Help with LD "floppy" gear selection

[skootaloon]

Hi All,

I have a 1958 LD 150. To help identify the model it has enclosed handlebars with a rectangular speedo with a chrome bezel. It has the tool "butty" box at the rear of the frame. I think it is a series 3?? but I maybe wrong.
The problem is that the gear shift is "floppy" ie you can select all 3 gears without feeling any resistance from the gearbox etc.
I have read up on the gearbox configuration and there is a spring inside the gearbox that should engage on the mechanism inside to provide a positive "feel" to the gearchange. The spring is in position but I am not sure if it is positioned correctly. My Lambretta manual says that the spring should be inserted into the hole with it's upper end towards the rear of the scooter. This will engage the spring onto the mechanism correctly. I have tried several times to insert the spring correctly and still have a "floppy" gearchange. Has anyone had problems with this before??
Also there is the adjuster on the side of the casing. Radial movement can be made to adjust the "mesh of the gears" according to the manual. I have taken this apart and there is an "eccentric" brass part which looks like it should have a pin through its diameter. How does this work.
I like riding the LD as it has a very "lazy" feel to it. My LD is ok to ride but would be more enjoyable if I could sort out the "floppy" gear change issue.

Any help would be great.

Regards

Simon

[Rich_T]

You're going to have to seperate the gearbox from the drive casing. Qute an easy job but you are going to eng up with a few cogs on the work top. When you split the case remember that the large allen bolt directly under the casing goes all the way through and is held in place by a nut on the other side. This bolt is actually ground like a dowel to improve location so it needs lightly drifting out if it is tight.

The adjuster you stripped down adjusts the pivot point of selector roller. This has the effect of adjusting the datum position of the gears so they correctly mesh. If you have removed this part completely it explains why you have floppy gears, as it should retained the lever arm by a split pin (which is inside the casing). The spring you described presses against the underside of the level arm that carries a roller (it is quite a hard push if the assembly is correct, if it goes in dead easy then something is wrong). The roller engages onto notches in the selector arm, the spring resistance to this gives you the characteristic gear change feel.

I think that you lever arm has fallen of the pivot point, it is held by a split pin and washer. It is a simple fix but only one that can only be done with the casing split. Time for you to swat up on your LD gearbox.

[skootaloon]

Hi Rich_T,

Thanks very much for the reply, most helpful. I know this thread was started a while ago, but I have only just got around to having a look. I have never worked on an LD engine and would appreciate some help on the sequence that I need to follow to be able to split the case to get at this lever that has fallen off. Looking at the engine I assume that the kickstart assembly needs to come off first??
I have an LD parts book and users manual but not really a proper workshop manual - are there any online to download??

Any help would be very welcome.

Many thanks

Simon

[Steve J]

The 'Lambretta Serviceman's Book' is about the best manual I've found, but I don't know of any online downloads. It's pretty unlikely that the split pin has come off the pivot pin for the arm which carries the roller, it's more likely that the coil spring which pushes the arm & roller against the gear selector arm is missing or broken, or that the roller has worn through its pivot pin on the arm. Check the spring first (hex head bolt next to the oil drain plug), but otherwise, as Rich says, it's a case of splitting the engine & transmission case.

[skootaloon]

Hi Steve,

Thanks for the info. I have found my old "Lambrettamans" service manual and it gives a description of the gearbox strip in there. It would seem that this can be done with the engine still in the frame, although it would be easier to remove the engine altogether. I have removed the adjustable part from the casing ie the rotary brass component, and there is no lever on the end. There is just a short shaft with a split-pin hole at the end where I assume the lever should be. The lever may be inside the casing, but as you and Rich say, the casing must be split to find out more. I am tempted to do the job with the engine in place unless if I can. Is it a straight forward job to do?


Cheers

Simon

[Rich_T]

If I were you I'd definately split the casing WHEN THE ENGINE IS IN the frame! it will be a hell of a lot easier. Wrestling an LD engine out of the frame is a lengthy job.

Splitting the casing is quite straght forward, don't forget to remove ALL of the casing fixings including the long bolt under the casing which typically needs a slight tickle with a thin drift to remove it.

[Rich_T]

BTW, you don't need to remove the kick start.

Drain the oil, put on stand, remove the rear wheel, remove the gear selector assembly, speedo (if it has one) and rear brake cable then pile into the cap heads that hold the casing together. Light knock with a mallet and it usually comes away fine (unless the chimps have beaten you to it and been medling before hand).

[skootaloon]

Hi all,

I have made some progress with the LD gearbox removal but have hit a snag. The engine is still in the frame and I have parted the gearbox from the engine about 5-6mm. The problem is that part of the gearbox casing (the part of the casting that houses the small spring) fouls the torsion bar part of the frame and stops full removal. I have tried tilting the engine forwards to try and get more clearance but still can't get the gearbox casing to clear the torsion bar.
I am almost there but need a little more help if that is ok

Any help would be very welcomed.


Cheers

Simon

[skootaloon]

I have managed to get the gearbox off of the engine after having to strip lots of parts off of the engine to get it to tilt forward more. The missing part ie the roller wheel and arm was lying in the gearbox housing.
Question one - how ever did it come off in the first place? (held in place by split pin and washer)
Question two - where is the split pin and washer???
I pass on both.
The gearbox is back on and the gears feel as they should, although I haven't ridden it yet.

Thanks for all you help.

Cheers


Simon