gear box woes!

[aussieriley51]

Hi there everybody, winter here in Australia so taking time to see why my 51 RMA...1.5...2nd gear keeps popping out...I've tight`ened up the linkages as much as i can even welded some metal on the front selector lever to make up for the wear but the instant i let my foot off the clutch 2nd gear drops out..very rare it will stay in all other gears are fine any thoughts would be appreciated cheers aussieriley51