Modern Vespa

100 Sport. Need torque on a tight as possible budget
Not going to go on the freeway with this bike -- just need to get home without embarrassment.

So far on the list:
Polini 130
CIF four gear kit
SIP banana
Piaggio 3 plate pk clutch
24/61 primaries
All other rebuild bits (bearings, seals, cables...)

Any advice or WTH are you doing welcome. Going in pretty much blind here on a SF.

You might want to take the engine apart before ordering anything.

I can see a few areas which might need attention:

- wonky crankshaft
- worn/loose primary basket
- shims for the primary (because the 4 speed is a PK if I'm not mistaken, better to play safe than to need to wait for those if there's spacing issues)

Bike looks great!

For the PK clutch, are you getting PKXL2 style w/ cover that has rack & pinion plunger? They are really nice, much easier to release - they are like a Cosa clutch compared to a P clutch. What do you have in mind for a carb, I like a 20L if you can find a manifold, or step up to a bigger PHBL.

Thanks 108!
Funny how I made a stand for a bike I swore I'd never get

Tried to split the cases without knowing the clutch has to be removed.
1st lesson.

Yes!
3 plate okay?
Carb is stock 19/19. Someone added a Polini manifold in its history.

Funny how the world works… that's good karma coming back at you right there…

Oh forgot! I found the clutch puller tool and primary holder tools to be super important.

I think you can get away with ramming a screwdriver/copper coin in there for low torque builds.

Not sure how to remove the clutch without a puller though. Might be loose in the first place, which is good, you can remove it, but bad because it shouldn't be loose.

ray, is that polini reed on there? or just a polini rotary?

if it's possible at all within budget I'd get a polini CP20 or 21 carb.

keep the 100 sport primary gearing, it'll be fine in the city with the 4spd gears. or if you're looking for something deeper, I might have some gently used stuff.

what else is cooking in the block?

You'll be glad you went with the PK XL2 clutch cover. It's worth every penny.

Will those cases take an egig 170? That'd be my choice for cheap top end if they'll fit.

There is interesting cylinder under the SIP brand. It seems the same as VMC GS 125cc but with reworked base(so you don't need to cut off ignition dust cap from the case) and smaller exhaust port.
It cheaper than Polini but more powerful(?).
I'm very interesting in that cylinder to put it on my PK 50 S for humble built because I have VMC GS 125cc on my 50 Special and it performs very sweet. It must paired with XL2 clutch then.

Don't forget to add new cylinder hardware!

You need the longer studs for the barrel. Also, I don't know if a 100 spot cowl fits, you may need a 125 piece

Why is this VMC 135 not a better option? Bigger and cheaper. What am I not seeing?
https://www.sip-scootershop.com/en/product/racing-cylinder-vmc-gs-132-cc-6-travasi_14002600

I'm absolutely agree.
But in my case I had a very nice discount on 125, it turned near $110.
And for mount VMC cylinders you need to cut ignition dust cap and then mill cylinder mount surface.


With SIP VMC cylinder you need only to match ports. Thats why I'm thinking about it for my PK. I want stay with original ignition and SHBC 20 carb without lot of modifications or expensive parts.

Nice deal on the 125.

Well that's no go for cheap. Milling the casings is not for most guys in sheds.
The SIP description did say this
But wouldn't be the first time these descriptions were too general to mean anything.

100%

The CP58 looks pretty sexy… I've started to see people receive the kits…

But the egig isn't budget… the crank, clutch and primary are a killer…

I forgot about the crank, but wouldn't count the clutch unless the goal is only build something that wouldn't cause a stock clutch to slip anyway.

Same thing for the primary, assuming that the power won't be so far out of line with the gearing that you wind up with an unacceptably large hole between 3rd and fourth.

Do I need another clutch cover too?
So far, only the PK XL2 clutch and pressure plate.

This list has gone from Egig 170/new cases to DR/3 speed and back

Clutch puller arrives today. Hoping I can use this crank.

I'm on the modest side of the equation. My DR130 was a good little runabout, with a DRT short 4th and polini CP21, with Polini exhaust. I'm sure you could do better with the Polini cylinder, as most people dog the DR. No need to get nuts, but don't skimp on the DRT short 4th tree, the stock 4th is too far away from 3rd.

If your current clutch basket is in good shape it will enough to throw in new Polini spring and fresh three or four plates kit: NEWFREN 3, NEWFREN 4, Surflex, Malossi 3, Malossi 4. IMHO it will be absolutely enough for DR, Polini, VMC GS in your setup. Just remember that Malossi springs is the hardest of all except the Polini Wave spring. I have it on my Special now and can say that it is too much even for me, my setup absolutely not need so hard spring.

Hey Ray, you'll definitely need a cylinder shroud cover from a PV. The cover for the 100 sport is too small to fit the Polini 130.

If the crank's in good shape, use it. 100 sport crank has aggressive timing, similar to ET3's I believe.

I'd go for a bigger carb - either a Dellorto 24 or Polini CP24 - both of which require a larger diameter inlet pipe.

For maximum joy from the Polini 130 consider an expansion pipe and some tried and true O-tuning. It comes alive with the barrel lifted 1.5mm and the top shaved to 1mm squish.

On the A very "Special" project build I went for the newer Polini 130 (new head + GS chrome rings), Polini 51mm crank, Polini CP24, stock 50s clutch with Stoffi 12 spring conversion, 4 BGM plates with reinforced retaining clip, stock PK125 box, 25/69 primary (more room to play) and an Egig Python S...

Studs are included with the kit. Cowl added!

