020-03-14 at 10.36.59 AM.png
Pretty cool shot of what they claim is a better spread of the atomized fuel. The metering rod is center - fuel climbs up it. See vid.

Molto Verboso
1980 P125X, 1980 P200E , 2005 Stella 177
Joined: 20 Jul 2018
Posts: 1722
Location: Staten Island, NY
Sat Mar 14, 2020 10:02 am quote
Yes what i meant when i said needle was that metering rod which their literature seems to suggest is the deciding factor on when they query you for your setup. If that is the case, just a metering rod set is useful to "jet" it properly. But then, you are no longer smart carb, but another form of jetting carb.

Also.. given the requirement on the smart carb website that they ask you about your setup in detail.. makes the concept of purchasing one of these smart carbs from SIP kinda useless.. cause you are gonna get a generically set up carb from SIP as opposed to the "kinda dialed in" carb direct from them.

Regardless.. Charlie, if you've got an in with them and they are looking for 2 stroke vespa guinea pigs like us.. I'd be willing to take one for free and give them feedback?! But might be better if they offered them to Jack/Whodats/ginch/sime/etc.. who are way more knowledgeable about such things to provide real world feedback!
Ossessionato
Joined: 26 Oct 2015
Posts: 2186

Sat Mar 14, 2020 10:06 am quote
And those Lectron metering rods aren't cheap (they cost way more than jets!). And you usually need 3 or 4 of them by the time your done adjusting the carb...even though the carbs are sold with the ideal bits when you initially order it (according to your engine CC's, extent of engine tune, elevation, riding style, ect..). I just want to get all the information out here in the forum so that everyone can see what all else may be required to purchase to get the carb tuned in...just so that there's no possible future surprises that pop up.

I'm still hoping for a fuel injection auto-lube conversion in the future!
Molto Verboso
08 GTS 250, 79 P200E, 62 Allstate
Joined: 11 Jan 2006
Posts: 1478
Location: Florence, OR
Sat Mar 14, 2020 10:14 am quote
whodatschrome wrote:
I'm still hoping for a fuel injection auto-lube conversion in the future!
Now that would be cool!
bodgemaster
1963 GL, 1976 Super (x 2), 1974 Primavera (x 2), 2006 Fly 150
Joined: 26 Sep 2013
Posts: 5131
Location: So Cal
Sat Mar 14, 2020 11:01 am quote
Donít see any real benefit on a stock set up ... I think the real benefit is that it could save hours and literally hundreds of dollars of fiddling around trying to dial in jetting on a finicky modded bike.

The automatic AF metering is an interesting feature. Not sure how important it is for everyday riding, but a definite plus for elevation and temperature changes. On the last ride up to the mountains most of us were too lazy to downjet ...

Give it a go. Thereís no downside. If it works, itís money well spent. If it doesnít, consider it another donation to the scooter knowledge fund.
Addicted
Joined: 26 Jan 2019
Posts: 997
Location: california
Sat Mar 14, 2020 11:59 am quote
All valid points.
Here is one to balance.

Hereís a hypothetical - think of it as me asking for a friend.

Letís say u like to run ur bike hardish - and ur goal is to be able to Cruz at hwy speed pretty well WOT.

You start fat and then walk the jetting down and get to a great feel. Say 135 main.

Then u figure. Hey. There is no one on the road today really, letís just see what 132 will do? Right?!

U take off on ur same speed run. It feels ok - but u can tell itís n it as sweet as ur 135. Still, this is science and the run isnít that long.

On return u feel a hickup and then SCREEEEECCCCHHHHH eminates from ur back tire as the seized wheel tryís to pass the front wheel and u feel urself counter steering.

Then - and Iím just talking about my friend here of course - u pull the clutch - but gingerly - cause u donít wanna get catapulted and u go to coast.

Cause u - I mean him - weíre doing 65, there is plenty off coast left in the bike as u roll to a concise toy places emergency parking pull off.

U look down at the temp - and sure enough - it is in that magical no go zone of 311. You can kick the bike over - cause there is no compression.

Since ur on your phone, waiting for a tow, u have to post pictures separately as you wonder - why didnít I drive on the 135 for a while and see how itís temps were?[/i]

BAD769F1-C950-49E2-8C66-EAD8A9D14B0E.jpeg

Molto Verboso
08 GTS 250, 79 P200E, 62 Allstate
Joined: 11 Jan 2006
Posts: 1478
Location: Florence, OR
Sat Mar 14, 2020 12:09 pm quote
DAMN!!!!!! That sucks for you, er, I mean your "friend".....
Addicted
Joined: 26 Jan 2019
Posts: 997
Location: california
Sat Mar 14, 2020 12:24 pm quote
Yeah. What a dumb ass - he is.
However. We did get the data on best jet so I know what top speed and to an extent even acceleration was with the si carb on best jetting.

Probably a little more wreckles then I needed to be - but wanted to know what those numbers were with SI before trying the other.
Molto Verboso
08 GTS 250, 79 P200E, 62 Allstate
Joined: 11 Jan 2006
Posts: 1478
Location: Florence, OR
Sat Mar 14, 2020 12:35 pm quote
I appreciate you taking one for the team, in the name of science CM!
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1464

Sat Mar 14, 2020 2:38 pm quote
That really sucks, I didnít realize they were so sensitive.
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