Modern Vespa

Has anyone done this? Seems like a better (but more expensive) solution than installing a sight glass. With the sight glass you still have the problem with adding oil to the new-style filler/dipstick hole. I don't like the idea of needing to bring a big filler funnel with me on long trips--which seems necessary with the newer-style setup.

I think you would have to change the variator cover too, because it's indented for the dipstick. The HPE does use the same oilpan gasket as the old engine.
The problem with the sight glass oil pan, is that installing it voids your warranty. The best solution is likely running something like 15-50 oil. This should alleviate a bit of the oil loss in the engine.

Motovista, I wonder if thinner, not thicker oil is needed. In my opinion most of the oil loss occurs when oil is cold and hydraulic pressure is highest. The colder oil viscosity overpowers thin, low tension piston rings and oil is burned up. With an oil pressure gauge installed, you can see that oil pressure doesn't settle to 'normal operating range' for about 5-7 minutes until engine warms up. A 0-40 oil would eliminate some of this cold oil viscosity and still act as a 40 weight when hot (as per Piaggio spec).

It's not just the oil loss, but the difficulty of checking, changing, and filling oil with the new dipstick location and design. I live in Alaska so warranty loss isn't an issue since no warranty service is available here.

For adding engine oil to my GTS on road trips if needed, rather than carrying a funnel, I used one of those clear, old-timey cafe, squeezable, ketchup/mustard style plastic bottles that I bought at a dollar store, filled it with motor oil, then had a length of appropriately-sized plastic fuel tubing that would fit onto the bottle's nozzle.

I still had to crawl around on the ground to add oil, but the flexible tubing made the job easier and less awkward.

By the way, I also have the sight glass cover.

https://modernvespa.com/forum/post2639052#2639052