Modern Vespa

I've been spending a day researching smallframe 100's and am trying to figure out all the differences between a 100 and a 100 sport. I figure I should throw this question out to more of the knowledgeable guys on here besides just randomly texting greasy!

It could help myself and probably someone else looking for this stuff later on.

I can't find either in my Vespa Tecnica books, nor another book I have called "Vespa: All the Models" and the only two sites I can find minimal info on have incomplete details.

Scooterhelp only gets into the engine/ignition differences, with a couple photos of the different headlight, petcock and turn signals on the 100 sport:

100 - http://www.scooterhelp.com/scooters/V91BT.html

100 Sport - http://scooterhelp.com/scooters/V9B1T.100.sport.html

Smallframes.com only has photos of the 100, but a lot of them:
http://www.smallframes.com/100guide.htm


The list of differences I can tell from all these sources including image searches on google are:

100

• 6v Igntion
• Vespa 50s style small round speedo
• 60's style headset switches
• no battery or door left side
• euro p style tail light
• turn signals on the handlebar ends
  

100 Sport

• 12v Ignition
• gumdrop style speedo
• P series headset switches
• battery with battery door, left side
• rally style bakelite turn signals and stems attached to the headset and cowls
• tuna can tail light
• US petcock
  

This is everything I can tell from those links and photos available online.

I'm curious if there are other differences in the wheels/hubs or the engine casings, cylinders, pistons, crankshafts, etc?

Both models share the same engine and frame numbers despite these minor differences: V9B1M and V9B1T

As far as wheels go, I noticed the 100 has the 4 lug 10" rim. 100 sport would have the more modern skinner rig with the 5 point hub. Tire size the same.

I noticed the P style key switch built into the headset, sealed beam bulb with the chrome bezel and hand grips being different for the 100S. The seat also slopes different. The 100 sport has the same seat as the V90s where it looks like the 100 has the same seat as the ET3's. Fan cover looks black on the 100 vs grey on the 100 sport. Horn is the larger 3.5" DC style on the 100 sport vs. smaller AC horn on the 100.

As far as the 100S engine goes, the crank would be different on the flyside to run the different stator and 12V flywheel. Other than that, I can think of any other reason that the cases would be different. Both share the same carb and manifold.

Good stuff! I've got what i think is a 100 waiting for me back down in Florida. Trying to get a sense of everything before i get a hold of it in person to know what I'm dealing with.

So the engines are essentially the same minus ignition styles and any necessary changes to accommodate those differences. They are equally tunable?

Either one more desirable?

Quick quick way to tell the difference is that the 100 Sport has P-series headset switches, USA DOT Tractor taillight, and bug-eye turnsignals

Small frames are fun but i've never tried to tune a 90/100 sport. Always a 125 motor with the traditional cylinder studs that go all the way through the cylinder and head. I dont even know if theres aftermarket kits for the short stud cases??

I'm assuming some of these will fit:
https://www.sip-scootershop.com/en/category/klassik-vespa_2/tuning_1177/vespa-50-125-pv-et3-pk-xl_T4/cylinder_1931/racing-cylinder-80-125cc-stroke-51mm_2324?model=eyJzY29vdGVyVHlwZSI6IntcIm5hbWVcIjpcIlZlc3BhICA1MC0xMjUvUFYvRVQzL1BLL1hMXCIsXCJzbHVnXCI6XCJUNFwifSIsInByb2R1Y2VyIjoie1wiZ3VpZFwiOlwiYjk2MjM1NDUtZGIyNC00YTYzLTljY2EtMTE1MTg3YWFmZmRkXCIsXCJpZFwiOjYsXCJwcm9kdWNlcm5hbWVcIjpcIlZFU1BBXCJ9IiwibW9kZWwiOiJ7XCJuYW1lXCI6XCIxMDAgKFVLKSAvIDEwMCBTcG9ydCAoVVMpIDEwMCBjY20gMlQgQUMgJzc4LSc5MCBWOUIxVFwiLFwibW9kZWxfbnVtYmVyXCI6MTE1OH0ifQ%3D%3D

Kinda a random project that I don't expect to depend upon for regular usage, so I'm willing to experiment on this one a bit.

