Modern Vespa

Be careful mixing and matching "short" 4th's...
A T5's 36 tooth 4th gear will only fit the EFL transmissions. If you want a shorter 4th gear in a non-EFL P200 gearbox, you will use a stock 36 tooth 4th gear out of a non-EFL P125.

Ha ha! When I got my first short 4th, I discovered this fact... could have put the old one back, but hey, all I was missing now was an EFL drive shaft, 3 gears, an input shaft and I was there! Education, huh! Sometimes it costs just a little more than you imagine.

I didn't actually put a short 4th in my Stella. I've just read the Stella gearbox is the equivalent to a p200 w t5 4th and that calc seems to line up with my real world results when I use that setting. But that is good information to be aware of if ever I do change 4th for short one.

Don't know much about transmission options but on my GL 150 with the previous alum Pinasco cylinder design I used a 64/23 straight cut primary. This engine has plenty of power and torque with a 24mm carb and 57mm crank. But after working on my latest Bajaj engine and all the learning I have gained in the last few months when I am finished with the Bajaj I might go back into the GL and tighten things up.

After building the GL I discovered how much fun the 150 is. For me 45-55 MPH is plenty fun and knowing I have so much more makes 45 so easy it almost drives itself. It might also be a sign of age and slowing down. Sorry for my rambling on my next build I decided to explore how a 60mm crank changes things and left out the overdrive. We'll see if that was a good decision soon.

On the 60mm crank I decided not to use the flywheel side seal modification. Can't remember why exactly I did not pursue it but the times I've had seal issues they've been on the clutch side anyway. Although you've had a seal issue Charlie I did not feel the modification was worth it. Hopefully this does not prove to be an oversight. Think there was one posted on here several months ago.

And you know the advantages and options for flywheels and stator plates.

If my understanding is on track the longer the inlet duration the broader the power band? When I started with the 60mm Mazzucchelli the factory inlet pad duration was giving us 149°. After enlarging the pad and cutting the crankshaft we reach 187°. I don't know exactly what this means but that is what I know.

Got confused by this and just realized I have EFL gearbox in my stella as mentioned on my thread:
https://modernvespa.com/forum/post2346140#2346140

Mentioning it here for completeness regarding charliemans discussion about which scoots have EFL vs non-EFL gearboxes. Stella/LMLs are EFL.

Gents - as usual - many thanks for the inputs - all of 'em.
Ginch - took me a moment to realize - you had one wrong gear (EFL) and ended up building a whole elf transmission around it. Thanks for the chuckle.

Transmission:
Whodat - think I have finally sorted out the efl components. Not sure I can get back to my target ratios - but using calc, looks close. I think I can use my existing xmas tree shaft (or new) but will need new set of cogs for it- and then a full set of new cogs and output shaft on the drive shaft side (some of which I need anyway).

Looks like I have some travel that will take me near SC and SIP at end of month. Wife is starting to question if my "work travel" is being determined by my parts needs. Pfff. the nerve. Honestly.

I plan to tear down before I go - have good look at wear parts and take some key measures - hell - just drag the xmas tree shaft with me if I have to. I'll get a chance to confirm all cog counts - and see how close I can get on drive ratios with elf options.



Crankshaft: Ha! I could have written that myself.

Sime66 was kind enough to give me some targets - suggested 123 degree crank target
That happens to be what the Pinasco available for my cases is.
Like that - but concerned that if I find my rotary pad has been dremeled previously - then I might have too long an open duration in combo with the cut crank. Thoughts?

Given history of this bike - crank is going to get replaced when I split no matter. 60mm and well tuned is target.

Yes, the Stella/LML is EFL...well, EFL "style" that is. The Piaggio EFL and Stella gears and shafts can be mixed and matched. But the Piaggio gears and shafts will be much more durable. That also means that the even more durable DRT EFL gears can be swapped into the Stella as well...if you have the funds, that is.

times three, inlet, transfer & exhaust 123

Hibbert - I suspect you have something important you are telling me - but its as if you are trapped under a heavy object and can't fully reach the computer.

Or perhaps I'm just dense.

Can you elaborate just a touch?

I think this crank will work out. There isn't much pad to cut on a VBB.

CM, be a bit careful with your timings; those numbers I gave you were what I had in mind for my build, it doesn't follow that the same would apply to yours with whatever engine your building and your sidecar. I'd ask here, from those who know your build, for better advice on it.

