Modern Vespa

Hey all. I can't seem to find the info I need, so I thought I should just ask.

Scootermercato sells a fork "pivot kit" for the swing arm of the GS160 or SS180, consisting of a large pin, a couple of business, pin rollers, washers and o rings of two sizes. But how does it all fit together? Even the exploded drawing/diagram seems vague to me... I'm talking about number 39, 40, 41... in the drawing below.

Does anyone know how to install the swing arm to the steering column of a GS or SS? It's a unique setup, so all the videos I have found on youtube are not relevant...Please let me know. Thanks.

Like that. The needle bearings and small o-rings go inside the pressed cups. Use lots of grease to stop them from shifting around. The cups may press in by hand, or you'll have to use a press of some kind. I don't have factory tools so I used what basic tools I have (sockets, extensions, bench vise, etc.). There should also be the larger o-rings installed (not shown in the photo) between each cup flange and each washer.

Here's another.

The smaller o-rings (42) go inside of a groove in each bearing cup (40). The washer (43) and larger o-ring (44) get sandwiched between the end of the fork leg and the bearing cups (42). The needle bearings (41) line up inside each cup (42). Use heavy grease to keep them in place. Carefully press in your old pin (39) past the inner o-ring as a guide from the right side. This will hold the bearings on the right side in place as you slide the new pin (39) in from the left side. Twist carefully past the o-ring inside the cup, don't forcefully push or hammer because you could displace the o-ring or needle bearings. As you push the new pin in, pull the old pin out. If you don't have an old pin, just be careful pushing the new pin on through. Use a screwdriver in the slot of the new pin (39) to turn it until the flat in the middle of the pin lines up with the hole in the end of the fork. This hole is for the tapered lock pin (47) to be wedged against. I hammer it in with a plastic hammer. Then #45 and and #46 go on. The tapered pin is what keeps the the main pin (39) from shifting side to side and eventually coming out.

Ah ha! I was focused on the column itself. It looks like most of the work is on putting the parts onto the swing arm. I will look at doing this today... Thanks!

Sorry, I meant to type: The tapered pin is what keeps the the main pin (39) from shifting side to side and eventually coming out. Not papered pin.

With your help, I see it is not very complicated. Thanks! One thing I just noticed, though, is that I am missing the washers (43), which I need to source. Do you happen to know if the specifications of these are critical in any way? What are they made of, and how thick are they? I wonder where I can get them... Thanks!

That's unfortunate. They should come with the kit as they are quite specific for this part. Maybe ask the seller if he has a set. Don't try to find something similar at a hardware store or you'll most likely screw it up. Make sure to grease everything well, but I would not grease the wedge pin (47), just tap it in dry until there are enough threads on the other side to tighten the nut down on the small plate.

Another thing to be aware of is painting. If you are going to paint, mask off the holes where the bearing cups press in. This includes the insides of the holes and even the area under the flanges of these cups. If paint gets in there, it makes it very difficult to impossible to press the cups in, and if paint goes on under the flanges of the cups, it messes up the tolerances when fitting the fork end in. In other words, you'll be struggling to fit the washers, o-rings, and fork end in because the paint is taking up space. This goes for the shock pin hole as well. If it's got paint in the hole, the pin won't go in.

Here are the measurements:
Inside diameter = 15.3 mm
Outside diameter = 25.2 mm
Thickness = 1.0 mm
The material seems to be black coated spring steel.

Putting the new pivot pin in the freezer helps considerably, and I used my long 10mm socket on the other side, also in the freezer overnight before doing the job.