I'm not sure if the original short stud pattern matches up with those newer kits. Another thing I also just thought of is that there could be fit problems with a newer cylinder skirt and the cases that receives them. New skirt might be too deep for the cases since the OG cylinders sit on top of the cases, not inside them.

Take a look at the pics below and you can see how the stock cylinders is short on the bottoms and have a cut out in the fins to allow you to reach in and tighten nuts down onto those studs.

on the 100 motor the spigot opening on the case is the same size as primavera/125 cases. Stud spacing, size and pitch is the same. Simply replace the short studs with full length ones. Crank is the same as Primavera too. Any smallie Cylinder kit made for 90/125 will fit, standard or aftermarket. I have a Polini 130 kit on my 100 sport.

Main differences of the 100 Sport engine:
100 sport is 3 speed
100 cc cylinder size
short cyl studs
bolt on head
exhaust port location is different than 90/125cc
** 90/125 exhausts will not all fit properly on the 100 sport
Neutral switch threaded boss on case
Ducati Flywheel & stator: points ignition
** can be switched to 12v Electronic Ignition same as P200E. Swap stator, or rewire existing; while using the same Ducati flywheel. highly suggest simple stator swap!

Note that the 100 sport Flywheel is heavy. Very heavy compared to other SF flywheels; as far as I can tell. Not really an issue unless tuning. Definitley somewhere that some power can be found for sure. I'm waiting for mine to snap off one day when I redline it through the intersection

Little more research given all the discussion around studs and skirts, etc. I don't think the stock 100cc cylinder or pistons are available anymore as I can't find them on any store.

So it sounds like if you have an engine that has some damage your options are to either find someone selling decent used originals or to install a tuning kit.

Try Kyle's Scooter Shop. He had a set of NOS rings for a 100 sport we were working on. He has quite a few hard to find parts.

www.kylesscootershop.com

I don't actually need anything right now, just trying to understand all the little details of them. But I'll know more of what if anything i need I'm a month when i go pick this one up. And Kyle will be my first stop if the top end parts need replacing. From discussion with the seller, it's only gonna need new gas tank, petcock and carb clean. But you know how it goes, once you get a closer look, there's always something else that can be worked on! I even spent some time looking at 4 speed conversions and a replica 90ss glove box with functional gas tank instead of just being for show and storage, which then led me into trying to find out if anyone has routed the replica reserve tank into the main tank to act as one. Maybe it's wrong, but I'm not against replicating a 90ss using the 100 as foundation for a whole hell of a lot less!

It's crazy how many tangents one can end up in simply by delving into a new model vespa. All so similar, yet so different.

I've seen a few of those 90SS Vespa's and thought they were some kind of resto mod until today. I want one, wonder what motor I can stick on one.

If original, they ain't cheap. I'm guessing there are probably a few more in USA that are faked like how I want to do. Using a 50s or a 100 frame and just swapping and adding 90ss replica parts.

https://scooterlab.uk/part-1-vespa-90ss-replica-build-feature/

https://scooterlab.uk/part-2-vespa-90ss-replica-build-feature/

i agree, when i got my pts 100cc, i was clueless to find what kind a engine does this smallie have, frame look like a 50n 1966 from front view but the back side look like a primavera while the engine is a 100cc with a 19-19 carb on a 3 speed transmition plus a very low compresion, took me a year just to find the correct number for the jetting not to mention all those subtitute bearings even folks here dont know exactly what kind a engine i have but still despite all that i still like riding it and smile, especially in a heavy trafic jam where everyone stop but i still keep on going while dodgeing all those cars mirror, its a golden moment for me (the only moment when folks literaly said my smallie is fast)

Good luck with the 100cc and cheer

Wow I didn't realize the wheelbase was shorter on 90ss than on other small frames. Also just noticed the leg shield is narrower up top on the 90ss than on the 100. So yeah if I wanted to make an accurate repro 90ss I would have to figure out what length wheelbase the 90ss is and the 100 that I've got, and do similar to this guy, shorten it if needed. Also would need to chop the leg shield to shape. But easier solution is just leave it as is and throw the repro reserve tank on with wheel underneath! thanks! I can imagine how a much tinier smallframe can really help out in that situation. I'll be using this around town at my parents down in florida. No highway or longer trips. .just when i wanna run to the store or meet them at the bowling alley down by the beach!

