Modern Vespa

What do we call the piece at the bottom of a cylinder that slides into the mouth of the case?

attached is the 190

Is it worth it to go 190cc displacement on a Pinasco vs the more common 177cc?

and how do I know if the barrel will fit in my Sprint casing?

It will fit into your Sprint cases, but you will have to TIG weld up your cases for sure.

Why would I need to weld? I know the case gaskets already exist.

Sides transfers of the cylinder will extended beyond the gasket surface of the Sprint cases. I could be wrong, but don't think so at this time.

Is there another forum post on this instance?

That bit (that's broken off in this pic) is the SKIRT

Always under the impression it's called a spigot.

And most likely you'll need to weld your cases like Gickspeed mentioned

TIG weld. . then mill the gasket surface.

Sprint cases are most likely like VNB type, just not enough gasket surface to seal the cylinder.

Now you could machine the bottom of the cylinder and use a thick cylinder gasket to seal (and pray like hell). .. but i would just do it the other way-

I'd say it's not, for the reasons already outlined above. What are you trying to achieve by fitting this kit?

You can get 17-18 HP out of a SprintV motor with a BGM 177 or VMC 177 and various other changes (correct exhaust choice, 24/24 carb, 60mm cut crank, setting port timing correctly, maybe adding a variable timing ignition to the mix). You'll want to do a little porting of the cases, but there's not a lot of meat to work with, so you'll need to either add metal and/or be veeeeery careful with the dremel.

Are you looking for more top end? Faster off the line? Bragging rights?

And, maybe most importantly, are you up to the task at hand? There's a lot more to tuning than slapping on go-fast parts and having your bike to be magically faster.

Fill us in on some more details and we can provide better guidance on how you can achieve your goal.

I would also urge you to check the crankshaft. Is it the early narrow taper or the later (and stronger) P series type? This will determine your choice of crank and how far you want to go with the tuning. If narrow taper, I would personally go with 177cc (57mm stroke), but if it's the later type, I would go 190cc (60mm stroke). There are some great P series crankshafts out there.

You can get a P-series cone 60mm crank that'll fit the Sprint cases, too. That's what I run in my SprintV motor.

Isn't a Pinasco "190" just a 177 cc jug with a 60 mm crank and a bottom spacer? You can stroke any 177 out to a 187 that way. Usually worth about 1 extra horsepower. Not trivial when you're starting at only 16-17 horsepower to begin with, but not exactly a game-changer either.

It's also $125 more than the BGM or VMC, which would almost pay for the new crank. Yes, 63mm bore, so effectively a 177 with a cheap marketing stunt layered on, IMO, even if the quality of the kit itself is good.

I would just do the BGM.

now circling back to gasket surface. I took a BGM gasket and put it on a set of VNB cases that i modified for a DR cylinder; the side transfers not changed. There is not enough material on the case to seal even with the smaller transfers of the BGM.

Are later Sprint or SprintV cases any different? I don't think so but i will stand corrected if so.

I have a BGM with the gates cut out on my later (1976) SprintV motor. It fits, but I was grinding *very* carefully to make that happen without leaks, and was sweating the first pressure test after I fitted it just the same.

Sprint cases are most likely like VNB type, just not enough gasket surface to seal the cylinder.....

Is there a photo gallery of all the vintage Vespa case mouths to compare and understand them?

I would reconsider. There are way better kits out there…

Pinasco cheese piston…

There are a few non Pinasco kits that look good. This parmakit is designed to slip on 2 port Sprint cases.
Ideal if you want a lot faster but still want it reversible.
https://www.sip-scootershop.com/en/product/racing-cylinder-parmakit-sprint-gt-super-177-cc_80527000

Jack221, what are the brown and green paper gaskets, I also see 2 metal gaskets.

As an aluminum welder…
I'm a fan of JB weld as a solution for lack of material!

Is it permanent?
Of course not - but neither is the Nikasil cylinder…

These kits are awesome upgrades.
Things will wear.
My experience: you can get 4K miles of pretty fresh use.
More if u don't mind it getting a little tired from optimal.

JB weld is good for that same sort of mileage.

I wouldn't hesitate to install a BGM on sprint cases with a bit of jb weld to help create a larger sealing surface.
Clean it.
Score it.
Clean it again.
And poor it on.

Plenty of joy to be had.
Just understand that it might not go 10k miles before a redo.

All for adjusting squish to the crank, even if your crank is 60mm by the looks of it.

CM, I have one of those 'hybrid' 60mm cranks in my VBC motor + BGM 177, but I've never been happy with it. I was glad of the P series taper, as I could use a better ignition, but it always ran lumpy, as if it wasn't balanced, and I'm sure the crank timing was not that much more than stock. Did you cut 'n flow yours further, or just use it OOTB?

What about the Malossi 177 for only $269 https://www.scooterwest.com/malossi-166-cc-cylinder-kit-for-vespa-p125x-px150-stella-m3114935-m314093.html

and it's close to me as Im on the West Coast. Scooter fit only says Sprint Veloce, fitting it to my Sprint could I leave my stock 57mm crank and will it have any problems on the gasket surface for sealing?

Also this one for $248

https://www.sip-scootershop.com/en/product/racing-cylinder-vmc-super-g-177-cc-7-travasi_84140300

Where there is the 3rd boost port what if I mount it to my Sprint case and leave it not dremeled out?

Question is VMC vs Malossi.

if you don't have the 3rd port or want to cut the 3rd port or unable to cut a 3rd port then you should be looking at the 2 port options, especially with the 57mm crank.

if you DO have the 3rd port all figured out there are a whole mess of kits that fit without worrying about welding up the cases

I have been happy with mine. It was already cut some, I just opened up the intake to get the timing I wanted and it runs smoothly.

I'm getting over 17 HP with it and a BGM177. I can't complain about that.

As Jack221 said this 177cc kit will slip right onto my Sprint case. Is the case able to hold this one?

https://www.sip-scootershop.com/en/product/racing-cylinder-parmakit-sprint-gt-super-177-cc_80527000

I *know* this one fits https://www.sip-scootershop.com/en/product/racing-cylinder-pinasco-177-cc_80510000 without any modification. I mean, besides a very light gasket match to the case, which honestly you can probably get away with not doing.

the parma will fit, but the devil in the details is whether or not you'll need to add material to make the base seal, and if you have the meat on the cases to match the ports.

but this circles back to you saying sprint. does this have a 3rd port? is the meat in the cases to cut a 3rd port? do you even want a 3rd port?

this is important because you can't put a 2 port cylinder on a 3 port motor. also, 3 port cylinders are much more plentiful than 2 port so that opens a lot of doors.

I'll get the photo of mine tomorrow to see what I have.

dont
piston is terrible

simply forget all yellow cylinder kits.
and just be happy.

There's the engine

Definitely a two-port motor. Go with the Pinasco 177. I initially said Parmakit, but you don't have the sealing surface.

I have some more questions, though. Can we see some more pictures of the bike?

(I'm looking at the cowl pin hole, for anyone else who's now thinking what I'm thinking...)

get the two port kit. I'd recommend the pinasco one that I linked earlier. https://www.sip-scootershop.com/en/product/racing-cylinder-pinasco-177-cc_80510000

the parma is only $50 more, but may present some difficulty on installation for you where as the pinasco is plug and play.

now that you've brought it to my attention, yes. the frame grommets are a tell tale sign along with the cowl hook...

*spidey senses triggered*

The 2 port Pinasco kit is upping the displacement but does it offer any port increase (of the two ports) compared to the stock 150 cylinder?

I can take more photos, what do you want to see? chandlerman