Modern Vespa

NSM is a great place for a classic scooter addict. Wealth of knowledge, and a team of some great folks too.

Which is why I'm gonna do the noob thing, and ask something that can probably be found in the past posts. I apologise.

I promise you, there is a method to my madness. I'm just a tad pressed for time, as I'm preparing to travel for a few months. But in the course of travel, I want to gather and bring some goodies back with me. Mainly some Vespa performance parts. 😁

Your hands on experience needed here, please. What's the most extreme modification that you've done to your 125/150 motor? Whatever you think is extreme, is welcome in this post. I only ask you for the emphasis on PX "small" block.

To that name, fire away please.
🛵💨💥

Welded a self made reedvalve manifold to pair of cases so that there was no air leak and the oversize carb hung out tbe back of the engine

Impressive! Carb was facing aft? No problems with low pressure developing behind it at speed?

None at all

One more for you, welded it yourself?

No sadly, I cut, shaped and formed the aluminium box section to the shape ir needed, then farmed that out to someone with the equipment

I did however spend a while afterwards with a sheet of emery paper on a .metal block making it flat and true again.

(Over zealous welding at the crankcase end)

Oh and another one for you

Welded the crank - nothing unusual there.


This wasn't my work though

Bloke ground the web/cheeks down to almost nothing to make it as light as possible and fully low pressure crankcase.. went like stink.... vibrations wasn't THAT bad either to say it was unbalanced... but my heck did it rev and accelerate

Love me some 150 tuning

How many dollars are you wanting to throw at this? You can go with something like what I've built in my GL. The build thread on that is almost six pages long at this point and involves three explosions (one gearbox, two which I think were too-small cylinder stud holes).

- Malossi cases
- Quattrini M1XL (direct intake reed, rear-facing carb)
- Side draft carb; pick your poison
- 60mm 110mm rod full circle crank
- Vape variable ignition
- Malossi Box, later a PipeDesign Cobra 2
- All the supporting gearbox & suspension bits

Total project cost was about $500. Just ask my wife.

It's not as terrifying as my Smallframe, but also not nearly as loud, and loads of torque, even before it gets on the pipe and things get wild.

Just finished reading the post, damn... you have a lot of patience. 👍🏻

I thought about the m1xl, but your story definitely leaves me not regretting giving up on that idea. Thanks for sharing

https://www.scooter-center.com/en/adapter-plate-set-incl-crankshaftcylinder-special-for-fitting-polinimalossi-210-cylinders-685mm-engine-cases-px80-px125-px150-cosa125-cosa150-sprint-veloce150-vlb1t-294260-gtr125-vnl2t-145901-super150-vbc1t-412374/p-44926.html

or

https://www.scooter-center.com/en/drilling-template-incl-drill-sleeve-drilling-pattern-px200-cylinder-stud-bolt-px80-150-motor-housing-used-for-mounting-quattrini-232244-cylinder-72mm-px80-150-motor-housing/p-44928.html

+

https://www.scooter-center.com/en/cylinder-quattrini-m244-72mm-stroke60mm-con-rod-lenght126mm-244-vespa-rally200-px200-cosa200-special-crankshaft-necessary/p-3909.html

=

You got me there, this is exactly what I've been thinking about. I just didn't know someone had made the adapter already. And it's so affordable it's not even worth making. 😁
Edit: spoke too soon, it's just a drilling adapter. 🤦🏻‍♂️ I thought it was an adapter between the small block and big block cylinder, to match the bolt pattern. Something that BFA offers in their kits for small engines (at an exuberantly high cost, IMO).

I liked the Quattrini m244, but lately I'm leaning towards VNC Explorer. But I would like a reed setup, which Explorer doesn't support (I think).

Good stuff Ginch, thanks. 👍🏻

You're changing up your requirements here. If you want a kitted 200, get some 200 cases and build on those unless you have some sort of regulatory requirements this gets you around.

As to running a reed, you can either buy natively reeded cases, e.g. LML/Stella/Star or Malossi, or just hog out the the rotary pad and flow the intake. Combine that with a reed block, intake manifold and side draft carb of choice.

https://www.sip-scootershop.com/en/product/reed-valve-block-tassinari-vforce-4-for-yamaha-rd350_40312120

and

https://www.sip-scootershop.com/en/product/intake-manifold-mrp-35mm-long-intake-sealing-surface-for-vespa-125-vnb-ts-150-vba-super-rally-px80-200-pe-lusso-t5-cosa_22159443

I feel compelled to ask at this point how many motors you've built. You're new here, so I don't have a good feel for your builder skills, and what you're talking about is not Tuning For Beginners, so I want to make sure we're not encouraging you to take on a project that's going to wind up blown up on the side of the road.

