Replacing the throttle cable

Vespas snap cables - fact of life. The throttle cable is guaranteed to snap just as you really need it, so inspect it regularly and keep a spare inner cable on the bike. Replacing the cable is actually really easy - probably one of the easiest jobs to do as long as it's only the inner you are replacing. The throttle outer is completely shielded from the elements so it should not need replacing.

First remove the existing cable from both ends, (I'm assuming it snapped, or why replace it?). Remove the headlamp to get at the cable in the headset and remove the tool bucket under the seat to get at the carburettor.

Grease the new cable inner thoroughly before you insert it. I find it easiest to grease a foot or so at a time as I am inserting it. Feed the new cable into the hole in the headset end (click on this picture to enlarge it, as it's quite difficult to see):

Hook the ball end into the slot on the throttle twist grip - look at the gear selector side for guidance - and feed the cable through until it is taut. At the carburettor end pull the cable tight and feed it through the adjuster (green arrow in the picture below)

Screw in the adjuster so it is almost completely in, but you can still slack it off a bit if need be. Slide the little brass cable clamp onto the cable and into the socket on the throttle arm (the red arrow). You need to position this clamp so the twisting the throttle at the headset gives little or no free play before it moves the throttle arm. To do this pull the cable tight, slide the plunger up till it is snug and hold the clamp in position on the cable. Now keep holding it while you slip the cable and clamp out of the socket (move the throttle arm to do this easily) and tighten the clamp with a screwdriver. Pop it back into the socket and it should be tight and snug - use the adjuster if necessary.

If all is well replace the headlight and toolbox, and go for a ride!