Lambretta Throttle Cable Replacement
This section shows a quick step by step of replacing a throttle cable on a series III Lambretta. The one in the photos is an LI125 Special which has a similar headset to the TV and SX, but the images will work for an LI once you've removed the slightly different headlight rim.
Remove the upper 2 small screws that hold the headlight trim to the headset. The lower ones can stay in place or you can remove them too for easier access once the headlight is removed.
On the underside of each side of the headset you'll find a single flathead screw that needs to be removed. This will allow the headset top to be removed.
Disconnect the small light for the speedometer which is a friction fit, and then push the speedo cable up from the front fork to get enough space to unscrew the speedo cable from the speedo housing.
Remove the left side panel to get access to the carb. The throttle cable is the cable shown above with the red arrow. Now remove the inner cable by cutting one end or the other and pulling it out through the cable outer which will remain.
New cables come in a variety of ways, but you'll need to have a removable part at one end or the other. I choose a cable that has a soldered nipple for the carb end, and a removable nipple at the headset end.
Thread the new cable in from the carb end after lubricating it in oil. You should have a fair bit of extra cable poking out at the headset end.
Connect the soldered nipple to the carb slide, and be sure the outer cable housing is well seated in the throttle adjuster as shown.
At the headset end you should have the inner cable sticking up at the throttle pulley. Your pulley may be a cast metal piece but should function in the same way as these later plastic ones. Try pulling on it to make sure the carb slide responds.
Find the top of the throttle cable outer and make sure it is seated in the metal stop where the arrow is shown above.
Fit the removable upper nipple in to the throttle pulley and thread the inner cable through the central hole.
Turn the throttle twist grip back to its stop and pull the inner cable tightly but not enough to move the carb slide. Then tighten down the upper nipple and test to see if the carb responds. If it is a little sloppy it can be adjusted at the carb adjuster, but if there is major slop in the response, you may need to do the previous steps again and tighten the upper nipple once more.
The final step is to clip the remaining inner cable at the nipple and use some grease on the cable and nipple where it touches the pulley . Replace the headset top being sure to reconnect the speedo light and speedometer cable, and you should be good to go.