Vespa and Stella - a whole bunch of questions...

The original 2-stroke Genuine scooter and its 4-stroke manual and automatic offspring

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Vespa and Stella - a whole bunch of questions...

Post by Chatis »

So, trying to get my scooter’s running well before winter. Here is the scoo(p) .

I have a 1963 VBB that the seal failed on the main drive shaft. Rather than rebuild I purchased an LML engine from Scooterworks. With some futzing with the rear shock I got it to fit but getting the carb box cover on and off is a test of will. The exhaust that comes with the engine does not fit on the scooter so I installed the original exhaust. Seemed a little small but it fit. The carb settings and stack is as it came. I don’t know what it is – I will pull it soon to see. The scoot is a rocket. Pulls hard through all gears and really performs. I don’t have the balls to tell you what the top end is.

I also have a 2003 Stella 2T that I have rebuilt the carb and performed the “Bald John” upgrade to the stack. It has a P200 filter and a P125 unrestricted exhaust. Thing is, the Stella does not come close the performance of the Vespa. Any ideas??

One of the reasons I rebuilt the carb, other than it had been sitting for years before I got it, was that the carb box was full of two stroke oil, and it was running down the back of the engine. When I rebuilt the carb I cut new thicker gaskets and made sure all bolts were torqued properly.

The two stroke oil is still building up in the carb box. It’s not coming from the front of the carb - tube, pipes, pump, etc. – I have checked that. From my readings it can only come from the gasket – splitting or leaking somehow – or from blowback into the carb box where the fuel evaporates leaving only two stroke oil. The first of these two seems more plausible. The second would have the flow going counter and through the filter element. Other than being messy and creating stains on the floor should I be concerned that there is not enough two stroked getting into the cylinder? Should I be putting some two stroke into the fuel tank? This seems to be a common problem.

So in summary:

1. Why doesn’t my Stella go like my Vespa?
2. Where can the two stoke oil be coming from?
3. Should I add two stroke to the tank?

Excitedly awaiting wisdom.

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Post by ericalm »

This is kind of interesting. I know of folks who have swapped various engines into VBBs and the performance was still pretty low key. I do not know if they altered the gearing, though.

But… Still on 8" wheels on the Vespa? That may be one factor.

And it's possible the Stella is bogging down if you're getting that much oil in the carb box. Is the air cleaner flooded? That might slow it down.

May be some help in here:
Eric // LA Scooter Meetup Group // Stella 4T // Vespa LX // Honda Helix // some, uh, projects…
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Post by BuddyRaton »

Yeah I was wondering if a 10 inch conversion was done too. Someone asked you about this in another thread but no answer.:wtf:

We really need more information. What are the numbers off the old motor? What carb and jetting is on the new motor?

Generally an LML crate motor is premix and doesn't come with an exhaust. What exhaust are you running? What do you mean by a P125 unrestricted exhaust?

What timing are you running?

Can we have some photos please?
"Things fall apart - it's scientific" - David Byrne

'06 Cream Buddy 125, 11 Blur 220, 13 BMW C 650 GT, 68 Vespa SS180, 64 Vespa GS MK II, 65 Lambretta TV 175, 67 Vespa GT, 64 Vespa 150 VBB 64 Vespa GL
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