Engine casings being the core of any build, but as it turns out, also a bureaucratic nightmare where I hail from. Here's the catch, you're not legally allowed to change engine casing, unless it's the same make and model. No upgrades, clever tricks, and such. Just a like-for-like LML PX150 clone, thank you very much. Because god forbid anyone tampers with the sacred aluminium lump on a scooter, angels would have fallen from the heaven... 🙄

Now, I do understand that aftermarket casings are the sensible choice when building a tuned engine. If not for their improved strength and durability, then at least for the extra material they carry in the need-to-have areas. Alas, nothing in my country is about sense. So I need to keep things street legal, in a place where rules appear to be written by someone who once heard about engines from a friend of a friend who's father was sharing a bus ride to work alongside a cleaner who worked at the metal foundry... 😐

To make things worse, you can replace the casings. Legally that is. You just need to present your entire vehicle to the police, so they can solemnly assess whether your original casing is "beyond repair." If their wives gave them a kiss on the way out of the door in the morning, and the moon is in the correct phase, you may get permission to replace the casing with a blank. That blank must then be stamped with a serial number, but only by someone on the Official List of People With Hammers, as approved by the authorities. 😄

Not to mention potential years in the making. Someone asked about costs?

So, with all that in mind, I don't think I'm changing requirements here. The goal remains to extract around 250cc from the original small block. Mad? Possibly. Doable? I believe so. Welding and machining are relatively inexpensive around here, and when the regulations already resemble a Monty Python sketch, what's a little alloy nip'n'tuck between friends? 😉

As far as credentials go... I've been lurking for two years, mostly plotting. I think I watched every SIP & FMP youtube video there is, before I bought mine earlier this year. So, no Vespa specific experience here, but I've got years (decades?) under the belt with cars and motorcycles, in all aspects. Also spent couple of years competing in an endurance event, based around a 50cc moped. Rules were "kind of strict" and "completely open" at the same time.

I've had worse ideas in life, I'm sure. I think I'll be fine. Not like you're gonna push me into something I don't want to participate in. I actually think the opposite, the more one knows, the better the mistake one makes. 😁

If aluminium and machining are cheap by you then i suggest the following

Machine the spigot to accept a 200 style cylinder stud too

Machine down the Xmas tree spindle to 2mm thinner and have the corresponding hole welded and machined to suit.
That will address the weakest spot on a vespa engine

Then..... fit whatever crank stroke length you want assuming you can machine the crank area to accept and go for broke 😀

Interesting proposition, indeed... 🤔 I'm a bit weak in that area, can you school me please? What exactly needs to be machined in the crank area?

Cheers mate

Crank area machining
Some longer stroke cranks, require some metal removing to allow the longer stroke crank to fit... think anything past a 60mm stoke

Also to go read you would need to machine out the sealing lip.. its possible to do with a dremel bit cleaner with a machine to do the work for you.

The weak area around the Xmas tree spindle is the thin area between the clutch housing seating snd the spindle itself. Tuned motors or badly tightened Xmas tree shaft can cause a crack that will spread and write your casings off.

I get the Christmas tree modification, it's a good idea, I like it. It's the crank area that I'm not familiar with. We're talking about the area where connecting rod may come into contact with casings? Or something else? Picture would go a long way... 😂

Correct!

Nah I think the adaptor fits in the moderately extreme zone.

Rikko yes it's a "drilling adaptor", but reading it again I'm thinking that once you've drilled the new stud holes (and welded to suit), you can fit the new 200 cylinder directly to the case. Re-read yourself and tell me if you also think that's what they are saying?

That would fit well with your access to relatively inexpensive welding. Otherwise there's the first link to a fairly simple bolt-on job.

So where are you in the world? Thailand?
I was thinking that if you happened to obtain a set of original 200 cases for instance, and the numbers on them happened to change ever so slightly to what is in your current scooter, it would bypass the policemen and their relatives. I haven't heard of that method, have you done it? Does the shaft have to be re-hardened afterwards? The shaft also has a keyway (for want of a better word) for that tabbed holding washer to fit, would that be an issue do you think?
The only other method I could think of to beef up that area was a Crazy Monkey device, can't remember what they called it now.

