Modern Vespa

So a new guy got my number and is asking for me to build him a SF motor for his 74 Primavera 125. Owner is a big guy 240 lb (108 kilos). Wants power and still reliability on a middle of the road budget. Wants to keep the 19 carb to save money but it's negotiable. Going to go Vape on the ignition.

What do you guys recommend? Malossi? VMC? Polini?

Big boys club on a budget- I have done just that on the my first VMC135 running the 19.19. some pics for your viewing.

I would think that transmission gearing would be just as critical as a cylinder kit for a clydesdale rider.

Yeah I'd look into the carb and primary before ignition (unless the ignition is DOA)

But to be honest… there's a snowball effect… clutch and gears probably need to be swapped out.

agree. gets into parts creep territory. simply installing a cylinder kit is not going to be the end of it.

Given that I'm a 230 lb guy, I'd say that the bigger issue (like the bigger rider) is going to be which Smallie cylinder produces the most torque.

Look at the Egig 170 with a pipe that favors earlier power, maybe the matching Egig Unisex. Plus the Egig crank, so that may be getting beyond the customer's budget, but it would absolutely give him what he needs on a relative budget.

If the gearing needs tweaking, though, that's going to be a new primary shaft, which is $125-175, depending on what you go with. I don't think that'll be necessary, though.

Scoots here and starting the shopping list. I like Gicks VMC 135 idea. The aluminum version is on sale at SIP.

@Gick- what are you planning on for gearing? Leaving it stock or swapping?

went 27/69.

https://www.sip-scootershop.com/en/product/gearbox-27-69-256-teeth-sip-sport_16330000

I'd tell the big guy to get a big guy bike. Small frame engines need high revs, clutch slip to get moving, which goes against the problem of breaking stiction. That problem is more easily overcome by large displacement, lower rpm and bigger torque engines. OF COURSE, when money is no object a small displacement 125cc can make big power even for oversized load, but that is not practical or pragmatic for anyone but those obsessed with efficiency.

That's what I would tell 75% of vespa riders I know. Just buy a motorcycle and get it over with. They want something that can go two up on the freeway for 2 hours with disc brakes and an air ride suspension for $500. Ain't gonna happen.

That said, this guy realizes what he's got and has been realistic of the coming work. He also knows my time costs which has been a nice change of pace.

Their expectation of KTM performance out of a Vespa is always a short coming. they can still dream, i guess. they are usually short time Vespa owners.

The other expectation is not putting more money in it then it's worth.

Welcome to power sports.

Vape was installed and all lights working now. Stator wires were toast and it was only a matter of time before he lost spark too. Owner likes me and my work and has given me the go ahead for whatever it needs. I'm thinking VMC aluminum cylinder with a 25mm carb and clutch. Keeping the vape and Polini pipe.

Gick, the 27/69 combo is "in arrival" at SIP and might be a while. Penny on your thoughts for the next best in stock combo for a higher top speed for a big guy?

other manufactures make the 27/69.

They sure do! Scooterhelp gearing chart looks promising

It's less about the speed than the motor's ability to drive it. Does it produce enough horsepower at those RPM's to overcome resistance?

Parts are ordered and it'll be a few weeks. I'm curious to ask, has anyone used the VMC or Malossi short 4th input shafts? I used a DRT once and it was a mess! Taper was bad on it and the clutch wouldn't hold.

Just thinking in case the owner doesn't like the jump from third to fourth.

I have the long 2nd, short 4th Malossi in my Smallie. It went in no issues. Brought the start of power in 4th down so I'm not lugging it at 50 MPH and made 2nd almost long enough to be usable.

SoCal put a DRT (I think) primary in Red and it went...not as well...

I used DRT short 4th in my Primavera with no issues and no shimming.

I'm not a small guy too, almost 100 kg.
I have this SIP(VMC) kit on my PK.
Paired with SHBC 20L, racing crankshaft, SIP 27/69 and short 4th VMC gear tree is perfect commuter that easily can sits 85-90 km/h out of town and have near 100 km/h top speed.
One of advantages that it is not need to cut and deck cases.
VMC also have Kappa - 135cc alu that also not needed case modifying.

