Modern Vespa

Muriatic acid will take that aluminum off the barrel like nothin', then a quick hone and the new piston and you're good-to-go.

how do you apply the acid? I assume touching it and or getting it in your eye is not recommended....

I dipped a paper towel in the acid and just kind of wrung it out onto the smear in the barrel, but you could use a syringe or spoon it on there or something, too. Just don't use an aluminum spoon

It's a malossi 166?
If so, it's probably the "0" piston, unless it's been rebored. You can select the correct variant from this link:
https://www.sip-scootershop.com/en/product/piston-malossi-0-139-166-cc_34161700


Just use your digital calipers to measure the approximate bore from the deck. Technically you are supposed to measure a certain distance from cudgeon pin. A measurement will give you a better understanding if you need an oversized piston or not.

yes malossi 166, appears to be standard, with bore coming in right at 61ish (slightly smaller according to my calipers)

Anyone have a spare piston?

I think they have markings on the piston crown that should tell you if it's oversized or not. Scrape the carbon off and see if it's got numbers on it.

yeah smart call, will do

So no markings, just a dot on the exhaust side.

Questions:
The auto lube hole, plug with jb weld? This is premix no matter where it goes.

How do I cover the starter hole?

Is the crank taper the same, can i bring my px flywheel, stator, and Cdi over to this bike?

Someone sells a metal plug for the auto lube.

https://www.scootermercato.com/Scooter-Parts/Carb-Boxes-and-Covers/OILPLUG

And you can get a rubber plug for auto start hole. I actually just got one recently from mercato.

https://www.scootermercato.com/Scooter-Parts/Plugs/483859_2

So where do we buy the Stella specific seals and parts like reeds, etc? I don’t see Mercato showing bearing and seal kits for Stella

The reeds are obviously LML/Stella-specific, but the bearings and seals are the same as later PX's.

Any of the Internet Usual Suspects should have them all, and Scooterworks was the original importer, so they should have the reeds if you need them. If you're sticking with the OG metal reed, that thing never wears out. If you're replacing it with fiberglass, all the Usual Suspects will also have that, or you can cut your own, which I've never done but is allegedly not terribly difficult.

Gotcha! Thanks.

geesh. now I feel like a real jerk! fwiw, that did come in running, so there's the most minor of condolences, and a bit of a testament to the durability of those motors.

I'll echo others. clean and lightly hone the barrel and go next over.

you can but I wouldn't. keep everything the same same. less problems down the line.

There’s a ton of wiring to deal with if I try to run the Stella cdi, etc. Where to mount it in the px, no mounting for the coil, etc. If I KNEW them to be good components, maybe. But as is….

I’m betting I can trade them for stock px.

Ok so a break for vacation but now back to the action. First parts and tools arrival. New impact screwdriver to get a stubborn stator bolt out. Done. New heat gun for bearings, no more open flames! New signals courtesy of birdsnest. Fuel tap and lines can wait since we need to build an engine. Cases look virgin…

Hey john, my experience with that green fuel line is that it lasts about 6 months before it gets pretty darn hard. After about a year it's close to rock hard. Definitely a recipe for future headaches. I'm also not a fan of those plastic quick connectors on scooters. I've worked on a few different scooters that someone installed them on, for me to remove them from the equation since they were leaking. In the dirtbike world many of those aftermarket quick fuel connectors are a failure point. As much as i would like to be able to utilize a quick connector on all my scooter, i still stick with the tried and true worm clamp method.

Yeah I’m not loving the green line either. I will probably grab some automotive stuff from O’Reilly, it’s not clear but it lasts longer. This was on a lark because I thought I’d be trying to start it soon. Ha. I’ve had decent luck with the quick disconnects so long as they don’t have a filter, those clog up. The fuel tap isn’t fast flow because Mercato was out of stock on those. May want to change that also.

I've had excellent results with the TOYOX hose that SIP sells https://www.sip-scootershop.com/en/product/fuel-hose-toyox_40281300 . I don't know if that's the correct inside diameter that is in the included link though. I've had the same TOYOX hose in my Lammy for the past 8 years with zero issues. I finally installed that same hose in a few of my Vespas as well. What's nice about it is that it doesn't kink.