Pictures - what Gravelrash is talking about is what they refer to (for some reason I don't understand) as "spindling". The longer stroke cranks have bigger crank webs and need a little extra room to gain clearance in the case. It can be done with a router if necessary - check out Stuart's method here - Building a "Boss Hog" engine (Post 2468249)

I didn't mean to downplay the benefit which adaptor brings. I was just a tad euforic, and then deflated when I realised that it was not what I initially thought it was.

In fact, my original thoughts were to weld in areas where small block is weak. So, in such scenario adapter can help locating the new stud holes. Adapter however is not crucial for me to achieve positioning, simply because I can drill holes on my drill press (press drill?) precisely enough to warrant a proper fitment of the new cylinder. Template would be the cylinder base gasket. "Clocking" of the cylinder would be decided on, based on crank/piston/ports relative location.

Later, I did continue researching and found that the adaptor plate does exist. Reportedly, it was concocted by a guy called Geoff from J&G 2% Vespa Tuning. I also found a guy from Arzente Motori talking about the plate, but as I don't speak a lick of Spanish, I got zero of what he said.

Unfortunately, I could not find one plate being sold without the crank. I don't particularly care to fit BGM shaft which is included in the kit. It's also 125mm rod on it, which is 1mm short of recommended 126mm for m244 (in case I choose to go Quattrini way). It probably wouldn't even fit with m244 cylinder.
Edit: Aaah, FFS, how did I miss the link twice now?!

I'm located in Serbia btw. We had LML distribution back in the day, it was some shady trade agreement with India, we were exporting tractors (Massey Ferguson derivative called IMT) and importing LML Vespas. Clone wars if you like, but without the flashiness of Empire or Republic. There was no Piaggio dealership locally, so whatever PX200 units are available for sale today, they are imports which happened over time. Since LML did not make anything but small block PX engine, it's really really hard to get anything from a 200, short of buying from abroad. There were some Cosa's broken down for spares, and even one casing half from a 200, but most of them are actually 125.

I did find a new half of 200 case in Italy, relatively affordable too. So I posted to see what are the chances of two unpaired cases matching within tolerance. But, a half of Italian casting machined post 2k and an half of Indian casting machined pre 2k don't leave much confidence to proceed. 😁 I would still need to relocate the two Indian-half based studs. Overall, decided it's not the route to follow. A mistake? Perhaps. 🤷🏻‍♂️ Time will tell.

Off to seeing what Boss Hog engine is all about...
Thanks 👍🏻

That's a cool trick, I have a router that could come handy for this type of work.



Re. the spindling, perhaps people are not familiar with the term fly-cutting. 😁

Only saw this now 🙄
That's ballsy I'd say. Any word on how long it lasted?

5 years - my son used to ride the engine every day to work and back.. it ate its way through other engine compartments as he had only two throttle positions he liked to labour. Open and wide open

But the crank... thousands of miles

It's just a carbon copy of a spindle Piaggio made

They made a rhin one for the earliest models sprint etc
A thin and thick for the intermediate models. The kind one would need if using a late gearbox in a Rally or similar

And the "thick one" we all are.familiar with on the Later EFL and LML engines. Turning it down oneself is the lower coat option to finding the in-between/crossover one.

Hardening again? Doesn't need it, but I can't see the harm in doing it.
Piaggio never hardened there's. One improvement i could suggest is to machine a couple of flats on the opposite end so it can be held whilst the clutch side is torqued down to a decent spec

When they made the 200 cases (derived from the GS160 originally), they didn't 'strengthen' the case. Any weaknesses tend to be applicable to 150 and 200 cases. Probably. That's how Geoff started off many years ago with a conversion of an LML case. See below. Btw nothing wrong with LML cases, a good shortcut to reed. Also, somewhere on the forum there are some fairly precise drawings of the case/stud setout of 150 and 200 cases. Yeah you're actually stuck with stock positioning, otherwise you're going to run into issues of ports, ring pegs etc not aligning. I guess you could say you have wiggle room. That was it in my first link. Geoff is a friend of a friend. He's sure got the bug. Unfortunately he told me that he doesn't make anything from the SCK sales of his development. He just gave them the right to produce it, which I thought was a bit sad.

Got a link to the Arzente Motori thing? An Italian place makes an adaptor for sale by itself. Can't recall which place right now. Given your access to cheap welding I think the adaptor is not necessary. Then you could use a Quattrini 126mm crank or an Uncle Tom 127mm.