On my Special there is also VMC short 4th. And it have issue with seating in the bearing. I was need to use Loctite to make it hold there. AFAIK it is problem of early made x-mas trees. Two years later I bought next one for my PK and it haven't this problem. You can choose any other.

Motors dropped! Clutchside and rear seals were installed backwards, gaskets inverted, kickstart buffers disintegrating etc. Amazing it actually ran! I'll pressure wash the cases tomorrow and hopefully it'll be off for welding Monday.

The owner is stoked and found some money and wants to upgrade the pipe. Anybody ever try the VMC Evo pipe? Egig Performance Unisex 1.5mm from SIP?

Unisex is good, I'm running that… not the 1.5mm but if you have deep pockets… I'd go for it.

Owner is dead set on Egig Performance. Wants that look. He's paying so I'll make it work! Anyone know how much of the battery box to cut out?

I ordered the Polini 27/69 combo Sip# P2021217 as I figured it's middle of the road price wise and hopefully up to the task.

Cases are at the welders for the next two weeks.

The VMC exhaust looks great !! No idea about the sound or perf but it looks like serious construction !

Wasn't it possible to swap the engine for a px200 and maybe mod it for a bit more low end torque knowing the weight of the owner

Back on the project. Egig Mamba made it just in time. Spending the weekend cutting.

Anyone know how much I should open up the intake?

Manifold matches the inlet and uses bolts instead of studs. Doesn't give me a warm and happy feeling 🫤

You can get longer studs… the Malossi manifold I have, the 2 studs are 2 different stud lengths.

Wow big transfers

Just enough to match them, and arguably don't even need to do that. I've recently come around to the reality that the port openings into the cylinder are the bottleneck, so other porting is wasted.

I've got the Malossi 135 sport kit on my v90, stock 19mm carb, Gianelli pipe. I'm 6'3, 250#. Bike has no problem doing 50+ Mph, would get there a lot quicker if I'd replace the clutch.
I think it'd be happier if I went back to my Polini snail pipe. The Gianelli seems to hit too high, but it looks cool and sounds evil, lol.
I'm sure I could get more top end with some gear changes but my height on a smallie makes higher speeds sketchy.
I have an 80mph Stella if I need more speed. It is funny that I have a 70cc Moby moped that'll also go over 50, it just needs a lot more room to get there. Just sold my big OT bike as I didn't have much need for 100+ and after my wreck wifey feels better if I stay off the highway.

If for general fast road use, at least 180 degrees. If there is the metal 190.

First time cutting on a smallframe and hopefully the last! It felt sacrilegious cutting apart a good frame but oh well, the damage is done (literally). Only have one small spot I want to get welded back just so it doesn't snap on the owner.

Question for anyone watching, are the curves radius' enough? Don't want cracks to form down the line. See anything else wrong that needs touch up before I spray paint the steel?

I couldn't do it, myself. I know it's just metal, but I feel like you do mjrally.

It kept me on a simple polini kidney pipe in my smallframe, but at least I could look myself in the mirror.

Have you made sure it clears when the shock is fully compressed? That cut at the bottom looks like it's going to rub when compressed.

Question for anyone watching, are the curves radius' enough? Don't want cracks to form down the line. See anything else wrong that needs touch up before I spray paint the steel?
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I don't like the one at the top right corner. I get a little anal on stuff like this and smooth all the edges. The wavy lines are cosmetic but I tend to straighten them out too. Like C Man said, make double sure everything is good at full travel of the suspension.

Funny you should mention that, now I've found it's hitting where the spring holds both exhaust joints together. Back to cutting

You owe Chandler a beer 🍺! 🤣

For sure! I've got some warm ones sitting outside in a cooler from the last party we had.

So long as it's also really shitty beer, I'm good. I'm a scooterist, after all.

Clearance at the springs, but now there's contact on the bottom right. Poor can is getting all scratched up. For someone reading this in the future, mask up the can or buy a second one so you can swap when everything's correct!!

not much left in there to remove....