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This, too, is why I got a PX

May 8, 2007

I’ve always said I’d take the PX to an Authorized Vespa Service Center for repairs while it was under warranty. This time, however, would be different. The clutch cable had broken, right at the pinch bolt. Luckily, I was able to make it home.

All major functions in a PX 150 except the front brake are controlled by cables. Occasionally, these cables break, usually at the most inopportune times. Given the scarcity of Vespa dealers and scooter repair shops, you will some day find you have no alternative but to make the repair yourself.

I concluded that it would be better to lose my cable-replacement virginity with the bike at home, in the garage, with all my tools handy. Especially since the clutch cable is the easiest one to replace. Also, the PX has almost 4700 miles on it, so there’s only about 1300 miles before the next scheduled service, in case I do the job poorly.

Seven dollars and change later, I return from Big People with a shiny new clutch cable and a pinch bolt (aka, solderless nipple), the latter being the device that maintains the tension in the cable.

Everything you need to have a working clutch

While the Haynes P-Series manual gives the impression anything slippery will work (even chicken fat in a pinch) Jeff said white lithium grease is what they use for cable lubrication at Big People. Any auto parts store will sell you a big tub of it, cheap; you can use it to lubricate all kinds of other things.

I started by removing the headset cover, but in retrospect, that probably isn’t necessary for a clutch cable replacement. Switching to the old-style mirrors makes removing the headset cover a whole bunch easier, since you don’t have to remove the mirrors from the headset mounts. Anyway, the photo shows what’s beneath the plastic, in case you’re curious. The clutch cable outer sheath is the light gray one on the left.

You remove the clutch lever by removing the underside nut, then loosening the Philips screw on which it pivots. Remember how I said you’d realize a tool you’d need wasn’t in your tool kit? In this case, it’s the 8 mm combination wrench you’ll need to remove the nut. Good thing I discovered this at home, instead of halfway between Port Gamble and Sequim.

With the nut and screw removed, you can just pull the clutch lever out. Be sure not to lose any washers; there was only one, on the upper side. I expected two.

Ever wonder what’s under the headset cover?

On the underside of the clutch lever, you’ll see a slot next to the larger part of the hole where the little cylindrical thing on the end of the cable goes. The cable goes through here, so separate the cable from the clutch lever. While you have the clutch lever out, clean it.

You can then pull the cable out. It’ll probably be pretty greasy; if you are on the road without some kind of lubricant (and there isn’t a KFC nearby…), there might be enough grease inside the cable sheath to keep it lubed until your next service visit.

Once the old cable is gone, you can put the new one in. Put nice big globs of grease on your thumb and forefinger, and coat the cable evenly and completely as you feed it into the hole where the old cable came out (a flashlight might be helpful for seeing it).

Gee, I’m thinking, this is going remarkably well. Then, with about a foot left, the cable hangs on something. Dang! Okay, don’t force it.

On the end of the outer cable near the clutch lever, there is a threaded fitting that goes into a threaded boss a couple of inches ahead of the clutch lever. This is an adjusting mechanism, which is intended for fine-tuning the point at which the clutch engages. I guessed this is what the cable was hanging up on, so I removed it (your fingers will work once you loosen the locknut; sorry, it was too dark to get a good picture of this).

I guessed right! The cable went through smoothly and was poking out the end of the sheath.

At this point, you need to feed the cable through the adjuster, and thread the adjuster back into the threaded boss. You did make a note of how far in the adjuster was threaded before you removed it, didn’t you? You don’t want it all the way in.

Next, pull a few inches of cable out. Take the little rubber bellows and slide it over the cable, slipping it securely over the threads of the adjusting mechanism that stick out on the clutch lever side. Then pull the end of the cable through the hole on the end of the clutch lever.

Now, go back to the headset and reattach the cable to the clutch lever, and the clutch lever to the headset. Be sure to push the cylindrical thing back, so the ball on the end of the cable is exposed… grease up the ball, and the little depression, then coat the cylindrical thing with grease. This will ensure smooth interaction between the cable and the lever.

Almost done! It’s time to install the pinch bolt, which actually is two parts. It will have a hole in the main body, into which you insert the cable. The cable is held in place by tightening the cap screw, which you do with the closed end of a 7 mm combination wrench (nope, there wasn’t one of those in the pouch, either… there is now). Hold the body with the open end of the 8 mm combination wrench you put in the pouch earlier.

There will be a lot of excess cable, so pull it tight… you want the clutch lever in its fully-extended position. Then slip the pinch bolt onto the cable and slide it all the way to the clutch lever. You can tighten the 7 mm cap screw finger tight, so it’ll stay in place until you get it snug with the wrenches. Jeff told me to get it tight, then turn the 7 mm wrench a quarter-turn beyond that. You don’t want to reef on it too hard, since you run the risk of slicing the cable.

Here’s what the clutch cable will look like when you’re done.

Check your work thusly: stand on the right side of the bike, squeeze the clutch lever as far as it will go, then kick the kickstarter as you slowly release the clutch lever. (Okay, I guess I need to remind you to make sure the ignition key is in the off position…) Once you encounter resistance, you know the clutch is engaged.

I personally like the clutch to be completely disengaged within an inch of clutch lever travel; gearchanges are faster that way. I lucked out and got it where I wanted it on the first try; if you aren’t so lucky, you’ll need to fiddle with the position of the pinch bolt and the adjuster until you have the clutch engaging where you want it.

All that’s left is to cut off the excess cable; you’ll need heavy-duty wire cutters for that. Leave at least an inch, maybe two. And keep in mind that over time, the cable will stretch, so you’ll need to adjust it.

I’m so proud of myself! 😀

There’s a Vespa Club meeting tonight. This would be as good an opportunity as any to road test my work. Favicon

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