Coming back to the Explorer, there is nothing that says you can't or shouldn't use it with a reed valve.

Some nice roads in Serbia?

Ah ok, so just a mix and match for the correct fitment both ends then? I put an EFL into a VBC case and that shaft was key to the conversion. Cheers.

Spot on. Easier ro get one machined than try source a replacement I think

Here's the specific video that I was mentioning:
https://www.facebook.com/share/v/1Cr6VhBTzt/

Too bad about Geoff. Perhaps he should give his authorisation to other makers too, so that there is competition in the market. 😁

Re. the reed, I failed to specify that my aim is for direct reed intake. If I was to go Explorer way, then I'd probably stick to rotary induction. I just dislike the rotary pad to crank gap requirement, and the possibility for the pad to somehow magically wear off. 🤔

Serbia had some roads. Problem is because of corruption all over, roads don't last as long as they should. I've been off the bike for 5 years now, it's anyone's guess of the condition of these roads today. Traditionally, there were some nice routes to ride on. You would start in the capital, and venture south. If you really pushed it, it's possible to do a 1000km trip in a day (roundtrip from capital), almost without a piece of straight road. Happy to take anyone on a tour, once I have Frankendrak complete and shaken down. You'd have to bring your own Vespa though. 😁

Stuart was very kind to have sent me the template he used on his Malossi casings. But the cylinder stud pattern would be very nice to have indeed. Gotta look for it now...

Thanks

Edit: found it -> https://modernvespa.com/forum/topic155058#2174738

If you maintain the rotary pad and then try to offer in a 200 crank meant for rotary induction, there are complications.

You will either need to assemble a special crank to accommodate your need.

Rework an existing crank to remove the lip found on a 200 rotary crank

Not fly cut the crankase - you will lose rotary induction.

Your best all round option is to go reedvalve so you can modify the crankcase to accept the crank if choice.

If you want to keep a standard presentation carburetor, you could modify an LML reedblock to sit under the carb box.

I believe LTH made such an off the shelf item and DR also make one

See, this is the knowledge I lack. I'm happy to have joined the NSM. 😊

So, to sum it up, 200 crank - no rotary pad. Perfect! I hate it anyway. 😁

As far as carburation goes, 28 PWK is on order, along full set of jets, needles and atomisers. I opted for a PWK clone, let's see how much of a mistake that was. 🤞

Be sure you purchase a crank without the lip

Or you will be machining it off

SI carb is beyond your power goals anyway. If you want a smooth riding road scooter, the SI carb is limited to not much over 20bhp. Can get more power out of the SI carb but they end up spluttery at low rpm with the associated poor economy.
So, side draft carb, with reed block is the way to go.

Thanks for the video. Interesting. It came up with english subtitles for me?
Yes Stuart is one of the nicest guys, pity he lives 2000km from me. What do you mean by this? Direct to the cylinder?

Subtitles?! 😂 I better try again then... Edit: It did come up with subs now... 🙄

2000km sounds like a nice distance to cover on a Vespa. If you average 200clicks a day, and you meet in the middle, that's 5 days one way.

I actually meant direct to cylinder, yes.

We've ridden up there a couple of times over a week to do the Mille (1000km in two days). We did find that we were a very long way from an exhaust on our last trip when the pipe pulled out of the body. 4 days of riding with a straight out exhaust was a chore. Lucky for me it wasn't mine. You could go straight to a Quattrini 172 which avoids case work and is a very good cylinder in it's own right. Much easier build.
You appear to be looking for a challenge though, and the Quattrini 244 can do that too. The casting is already made to enable that, with some work of course. Not sure but the manifold in these pics is probably the same one as fitted to the 172. Jack or Chandlerman will be able to confirm.

You got me there, challenge is being looked for.

So, if I'm judging the photos correctly, I would have to cut into the cylinder lining to open the passage. Isn't that a no-no with nikasil lining?

Cutting nicasil is possible, just no room for error.

https://www.sip-scootershop.com/en/product/racing-cylinder-quattrini-m1xl-11-172-cc-for-vespa-125-gtr-2-ts-150-sprint-2-v-super-2-px125-150-pe-lusso-cosa_15046100

This is the M1XL kit with the inlet cut for you. Easiest 25bhp ever added to a 125 block.

I used to think that the direct intake was a great idea because it goes straight in. Eventually realised (duh) that it has to go around through the crankcase first. I figured then that the intake into the case didn't look so bad after all. In the end I'm not sure of the advantage of one over the other, assuming the same size reed.