Modern Vespa

Found this nugget at the shop this evening while rooting around for a Kajit stock check. No vendor markings, just a JAPAN stamp inside the skirt.

Skirt diameter measured out to 57.99mm with the good calipers. Pin measured 16mm. Pin center to edge of crown measured 35mm.

Any idea what it's for? Google Lens failed me, but it does look a heck of a lot like an RD350 piston.

was gonna say banshee or rz350 but wrong diameter

blaster is wrong diameter also

????

Hahaha. A simple truth.

Was the rd350 a58mm piston?

Actually, no.

An RD250 piston is 54mm. And RD350 piston is 64mm.

It could have been a 150cc piston swap paired with a 200/T5 crank for some kind of stock-plus setup, but I can't think of a Piaggio cylinder that had ports that could benefit from this piston. Somebody was experimenting, I guess. Just not sure what the full picture was.

The RD 350 and 400 are 64mm. A friend of mine has one.

Oops, you just beat me!

went through the whole wossner catalog and best match would be the earlier YZ125 in an oversize, but those have a shorter compression height (29-30mm)

searching for 35mm compression hight I find nothing even close.

Further googling by the piston marking seen in the last pic, "29N01" lead me to find an Indonesian cylinder with the same code. A cylinder pic showed an additional stamping of "135cm3". That's for a Yamaha RX-135, which I don't believe we got here. Maybe something else came with that cylinder?

A side car?

az, looks like you answered your own question with one possibility. 58mm yamaha rx-135.

neat looking 'ring-ding'. lots of cool 2-stroke stuff made for Asia we never got to see.

do you have lambrettas?

because this is how you get lambrettas...

all kidding aside, it *might* be for an old lambretta barrel conversion. I run a 190 that uses a Suzuki TC185 and I have another barrel that I think I set up for a KX or YZ it's been for-ev-errrrr so I'd have to look at the wiseco box that's with it on the dusty shelf.

p.s. kajiit thanks you for rooting around on them parts! I'll hit you back on the hotline!

Erm, this might be a bigger problem than anticipated.

1000th Post and I'm cracking on nonsense. So much for a milestone.

Got a fresh side of rings to go with it. Anyone feeling frisky?