Penulis
HOW TO ADJUST SELECTOR BOX ON VINTAGE VESPA
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| HOW TO ADJUST SELECTOR BOX ON VINTAGE VESPA |
One of the more tricky cable installations on a Vespa would have to be the gear selector cables. if the cables do not appear to be broken, but the shifting is weird or not working, carefully inspect the gearbox for damage (namely the selector arm as they may snap, there are more details on this below). You will need a 7 and an 8 mm spanner, two pairs of Visegrips (one needlenose preferrably), a set of cables and a friend to help. There is a single screw at the bottom of the flywheel that hold the selector box cover onto the engine. Undo this screw and pull the cover aside to reveal the Selector Box Parts. Tighten the slack adjusters so they protrude into the selector box.
Once you are into the gearbox begin by undoing the cable nipples using two small spanners. Pull the nipples clear of the box and set them aside. To replace the cables on a P series you will have to open the headset. To open the headset, undo the 4 screws on the bottom of the headset and lift it as much as you can without yanking on it. push the speedometer cable (large cable right near the front wheel) toward the rear of the bike and the headset cover will pop straight up. you should now be able to see the inside of the headset. Apply a piece of duct tape to the speedometer cable, just below the locking ring (the thing attached to the speedometer under the headset). Unscrew the locking ring and allow it to rest on the duct tape (that way it won’t fall into the fork tube). The headset will still be retained by wires. you can usually flip the headset back and work unimpeded, but if you know where everything goes, you may choose to unhook all of the little wires. There is a disc on the inside of the headset attached to the end of the gear selector handlebar. there should be two cables in this disc. These cables are the gear selector cables and they run down to the gear box. To renew these cables, carefully rise them from their seating in the disc and pull the cable straight out. Once one cable is out, replace it by feeding it down the same outer cable and then move onto the next, so they don’t get out of order at the gearbox. Once both cables are seated in the disc, set the handlebar so the dots line up. Don’t bother closing the headset yet.
When ordering new parts, request a selector arm and a new tapered pin, as the pin is likely to be difficult to refit. you will need a ballpeine hammer and a small punch suited to the size of the hole. You may also need a reamer (taper tool) suitable to the size of the hole. Start by removing the cabling and get the box into a well lit area. On a wooden surface, tap out the pin as per the top picture. It will fall out completely with only a small bit of force. Crank the selector arm far past the fourth gear position as in the diagram. with the pin removed, slowly pull up on the batwing and place the new ratchet arm on the shaft. Line up the holes and punch the new pin back into place as shown in the bottom diagram. The pin should go all the way in. If it stops, adjust the position of the selector arm on the ratchet shaft and try again. If you cannot get it in, use a small reamer to redefine the taper on the new part. Once you have reamed the hole a small amount, refit the pin and try to bang it in. keep adjusting the taper until it will allow the pin to fit snugly in the hole. Once you are done, refit the selector box and cabling (see above for instructions). Drain and fill your gearbox and replace the gasket if necessary.
The ratchet system should rarely need attention but problems can arise if the spring is deformed or the roller pops out of the ratchet arm. To remedy this problem, simply order new parts and replace the old ones. The ratchet arm is held in by a small flat headed screw. Uncrew the screw carefully and catch the spring if it goes flying. Replace any malfuntioning part and reverse the order of disassembly to fix the problem. The batwing is force fit to a shaft that is precisely positioned. if there is any wear to the batwing or ratchet shaft, replace both items. you will have to remove the small tapered pin on the selector arm to effect repairs to this item.