100 sport had a good clutch cover with the longer arm compared to the earlier prima style. so worth checking out what you have before ordering.

I would think that along with the stoffi setup and some good plates should be more than adequate for a mellow polini setup and not induce the lego man death grip left hand.

What I have is part number 990855 1A. The cover in the pic is a 990855 5A.
I'd love to convert it to the rack and pinion plunger that V oodoo mentioned, but when I look it up it comes up as "does not fit your model."

Arm is welded like the pic vs held with the pin, fwiw.

if you try to run an xl2 clutch with that you may find you cannot achieve the throw required. i tried that and could never get the clutch adjusted. I gave up and ran the single polini spring with 3 plates successfully with my DR130.

compatibility of the cover and the clutch is a big deal. you'll need an xl2 clutch cover to use the xl2, from my understanding. and then what they'll do is not sell you the whole thing, but a bare cover. when you go to buy the bits you'll see that most of them are available, but not quite all, so go figure that out.

maybe others have had better luck with the xl2 clutch cover setups and can give better instructions, but that was my experience.

I run that cover/plunger with an XL2 clutch on my bike with no issues. looking at lever arms it seems to me it would have more throw than the rack/pinion style.

I also ran that cover the standard 4 plate clutch without issue.

there are several lever lengths on the old style cover, i think. but on whatever I had, when I got the cable adjusted to be near contacting, there wasn't enough throw left to get it to engage.

I'm with you.
I tried XL2 clutch with V50 clutch cover on my Special - no luck.
I tried XL2 clutch with SIP XL2 clutch cover on my Special - no luck.
I tried same XL2 clutch on XL2 cases with original XL2 clutch cover - and it work as to should.

Ray8 just don't forget that XL2 clutch basket often rubs on the primary basket when XL2 clutch mounted on non-XL2 gear tree and non-XL2 primary is used. Also gear tree and kickstart shaft needs to be shimmed.

Reed. Mazz crank. Stock cylinder (transfers enlarged a bit) and pipe
22/63 primaries. Clutch looks barely used. Kickstart buffers look new

Not sure what to do with the rest of this bike. I could powder coat it with little work, maybe a Canadian spec no bug eyes.
Or just Owatrol and leave the holes

Loving this!

I REALLY loved my all stock PK125XL engine. I ended up swapping in a DRT short 4th and the scooter would hold just over 55mph on a flat. It was very manageable and forgiving for cruising around town. I'd eventually like to find another PK125 and keep the engine all stock.

Knew I forgot to answer a post… lol

The amount of torque the egig produces, especially if you combine it with the unisex exhaust, a stock clutch would definitely slip. Needs a 4-5 plate clutch plus stronger springs to survive.

Primary to go hand in hand with clutch, I can imagine the primary to flower out and have those plate wear teeth marks there.

The 4 engines I've taken apart so far all had that issue. Plus the basket and the cog being loose… these were stock engines too which seemed weird, but granted it's just held down with a bunch of small rivets.

jazz full circle or standard? did they open up or flow the intake at all, or just kinda snap it together?

22/63 is purrrfect. sort the clutch and you'll be styling.

make it Canadian spec, or if you want the blinky things put 'em in the handlebar ends. I'd leave the holes and just hit the thing with some shine juice and roll.

Here's the crank and inlet.
51mm stroke. 20/19 taper. It's in new condition.

Ball bearing on the flywheel side vs what I was expecting. Made for quite a time case splitting. Went woodpecker on that thing without heat.

Current list is the Stoffi clutch spring and Newfren four plate (currently has four. Everything is in great shape), so I'll be saving enough for something else(?)
Otherwise, list more or less as above... +35 items!

This conrod looks massive! I never saw it.
Can anybody shed some light on to how(good/bad) non-reed crankshaft works with reed intake?

man that looks totally serviceable, I'd 100% run it. while the "small taper" isn't the ideal, I think it's more than sufficient for moderate power applications. also, if you're not looking to break the bank, you can convert over to electronic super easy with the stock flywheel and a little stator rewire.

inlet and porting seems to be well done. I wouldn't touch a thing.

ball bearing is always a hassle, especially if they've been locked in there awhile. arguments both ways for the different bearings, but I always go two piece on rebuild.

should be a good little ripper, all those parts together make a nice set up.

works fine. I'm running something similar, albeit more toward the bell shape and a lot bigger case inducted reed. my low end is a little meh, but that's because of the huge carb and the cylinder/pipe setup but with the light flywheel it'll pull fine down at the low revs.

Awesome.
Thanks so much to all of you.

Going to replace most all the bearings so I don't have to think about it, even though they look new. If the stuck Xmas tree comes off with the bearing I'll keep the other FAG needle bearing that looks new, and avoid getting a blind bearing puller.
Clutch side crank bearing is a currently a sealed bearing

I think you can get away with the fag needle bearing. Of all the engines I've taken apart, none seemed to have an issue which was different to installing a new bearing.

Went through a saga with finding the right blind bearing puller for that. And I don't recommend a slide puller… lol

I ended up buying one with 2 legs.

The clutch side bearing all had to be replaced.

A sealed bearing?? Would still work, but would wear out super fast.

Wonder why they didn't just remove the seals?

Was only able to free the Xmas tree with heat… a lot of heat from the flywheel seal side and it'll drop out.

sounds like a solid plan man.

I *might* have that blind puller if need be. I find that usually if it sticks in the case heat will release it.

lolz on the crank bearing. that's a little wacky.

anyway if you get stuck just hit me up if I don't have the tool, I have a way to do it without. and if you need some dumb little clip or whatever that went missing or forgot in an order I probably have one chilling out here.