Is it possible to need a fast flow tap with a 20.20 carb? I’m not even sure it could flow enough to warrant one.

Engine apart, crazy amounts of copper spray inside. Case fasteners missing many wave or flat washers. Crumbled hard plastic appears to be kickstart stop. I’m thinking all new bearings and seals. How do I determine if these reeds are ok?

Empty cases

If that's the steel LML reed, that thing will outlast us all. The rubber on the reed block is the weak spot on those things. I don't know if you can replace it, or you have to get a whole new block. Seems like it should be replaceable, though.

No gap between reed and block right? Should be fine but since you have it out.. could always upgrade the petal material.

Looks like it's got an upgraded mazz crank already? Btw, wth with all that copper inside cases? Curious to understand what the thinking is for spraying copper inside cases before closing?

Either way looks like you are having fun with it! It's always a rewarding discovery to pull one of these engines apart.

Yeah no gap between reed and block, seems like it is clean and go on the reed. On the crank - no makers marks, how do I ID it? You think it looks like a Mazz? I have no idea what a stock Stella crank looks like. On the copper, I agree, WTF?? 🤣

The copper was not me!

I swear!!

While I use copper spray, I only spray the gasket itself!

Look at the rod on the crank. If it’s got a little trident looking thing then it’s most likely mazz

Nah. I wouldn’t sweat it.

Lml vs mazz crank

No marks at all but looks mazz

Both Stellas that i used to have, the crankshafts has a groove milled entirely around the outside of the main crank web...like in this link here. https://www.sip-scootershop.com/en/product/crankshaft-lml_13315410?cr=e993ab67-6807-4109-bbed-f6374ebf9f9b&gclid=EAIaIQobChMI35HmioiU8gIVQQd9Ch2HmwDcEAQYASABEgIj7fD_BwE

Well whatever it is is getting a wash and going back in. Still undecided on repair the Malossi top end or move to my original plan of a DR or Pinasco. The Malossi piston is $120-150 depending on where you go. The DR kit is $200. The 150 top end I’m getting from Friday Matinee is free… choices, choices.

Honestly leaning towards the 150 - this engine will come apart again when it goes into the VBB (primary ratio for 8"). For now I’m building it to make the p go, while I rebuild that one.

Take at the VMC177. It's also cheap like a DR, but it's a modern top end.

That's looking pretty good - does anyone carry it stateside? Or do I have to do the SIP order thing via my usual suspects?

I don't know if the top of my head. Scooter-speed or mercato should be able to get you one of they don't already stock it.

If you're looking at a new plug-&-play cast iron 177 kit, I can recommend the Malossi. I do not have first hand experience with the VMC Super G (G is for ghisa I guess), but mista FreakMoPed reviewed it when it first came out. Compared to the Malossi, the cylinder casting was ragged and the port timings were lower. It did have a very slightly wider exhaust port. Maybe VMC made improvements. If you check it out, make sure the data is for the Super G and not one of its aluminum brothers--those have better specs.

yeah to be honest, since the return point on these scooters will both be low unless I paint them (not going to happen on the P), then the goal is good torque for hills and low budget, with minimal tuning time required.

I don't plan to hold the P, it's a put it back on the road and learn stuff project, but in the end the goal is to move it or I won't have room to roll the VBB.

I'm actually thinking the 150 top end will go on. That way I can decide later when I build the VBB how ambitious to get. If it totally sucks, I may chuck a DR at it but I don't have to decide that now. It does meet the goal of cheap and easy to tune....

The usual cast iron suspects (DR, Polini, Malossi, VMC) are all within about $50 of each other price-wise, so $ should not be the driver there. The more difficult decision is that for another $50 you can get an entry level aluminum kit like a BGM.

to be honest, I'm still scarred by my 40 page tuning experience with Malossi 210 where the damn thing would never jet in properly. My DR130 on the smallie was a lark by comparison. that's what's mostly holding me back from just cleaning up this malossi 166 and running it - which is still cheaper than any new kit. will it jet in easy enough on the 20.20? I'm assuming with a tame pipe and the reed valve it probably will. that's still on the table. But I think starting with the 150 is easy. swapping top ends later is easy.