3rd and 4th gear

[smacmax]

hope someone can help just rebuilt series 3 125 engine new bearings and seals, everything went well except the spring and balls came out of the gear change mech. I got them back in ok and operated the gears manually to make sure it was going through from one to four. Now thats its all back together and running ok I can only select first. neutral and second gear.

[Knowledge]

Might I suggest you start by checking all the things outside the engine first?

A common problem is where the excess gear cable gets trapped when refitting the rear shock, restricting travel of the gear selector swivel.

Also, the concertina rubbers fitted to the exposes cable between the swivel and the cable block can get so hard, they stop good gear selection.

Check that the gear selector arm is not fouling on the rear suspension lug.

Also, make sure the outer cable has not come out of its position at both ends of the cable, though this might involve you removing the headset top, of course.

Good luck

[smacmax]

disconnected the cables to make sure there free and the handle bar control rotates freely through all numbers, tried moving the arm into the gearbox and it only goes 1-2 and is solid wont go any further even while spinning the back wheel.

[missing lynx]

Make sure the bracket that holds gear change arm is the right way round. And if you've bought an after market link bar make sure it's the right length

[HxPaul]

+1 Make sure the swival base is fastened on the right way around.https://www.ebay.co.uk/itm/Lambretta-En ... 0005.m1851

[dickie]

I've just rebuilt a gearbox 3 times. Yes, THREE times because it was extremely stiff in 3rd and 4th.

Turns out that the swivel was partially seized.

Check the simple things first. Cables ok. Swivel ok. Handlebar moving ok, swivel right way round?

[Ken Tucky]

If its of any consolation, and good you sussed it following advice on here, here's an old post of mine from a few years ago............

''Having been sprinting for many years and undertaking many/read - 'very many' gearbox strip downs you'd think that I'd have got the hang of it by now.
So if its of any help/consolation - about 4/5 years ago I was upgrading just about every moving part to do with gear selection in my sprinter, to remove any sloppiness.
I put a non innocenti gear selector - the part with the pawls on it, (not a selector cursor/sliding dog) in, brand new...................
I stripped and rebuilt the gearbox 29 times, I'm not exaggerating btw, because I either couldn't get fourth or couldn't get first and could not get the bell crank lever to sit in its rightful position in neutral.

I ended up putting my 'old', Innocenti selector arm' back in.

When I finally got around to checking this in another engine down at Chiselspeed's it was found to be impossible to build - it looks like the splines had been wrongly machined in the arm, so it was never going to build was it''.

Mr Tucky