Modern Vespa

I think this may be one of very few in the states. Its an 89 50 N, electric start, 3 speed. All original, still have italian reg papers, tool kit, etc. It doesn't want to kick over, so maybe its seized? Either way, i'm going to have so much fun with this thing. It's my first shifting vespa! Chassis code on it is a V5X5T.

Nice one.

I was able to get it running by thoroughly cleaning the gas tank, carburetor, and freeing up the piston from the old 2 stroke gas varnish. Took it for a ride after checking everything and was surprised at how bad it sounded. I inspected the exhaust and someone drilled holes into the muffler and cut off the tail pipe flush with the box. I ended up finding a proma exhaust for really cheap ($50). I installed it and upjetted the stock 16.12 from a 60 to a 65. It's still very slow but it sounds okay now!

https://youtube.com/shorts/GUHPNzEH_MI?si=BIXt5O1ZXCFISkVr

I'll have to think about kitting it. I'm not sure if the clutch will even hold the little extra power from the pipe.

Nice and rare !
What the N stands for ?

Thank you! The N is for 'nuovo'. I believe it has something to do with Italy removing the 1.5hp limit on 50cc scooters. I believe these made closer to 2.5hp. when I removed the exhaust I peered into the cylinder to see three transfer ports. It also had a higher flow exhaust elbow and a 16.12 instead of the typical 16.10 carburettor.

102cc kit ?

https://www.befr.ebay.be/itm/146384938372?chn=ps&norover=1&mkevt=1&mkrid=1557-169450-849249-2&mkcid=2&itemid=146384938372&targetid=325425753764&device=m&mktype=pla&googleloc=1001021&poi=&campaignid=20548327657&mkgroupid=153983449832&rlsatarget=pla-325425753764&abcId=&merchantid=661164763&gad_source=1&gad_campaignid=20548327657&gbraid=0AAAAAo9ZJxv7GfGuhnVuoVtwWw8tvFhQh&gclid=Cj0KCQjwgIXCBhDBARIsAELC9Zjdn5UTpqmUbiZL-QKAqyJl3nyZKEIB_NBeiTA9Oc0NEVh8RB4kOlIaArrnEALw_wcB

Not expensive and everything included !

Don't tempt me!

Thanks for that one Colin.

Cool scoot. Definitely wanna Hollywood Holt that bike.

Thanks. What's that mean?

See link for reference.......

?si=PSo0QWBWJaKAKQuj

I have Nuova too

There also was a "Roberta" version

That's so cool. I thought the pk50n was 89/90 only?

Well, the proma exhaust plus the upjetting has done the clutch in. 1st gear is fine, 2nd slips a little, and 3rd can't handle full throttle until the clutch grabs. Not sure if I want to even bother changing the clutch ( I have a newfren 4 plate on the shelf) or I just wait and start gathering parts for a cylinder kit (crank, cylinder, convert to 4 speed, different primary gears, etc) which will be pretty involved.
The 50cc + 3 speed isn't good for traffic in California, even local roads as it tops out at 35mph. Maybe if there was a small gear I can swap on and keep the basket in place? I also feel like the shb 16.12 is too small even for this. I can tell the cylinder has more in it...

Good point. I checked once again and really - my Nuova is 1989.
Also interesting that in 1990 was produced only 13 Nuovas
Can it count really rarity Vespa and have some really high price ?

I'd love to have that version! It doesn't hurt that the model has a ridiculously cool braid. Thanks for sharing.

Really not many of our scoots were made!

Well I got a racing idle. Flywheel side seal blew. Luckily I had a seal on my shelf that would fit and has 3 lip seal. I think it's for a steering gear box. I was also surprised to see my flywheel weighs 1790g. I was thinking it would be 2kg+. I have it back together but I'm going to go to my shop and bore out the 16.12 to a 16.16. Might as well have fun with the 50cc before I split the case.

Got the shb 16.12 reamed to a 16.16, set the timing to 18btdc. Up jetted to a 75 jet. I think it's too rich.

https://youtube.com/shorts/ACIQAQsCjwQ?si=Ae0bHjwDkNfJ45MP

I re jetted to a 68 mj and put the airbox back on and the performance is great. Plug a nice tan color. With the proma and bored out shb I would say performance has increased 30-50% it can do a solid 35-40mph on flats and going up hills is no problem.

That's got to be the best bang for buck tuning mod going.