Little more research on wheelbases..

Target:
90 (V9A1T) /90SS (V9SS1T)
Wheelbase: 1160mm
Length: 1650mm
Saddle Height: 745mm

Donors:
66-70 50L (V5A1T) / 65-68 50S (V5SA1T)
Wheelbase: 1166mm (6mm longer)
Length: 1630mm (with sidebar that a 50 elongated exists at 1655mm)
Saddle Height: 745mm

69-83 50R (V5A1T) / 69-83 50 Special (V5A2T, V5B1T, V5B3T)
Wheelbase: 1175mm (15mm longer)
Length: 1655mm (5mm total frame length longer)
Saddle Height: 745mm

67-83 Primavera/ET3 (VMA2T, VMB1T)
Wheelbase: 1180mm (20mm longer)
Length: 1665mm (15mm total frame length longer)
Saddle Height: 750mm (5mm higher)

100 (V9B1T)
Wheelbase: 1180mm (20mm longer matching the Primavera frame)
Length: 1665mm (15mm longer, matching the Primavera frame)

From photos it appears the 100 frame is more similar to a 50s but the measurements on smallframes.com says its dimensions match the primavera.

It would be very intersting when I finally get my hands on this to see what it actually matches up to. And given this info, if you really wanted to make an accurate replica of a 90ss, then you would have to shorten the wheelbase 20mm like what the guy in that scooterlab article did by chopping the tunnel and shortening. Only problem is the 100 total frame length is 15mm longer than the 90.. so shortening the wheelbase by 20mm leads to a total frame 5mm shorter than the 90ss! So not exactly accurate even with that attempt to mod the frame. I'm assuming the shortened wheelbase leads to the reserve tank and tunnel mounted spare tire to fit more accurately and have the correct lines with no gaps, otherwise they will have about a 20mm total gap between the seat and the leg shield to tank/tire. But given all those donor options.. it appears the best one to start from at least to get closest accurate wheelbase/length is either a primavera or a 100, if you go the route of chopping and shortening. And if you don't go the chopping/shortening route, then it appears the V5A1T/V5AS1T "elongated" frame is the closest match. Not sure how to tell other than physically measuring which V5A1T is the elongated frame version.

Plus either replace the leg shield with repro, or cut and shape it to match the 90ss.

If my memory serves me well. Back in 1983 when i had a v100, my friend got a brand new 100 sport. It was a rather nice green colour. The alternative was a rather horrid beige They were both equal in performance; many people didnt buy them in the UK due to the stem indicators and many took the indicators off. So i guess the Sport in the Uk was a transitional filler awaiting the PK range which arrive shortly after.


The one thing that struck me with the Sport is that you couldnt turn off the headlight as you could with the v100. My mate told me the sport was designed for the USA market where driving with a headlight turn on within the USA was compulsory, hence no off switch.

Yes in the US motorcycle headlights are always on by law.

So was it the case that imported v100's from Italy to the USA had this modification too, no headlight off switch?

I have not seen one in person yet, but I would believe so. That's the reason for this thread. There isn't a whole lot about either of these models documented in any of the books I have or online. Trying to get a sense of them from other people's direct experience. In fact, the stuff online I've found do not mention v100's being imported to the US, just the 100 sports. So I don't know if they were sold here, or if they only showed up from individual owner imports.

P200/P150 did not have ability to turn headlight off. Just high or low beam.

I'm curious to see this v100 when I finally pick it up.

Scooterlounge has this to say about smallframes sold in the US: No mention of the v100's just the 100 sport.