Modern Vespa

Hi Folks,

Newbie on this forum, so thanks for having me.

Just bought a 1980 Px150 and encountered a problem. When in 1st & 2nd she jumps out of gear. She's fine in 4th, getting there is the problem. I checked the selector cables and they seem to be fine. I removed the selector box and checked the grooves on the plate that cables connect to is holding the correct position (is that plate called a batwing?). My next thought was the cruciform, but then I noticed that the selector rod was loose on the threads by 3-4 turns. I am wondering if that would cause the gears to slip.

I looked at my Haynes and my interpretation of the diagram is that the selector rod holds the cruciform in place? Is that correct?

Anyway any help appreciated as it's giving a great weekend and I wanna ge in the road

Cheers in advance.

http://www.vespamaintenance.com/engine/cruciform/index.html

This page shows how the selector rod connects with the cruciform. It's probable that if your rod was unscrewed partially then the selector box wasn't really pulling the cruciform nicely into place, encouraging it to pop out. It's also possible your cruciform is worn... if it wasn't already, it probably is now thanks to it popping out of gear (which will knick it up).

For starters, get the rod screwed on nice and snug into place and just see if that solves the problem. It may well do that, although like I said the cruciform is probably a bit rounded now if it wasn't already. Anyway, if that doesn't fix the problem and you are sure the selector box is adjusted and in good shape I'd say it's cruciform time.

Hi there, thanks for the reply.

I'm hoping that tigtening the rod will cure my problem for the short term and I will change out the cruciform soon.

Can't get parts to readily in my local area.

keep in mind the gear selector shaft is reverse threaded so turning left will tighten it. its highly unlikely that its loose. you more then likely have a worn out cruciform. you should be able to order parts from the million scooter parts dealers in the UK.

Stripped her down today. Cruciform was in bad shape.
Rebuilding her tomorrow night However I'm unconvinced that it will cure my problem as I am never that lucky. Fingers crossed anyway.

Sorted

sweet!