gear problems vespa 180

[beefy]

Hi all
got a vespa 180 every time i put it in gear it jumps off then stalls it wont start off in any gear, i have changed the cruciform and bushes and seals is there anyone out there with a simple solution or is it a new gear box.? ps will a cosa gear box fit if it needs renewing,i have a px with 180 kit.
many thanks

[tooty]

had a P2 that used to jump out of gear all the time changed the little pin and spring arm mechanism on the selector cause they were worn and that seemed to fix the problem

[beefy]

cheers i'll give it a go got nothin to lose ;D