Modern Vespa

I may have found a donor engine for some parts that I need but I'm not entirely sure if the parts I can get from it can be placed in my v9a:

basically, I might get a primavera engine, with the hopes of using teh cylinder/head/piston, and the gearbox, etc... anyone foresee fitment issues in the v9a with those parts from a prima?

At the very least I think the cylinder/head/piston will fit. Stroke's the same, and the other thing that leads me to think it fits is that no one makes the differentiation with the malossi/polini kits between 90/100/125... so I figure it fits.

But you guys know more than I.. thoughts?

What year is the 90??

this is ripped from scooterhelp.com:

Casings: The crankcase mouth on this model was enlarged in 1966 to 61mm - an identical size as larger small frame motors like the 100 and Primavera. From 1963 to 1965 the crankcase mouth is only 56mm and the piston is different. See "kits" below for limitations because of this. The 16mm intake manifold is attached with only two studs compared to 3 studs on later PK models


Bearings: Early motors had one piece bearings on both sides of the crank which are a pain when splitting the casings. The one piece flywheel side bearing can be replaced with a two piece to make splitting the casings easier in the future. Use an SKF N204ECP for the conversion


Crank: The crank is the same as the 100 and Primavera models up to the Primavera ET3. Any smallframe crank can be installed in this engine. Popular changes are to install a PKXL or PK125ETS crank which allows use of many different flywheels. Flywheel side bearings and seals will differ for these conversions.


Piston: On pre 1966 engines the pistons have a different wrist pin set up using a 14mm pin and only a bronze bushing aat the small end. Post 1966 engines have a 15mm wrist pin and a caged roller bearing small end (see pic) .


Standard barrel: The original 90 barrel has only two opposing ports in the barrel. The later 100 Sport or Primavera ET3 barrel & piston has three ports and can be used on earlier models as the third port is completely contained within the barrel casting (i.e. no casing modifications are necessary. Both the barrel and the piston will have to be replaced for this conversion.


Kits: Larger bore kits from Malossi and Polini (and others) can only fit on post 1966 engines without enlarging the mouth to allow the barrel spigot to fit.


Ignition: The original 6V points can be replaced with a 12V electronic set up off a later Primavera ET3 or any of the PK range systems. The flywheel and stator off an ET3 bolt right on, but many PK flywheels use a different taper. Check here for a guide to smallframe cranks.


Gearbox: Any smallframe gearbox will fit in the casings but almost all the parts will have to be replaced.

It's a '73

Hummn. Sounds like everything will fit.

Didn't see that on scooterhelp before. I occasionally find that site tricky to navigate.

Hummn, what about the stators?

Looks like it looks it should work on scooterhelp, but I'm particularly weak on electronics.

I need to figure out if it's a battery-less Prima or what...

As long as it's post-66 and pre-78 it all should swap over just fine. 74 electrics will be odd if it's US-Market.

It is.

Yeaup.

I wonder if I'm going to need a new exhaust, while I"m at it. I presume so.

I've got a few prima cylinders and heads you can have. also have a new piston but not sure if it's standard or oversize or if it will fit the cylinder.

Cool, thanks dude. I'm not sure if this is actually gonna happen yet - but if it does, I might hit ya up.

The electrics are weird on a '74 US primavera .... battery bike ... but you can ground out the yellow lead, tie the greens together, and run it into a 6 volt regulator and then out to your bike electrics.

It's not perfect, but it works.

Consider one of those scooterworks EIK conversion harnesses for your smallframe if you're going this route. It can work, and i can help you if you have questions.

-Eric

still need to figure out what year the prima is

don't worry about what year the prima is. all years of the prima will have the parts you want and I'll take most of what's left over.

the other half of this particular equation, and what precipitated oscar's research here, is the fact that the flywheel side case on the et3 i just bought is cracked. oscar and i located the primavera engine for sale. i get the cases, he gets the rest for his planned conversion.

what, if any, issues should i be aware of when replacing my et3 cases with standard primavera cases?

btw, does anyone have a line on primavera cases ONLY for sale? oscar seems down with splitting the cost of the engine, as he was planning a conversion, anyway...but i'd like to know if i can find just cases for sale before we pick up a whole engine next weekend.

I bet in a different thread this might get more responses

I hope it gets some because this is an (easier) path out of my "get this stupid bike running" dilemma.

As you opined, I have a garage full of bikes that don't run, and this upsets me. It shouldnt' be the MP3 that's goin' strong...

no issues with swapping over those cases.

Hard to find decent cases for sale anymore - SIP has a bunch of the Indian PL170 cases (Indian version of smallframe), and I think ASC was getting a couple things from them as well. They are large taper like PK, instead of small taper like Primavera/ET3/etc. , so different bearings and crank and flywheel are needed.

excellent, thanks. (i don't wanna be caught empty handed if i ran into some damn something or other that i didn't have on-hand to be able to make the swap. i want this done asap with as few $ spent as possible.)

Are they the 24/25 large taper cranks like the ETS or the 20/20 large taper cranks like the PKXL? If they're the 20/20 version, no conversion seals and bearings would be needed. I don't know of any conversion bearings or seals to put a primavera crank in ETS style cases.

Also, do those cases take the Sensation style one-cable push/pull shifter?

Not sure about ASC, but the SIP ones were dual cable 24/25 last time I checked.

Nice! Those sensation ones were so appealing until you came across the shifting issue.

Decent cases, just way too expensive after import tax and currency conversion.

I'm gettin an et3 together for a 1000 mile race next year - I need to get a laundry list of parts over to you and see if you've got them in stock/can source.

Why not just use the Primavera engine switch it to ETI and make your own wire harness and be excited!!!

Oh yeah I need a V90 piston the one I have didn't work too well when I made the cast due to it having a chip that's where the metal leaked out
It took about 350 pop cans to make a piston

How's yer diabetes treatin' ya?

I have Primavera/ET3 only cases for sale. http://www.scootersoriginali.com/osc/product_info.php?cPath=1_177_220&products_id=1765

Piaggio made primi/ET3 cases.

We've been doing a roaring trade on them into Europe.

Andrea

I don't drink soda that shit will kill you , but at work we have a recycle bin and it took forever to get that many cans everything is plastic now

If anyone has some old beat up pistons send them to me I can melt them down it takes about 3 pistons to melt to make one piston