(Also, the 123 was my target Transfer timing, not crank timing; I'd just listen to Jack, who's posted above)

Gents,
Work has gotten the best of me the past 10 days - and when there has been a window - I have chosen to ride rather than type or turn wrenches. Been fun. Sime - makes sense. Saw sufficient parallels in mine compared to your target performance - so it seems a reasonable. You put it in bold on Hibbert's thread - tho from my post, one might think my reading comprehension/ listening was poor... I plan the dry build and measure method - then adjust (or ignore if its reasonably close). Jack - thanks. The Pinasco has a longer opening duration off the shelf (think I have the terminology correct) than the Mazzuchelli I would prefer not to have to cut the crank - ik, hard to imagine there is a part I don't want to cut - so the Pinasco is top choice on this front.

However - just got confirmation from friends across the pond that the Pinasco is std VBB/Sprint taper... Mazz is PX.

Inclination is to go with the Pinasco and live with the taper - unless you guys are waving red flags on that.

Also have to determine if I am going to mount a 24/24 or a 26/26 on top. Will I loose some off the line grunt with the 26?
Are they tough to jet compared to the 24?

Headed for some travel that takes me past scooter center and Sip in a three day window. Hope to tear down the motor before I leave - count the teeth on the cogs, grab the output and xmas tree shaft dimensions, etc. then fill up my bag with tidbits. I will assure the border duty officers - and my wife - that there is no more than $100 of parts.

Looking forward to tackling.
Hell - I still have to make my side car lean!
Lots to do.
-CM

I had zero luck trying to dial in my 26-26.

Whodat - thanks!
Have continued to search - and continued to find others with similar experience.
Seems like it can be tough.
Sufficient for me - I'm headed to the 24/24 for dial-in-complexity reasons based on what I've seen.

My goal here is to solidify my machine with this rebuild - crank needs to be replaced. So does output shaft.
Since they have to get changed, I am going to upgrade...
60mm for the crank & EFL conversion for tranny.
Variable timing, and a 24/24 will also be added in search of a little more oomph.
Of course I want as much reliable power as I can get from this.

Currently if it's windy or slightly uphill, hard to make the bike climb over 5800 RPM. If I get my 4th gear drive ratio right, maybe I can squeeze a few more MPH out of the top speed on efficiency/power band matching.
As noted previously - it feels a little tall.

Anyone have a guess as to what the HP increase will be of adding the 24/24 and crank? Assume there is at least something left to squeeze out with those upgrades.

Thanks!
- CM

Charlie, with all those new fancy parts your throwing at your smallblock case, you could probably spend about the same amount of money to build a stock 200. Just sayin'...
I guess you'll get a better idea of what your plan is once you split the cases though. But just think...a stock 200 cylinder with a 24/24 carb, EFL 200 transmission with a shorter T5 4th (36T) gear, and maybe drop to a 22 tooth clutch, and a 65 tooth primary. That would get the side car moving up hills. Maybe another gear ratio could be the 200 transmission with a T5 4th, 23 tooth clutch, with a 68 tooth primary? Anyhow, maybe make up a spreadsheet to see how much more a stock 200 will cost, compared to a mild tuned smallblock?

24/24 will be less power at than a 26/26. Pretty sure thats not the plan.

I think Pinasco crank with small taper will work out ok for this build, as you already got the variable flywheel kit to go on.

There is no way we are going to let this be less powerful than a stock 200. Probably will end up at least 15bhp with all the grinding in the right places.

Whodat - your a good man for watching out for me! Thanks.
In truth, even if I had a set of P2 cases sitting on the bench right now, it would be hard to let this first motor go. Still the orig cases for this frame - and running so well right now. If the output shaft were not demanding it - I would be working on the side car rig and my welding skills.

The rough math: I will put about $500 in to this. More if you count that nice ignition system and new gears (see what I did there?)
P200 would be $1000 of cases, plus a clutch, and if honest, probably a cylinder and piston. Of course, I might want variable timing and the same set of new elf gears... then there is the exhaust. I could probably get to north of $2K pretty quickly.

But with that said, I am keeping my eyes open for a P2 full bike. I would use the fork for my VBB electric project of the future, and then that motor would be calling my name for a Malossi touring build. But one bike at a time - for now! Jack - I know reckless advise when I hear it - So your on - against my better judgement. I'll do some shopping while Im there and choose a carb. That sound you hear in the background is my dremel warming up.

I guess it would be pretty boring around here if everyone converted to a stock 200. All the threads in the NSM section would go something like this..."so i swapped in a P200 engine in my xxxx scooter 6 months ago, and it runs strong at 60-65+mph. It been dead reliable. If fact, i haven't even needed to install any sort of CHT gauge either! Now with all this spare time i have on my hands, (because i haven't been tinkering in my shop because the scooter runs very well) the wife/GF/lady friend, S.O. has me out painting the house and doing land scaping."
Also, all the threads here would be less than one page long. It would go something like this for the tech questions..."i just swapped over to 200 cases in my xxxx scooter. Should i keep the 8" wheels like Ginch did, or convert my front fork over to a 10"? And other questions like..."which box exhaust should i get for my stock 200?" Also.."which main jet should i install in my 24/24 carb, the 122 or 125?"

