I just had to do this one. A friend took over a local scooter shop and to say "Good Luck" I decided to give his (broken down) Stella the "thatscooterthing"-treatment
We are talking about a 27.000 mile old mint and rust coloured cut down Genuine Stella 150. 5 port engine with reeds
I got the engine without cylinder, he had a seal failure before it got pushed into the back of the shop and time did not allow further work
I gave it a good clean and ripped it apart. It already had a Mazzuchelli cut crankshaft (although, we are running reeds, the only "cut" helpful here is reduced crank case pressure for less peaky power development) and it had a lightened flywheel (the starter ring is machined off and it is balanced)
I went ahead and rebuild his clutch with 23 teeth and 65 on the primary, giving it an overall longer transmission, identical to the P/PX200 vespa models.
Around the same time I started playing with live streams.
Here is the link to said stream.
I also epoxied the cases and started cutting the ports. I have done Polinis to LML engines before and the matching process is quite... extensive
The cylinder originally has rather low timings but a high squish, with 1.1mm. I wanted higher timings and a lower compression for less heat. So i raised the cylinder with 2 gaskests and a spacer by 1.94mm and decked the top by 1.75mm (acutally a local shop decked it for me for $45). After that I got to 121/122 degree intake. All that was left was to raise the exhaust and make it nice and wide, to 68% width and 182 exhaust duration. We are going to run a JL/Prima exhaust that was happily gifted by a mutual friend from Chicago from Moto Fabrica
Now it was time for the intake:
Boyesen reeds, "as usual" and a PHBH 28 on a Polini intake, with uni filter. tried and tested setup, so i thought it would be the best way to go. Sounds rad too. I also mounted everything together
It was then time to deliver the engine and mount it up at his shop, Metro Scooter in Cincinnati. First look at the bike it self and a first start video.
And then it was all together, needed some smaller hiccups fixed and I finally got it out for a test ride this weekend.
It needs some jetting, which I will do tomorrow before it gets delivered, but boy oh boy is it fun. the longer gearbox is great and it has all top end power. It just... goes. and goes. and goes. Although it is still in break in it wants to go (audibly) far beyond 8000.
Loved working on this, and I am glad I can help someone out who deserves it as he busts his ass to bring scooters to our city!
Full Build video coming soon