Modern Vespa

I have a Mikuni VM28 in my pile. Flatslide and actually part of the TM family, don't know why the designation is weird on the 28mm.

Would it be an upgrade over the 24/24 I'm currently running on my Stella? 177 Polini kit and Polini pipe.

Would it be worth going through the effort of changing intakes and such?

Also in my pile I have a Dio pyramid reed block setup that although made for a 50cc engine looks like it would flow a lot more air than the stock Stella flat reed. It's designed to be used with a 28mm carb. Looks like I could basically just cut a thick aluminum plate to create an adaptor to fit the Dio intake on there. Drill, drill, file, file, Bob's yer uncle brother wife.

It's worth trying. I have a BGM 177 kitted Stella and I went from the stock 20/20 to a MRP 30mm intake with a RD350 reed block, and a PHBH28 carb. Granted I also changed from a SIP road 2 box pipe to a JL/SIP performance expansion chamber at the same time, but I definitely gained 5-6hp just with those changes. It revs out more and the jetting process just makes a lot more sense.

Aren't those honda Dio reed blocks angled? I wonder if you'll have any issues with packaging/fitment. You may need to dent the frame a little.

Oh yeah, if you ditch the SI carbs you have no choice but to premix, as the oil pump is inside the stock airbox.

If that's an iron 177, it's entry level tunable. Tune for more mid if keeping the box or more power if changing exhaust.
If not modifying the cylinder, then the 24/24 is plenty for it as is.

Ive been thinking about figuring out a redneck way to flow test the Dio reed block against the stock Stella block.

I haven't even tried to figure out if the clearance would be much of an issue. My cowls are already beat to hell so it wouldn't hurt my feelings much to hit it with a hammer or cut a speed hole.

Right now though I have to deal with the fall out of hard seizing it last night.