But i realize that not everyone likes it like that. There are all types here on the forum. Some are tuners, some are street racers, some race on the track, some like to ride only to church on Sunday's, some don't like to ride at all and just use the scooter as a show piece in the living room, and others are day in day out commuters. My thought is that for every tuned scooter that you own, you should have two stock 200cc powered scooters (for when the tuned engine is on the work bench).

Oh man - I had a good chuckle. Mostly because it's true - and funny shit is always based some form of truth that's right in front of your eyes, but hardly noticed.

I'm looking forward to building this thing. It's no accident I'm opting for a new crank and the EFL tranny (you suggested). I'm building in some toughness - but it's true the NSM forum is littered with melted pistons. Hell - Safis's was spectacular in its depth without going through - still don't know how he did it. Craig looked like he left a cigaret burning on the table... For a week. SoCal ripped the rings from the piston like fingernails from a prisoner in some kinda medieval torture, and Swiss, Swiss looked liked he tried to re-forge the piston - while it was still in the cylinder. And that was only last month's list. I'd need another page to cover SubEther's escapades.

The 26/26 carb on the other hand is full of risk and misery. With that said, the challenge has been set and Jack says we are gonna make this thing go - so the challenge is on.

If we make it work - I will title and post - how to jet a 26/26 carb successfully thread. Best I can tell - it would be the first.
If I cross the point of too much time on the bench, not enough time on the road, Ill pull the 26/26, put it on eBay, and get a 24/24.

As for reliability - if I do it right, my electric build will be my super reliable ride. turn throttle - zip forward - every time - all the time. Biggest risk will be: did I remember to keep it charged...

Love NSM and all you guys bring.
- CM

I like this - a lot!

I know a guy in France who - with the help of Hot Rod Al - is further developing the Vortex carb. It incorporates a proper venturi in the intake, not just a bellmouth and extras. Early testing is looking good.

Do they need any Beta testers?

But you strike an interesting point...
So I thought I would garner some opinions for a change.
SIP offers a few options on the 26/26.
There is a Dell Orto that they have bored out & increased the whole size on.
There are two - a G & an E. G appears to have a shorter throat.
I plan to run a bell mouth opening on it.
Like the way that performs particularly at the higher RPMS.
Looks like the G is more desirable - if the benefit of the shorter throat is real and performs well with a bell mouth.

Or...

I go with the Pinasco 26MM which is also drilled out in all the right places- and conveniently comes with a bell mouth on it already. No idea if it is a shorter throat model, if Pinasco knows anything about carburetors, or if it is just a rebadged model G or E from Dell 'Orto.

On the G carb they use a different idle jet to which there aren't any other sizes than what comes with it so that is something to consider

Other than appearance what's the difference? Don't do it chazman. 40 pages of jetting minutiae and frustration ahead

Hiibbert - thanks for the input. Gracious - that is not a small detail.
I couldn't find anything on SIP or SC that mentions this "minor" inconvenience - and when I say minor, I mean the English understated kind of minor - like having your leg blown off, or backing your car through the garage door.

SoCal - your equally subtle view point is duly noted. Techs at SC/SIP will of course be queried while I am there, to, uh, get another opinion...

Hibbert - is there any place you can point me to with some info on this?

Tks!
-CM

It's been a while since I messed with the short intaked carb (T5), but I remember something about cutting down the standard length jets to fit the T5 length carb. I don't know what that does to the air and fuel flow though.

Amazing what firing a post up here can do before I go off 1/4 cocked.
Now I am just going off half cocked.
Much better!

Putting Hibbert's and Whodat's together - along with a closer look online at the pics, the shortened version appears to require shorter jets.
Am assuming that the idle doesn't come in a shorter option.
Thus you had to cut some down.
Seems a little crazy that no one turns them down and sells.

I'll double check it with the folks at SC/SIP but think I have my head around it.
Would not want to have to mess with cutting down jets myself.
Good head's up on all.
Tks.

The intake on an SI carb is straight. On his there is a taper from the top and bottom so that the centre is narrower. So a proper venturi in the true sense... it still has a bellmouth though.

When I was getting the 24G set up is when I became aware of this inconvenience not sure if you can modify other jets seem to recall the thread is different and shorter. See what pilot jets you can find for T5 24G I would be interested.