Nice work, ditchdrift! Whereabouts in the Bay Area are you? San Jose Vespa Club, local to me, meets for tacos every month. If you're nearby, let me know - I'll send you details.

BTW, if you want to embed a YouTube short here, rather than posting the link, you can just edit the URL like so: Result:

It was a very good free mod. Took about 30 minutes of labor. Funny how they restricted this motor. With low timing and a small throat on the carb.

Thanks for the YouTube tip!
I'm up in the Benicia area. Unfortunately that's quite a drive!

After scooting around for a few days I told myself I'm going to have to take a look at the clutch. It slips badly in almost every gear. While I was doing that I told myself I'd pull the head and jug and maybe do some work to the ports to pick up a little more power. I remembered I didn't have a timing wheel that would fit so I also printed one. After I got the cover off I was greeted by a very dirty motor.

After pulling the head off I noticed that all the goo and dirt was emanating from between the head and jug. Looks like the head was not sealing well. This is also when I found out that I had a 50mm bore! It has a dr 85cc kit on it! Crazy that the carb has stock jets in it.
Decided to check port timings. Wow. They are horrible.
160 exhaust
111 transfers
24 blow down
.9mm squish
91 btdc - 38 atdc on the crank rotary valve.

I went ahead and spaced the jug up 1.5mm and took the port timings again.
171 exhaust
122 transfers
24.5 blow down
Ok that's a little better. I'll have to mill 1.5mm off the top of the jug. I went ahead and decided to port the exhaust port. Stock is rectangular, 17mm tall and 28mm wide. Very anemic. I decided on a more modern oval port with a flat top. 19.5mm tall and 32.5mm wide for 65%.
Exhaust port timing went to 176. Much more respectable with the conservative 122 transfers. Blow down now at 27 which is much better.

I also went ahead and pulled the clutch. It looked new but is burnt and the plates sort of warped. Luckily I found a newfren sport 4 disc local for $20ish. This pk has the 14/69 primaries. Yeah. Not good. I don't want to crack the case open yet as I'm still having fun with what came with the scooter so I ordered the $30 16 tooth gear. Should be good for maybe 10-12mph with my modded timings. I will also see if I can go to a 19-21mm carb. I have some phbn carbs that will work.
Next step is taking 1.5mm off the top of the jug and fabricate 1.5mm spacer. I do not think I will port the cases. It looks unnecessary with the dr 85 kit.

Hand fabbed the 1.5mm spacer, did a quick in frame port blend on the case. Plasticine keeps the chips out of the important parts. I know quick n' dirty is a hard concept for some people to get, but these cases will be pulled out for a full build after I have fun with what I have.

I also ported and blended the transfers on the dr jug. Looks better. Should perform a heck of a lot better with the port match/blend, the 176/122 timings, and the better blow down. Now I have to machine the jug down.

Any input so far? This is a practice in hotrodding and using what you have or can get for cheap. The real build will come later.

Nice work

Quick and Dirty? Using what you have?

What you are doing here is beyond Q&D. Not so many years ago this would have been considered high level tuning on a kit such as the DR

Well done sir. Be proud of your accomplishments and enjoy every (s)mile

Thank you! Most of my friends are against my methods as they just buy everything top notch and brand new. So they have really amazing bikes and cars. I got 4 little kiddos so I'm limited. Hah.

I finally machined the top of the cylinder down about 1.55m, I wanted to keep the squish pretty conservative at the stock .9mm. After assembling and checking squish it came out to be .92mm. Not bad. The rtv on the base spacer probably added some. I was able to put it all back together and fire it up. It's 11pm and I'm sure my neighbors hate me a little more now. I can tell the carb will need jetting work again. I have an order into sip for a polini manifold for a 21mm phbg that I have from one of my twist and go's and the 16t primary so I can have a little more top end. I may try to reject to see how it performs. It sounds about the same.

https://youtube.com/shorts/xlD8xeLBGds?si=6TkM5ttLp_tLELUV

Enjoying this.

You are squeezing out all the juice. Dig it.

Great job you did !!

Thank you. I'm sure with a real pipe on it, it would perform muuuuch better. If I can get a deal on an expansion chamber that I can use on the next cylinder will try that as well. Right now I have to figure out some safe jetting and take it for a ride. I didn't think this would affect the jet sizes that much but it definitely can't hold an idle right now.

Now I understand why you have plasticine

Hehe, and in all different reject colours!