need help - 2nd gear keeps disengaging

[pero]

As mentioned - only 2nd is giving me grief . What happens is it throws out of the gear into neutral when I open throttle to much or when I reach higher rpms. Sometimes toward 3rd but usually toward 1st.
I changed the cruciform not so long ago (500 km ago max) and checked it again few days ago - it looked OK(but didn't look on the inside). 2nd gear it self looked undamaged. Changed the cables (inner + outer) even reversed them (4th-1st, 3rd-2nd and so on). No change. I tried pulling up steep hill in 1st on full throttle and that went perfect - the same with 3rd. So what the f*** could be wrong ? I'm getting really desperate .

Forgot to mention - I can fill on the handlebar that it's moving and if I grip it really hard it's a litlle better but it will still pop out.

Pero

[pero]

I was just reading here web.ukonline.co.uk/niall.king/smallframes/engine9.htm
that it could be weak spring that holds 2 metal balls. Any thoughts on that ?

[hank]

it could be that, but was the cruciform you put in a genuine paiggio one? I know plenty of people have problems with pattern parts and i've been told to always get a piaggio one if possible, not always available though.

only other possible reasons i can think of could be the gears are too loose? - need shimming, damaged cogs? damged gear selector arm? the gear cogs were put back on the right way round?

[pero]

I don't think it was original one. Cables shouldn't be loose but I'll check and gears have no play (i installed 1st oversize shims). I'm afraid the arm could have some play in it. Ohhh that means more costs - damn.

[tony]

hi mate,
as hank says, shimming,cogs or spring etc. Make sure shimming isn't too tight however and one thing else to look for is play in the 6204 hub bearing,or bearing retainer (hub backplate). I've had this where the casing was worn depth wise and the backplate was not retaining the bearing..under load the whole shaft can move along its axis and jump gear-immediate soultion was to leave off the hub back plate gasket!
Recently a faulty batch of pattern selectors surfaced so always use a geniune one. Spring wise the taffy one is ok tho tends to compress and stay that way after a while. You can always put two bb's on one side of a standard one to preload it or use an uprated lambretta one but with spacers either end as they are a little short. The small clevis pin out of a prim front brake cable clamp/lever could of been designed for this purpose!