I'm confused ... I get that the intake is straight on an SI. But what does the that CNC'd Pinasco piece do that patrick's bellmouth doesn't? Does Pinasco taper the throat of the carb?

I think any gained performance is due mostly to a lighter wallet and therefore higher power-to-weight ratio.

If both of those 26/26 carbs are for non-auto lube, why not just go after a better design, such as Dellorto PHBL 25?

https://www.sip-scootershop.com/en/products/carburettor+dellorto+phbl+25_41000000

Ha - now you are just taunting me!

Truth - the whole PHBL ABCDEFG carb thing scares me.
I have reached the point of minor competency with the SI's.
I almost know what I am doing.
Just can't jump in to the alphabet side drafts and their sharper needles and clipped pins on the third notch stuff. Bogles my mind.

Of course - I could take that 26/26 and make a JB weld tapered sleeve so it was a 24/26 and then put a bell mouth on it! How hard could that be?

26/26E and VRX will work. Not so sure about anything else (G with jets or sidedraft with VBB panels).

The SI carb sits right on top of the crankshaft ie. whole inlet manifold is about 3/4 inch long. Once the carb is moved away from the crankshaft and the inlet manifold is way longer, the now remote carb has to be a bit bigger to be the same as the SI.
I think a 26/26 (properly set up) is about the same in performance as a PHBH28. Expect a few opinions about this.

Thanks gents.
Always interested in the insights.
Travel today - so ripped down the engine over the weekend.
Have to say: looked nicely built.
Italian crank and rod - look to be Piagio.
FAG bearings in the case are as new - tho I will renew since I am there.
Cogs are in nice shape.
No peening, no weird wires or clips, no card stock shims.
This motor was nicely built.

Unfortunately, this drive shaft is well and truly done.
Jack - you will be pleased to know - it looks even worse when out. Hahahah. I have no idea how it managed to get me around so well for so long.

I did a quick look at inlet timing and got the following unofficial numbers.
You can see some slight variation in my measures - but close enough for quick look

Inlet opens at 0 degrees
rotating clockwise until inlet is fully closed occurs at = 199.5
continue to rotate until piston top gets to top of transfer port occurs at = 141.3


TDC = 0 degrees
Rotating crank clockwise I get the following in this order:
Intake closes at 299.5
Piston top closes transfers at 121.5
Inlet opens at 100
Inlet shuts at 300
Transfers open at 240.5
Transfers close at 121.5 and above numbers cycle through again.

(Keep in mind I have 1.7 base gaskets in place and I will also be going to a 60MM crank)

Question - perhaps Sime or Jack wanna weigh in on.
Now looking at my two crank options - am I still safe with the Pinasco or do I need to be more conservative and go Mazz for timings.

Pinasco advertised timing open and closed (I think) 123/6
Mazz crank same 112/10

this gonna be a fast sidecar

Gents - in Germany and plan to poke my head in to SC and SIP this week.
Could use some techno expertise.

Looked back at my numbers ( can hardly remember how I figured this all out). After I took 1.75 mm off cylinder, and assembled, this is where the motor is currently with the stock 57mm crank: I'm not really clear on how to proceed.
If I put the 60mm crank in, is the game to then add 1.5mm to my packer to maintain the .2 PBT and .96 squish?

That would leave me with much higher timing:
131.68/180.87/24.59
Have I made wrong assumption that additional 1.5 base packer will maintain distance measured from top of cyl. to top of ports - after change to 60mm crank?

Can anyone outline the play here?
Lil confused.

Thanks!
-CM

Call me crazy, but I'm thinking you're going to want to put the additional 1.5mm gasket at the head, not under the cylinder.

SoCal - thanks for weighing in!
I was in the middle of making my shopping list when I realized I didn't know wtf I was doing.
editors note: This is not an uncommon state of being.

Hadn't even considered a head gasket.
Plugging in a 1.5 head gasket would give me:
124/175/25.4

Clearly this is more appropriate direction.
I can trade a bit of squish to lower that if I want to.
E.g. 2mm head gasket would instead give me:
122/173/25.7

Not sure best target.
Chandlerman suggested previously that he thought I would find the timings low with prior timing (119/174/27)

Bike was a joy to drive with that timing - but maybe there was more optimizations to be had. In the end, if it gets more power in upper band - that's fine - as long as it doesn't drop power in lower band. Of course - more power all the way through - would be great!

Gents - one more hot one.
The is the shaft that goes inside the xmas tree gear cogs.
What ever that is called.

One thing I can't quite fathom.
Why is there a key slot at near the threaded end?
I am fairly sure there was no key that goes here - so is this shaft from a different motor? Is there supposed to be a key slot on this?

Thanks!
-CM