Moving this discussion over here from the NSM area, for more visibility and in search of a wider range of input.
Long story real short: I'm a motorcycle guy, but I was given a free basketcase scooter in hundreds of pieces, a Yamaha Vino 125, and in short order I had it running and roadworthy. Then my wife gave it a try and she fell in love with it, so I painted it and made it hers. But I had the bug, and I wanted my own scooter, so I got another basketcase with high hopes, this 2014 Stella Automatic.
When I got it, it was in mid-repair, and I bought it from the 2nd owner who had only had it a week and had absolutely no information. It was missing some parts that indicated the variator cover had been off, like the center stand spring anchor. Otherwise it read like something in the midst of diagnosing a starting issue: there was no starter solenoid, the original battery was there and totally shot, the spark plug was loose in the hole, the ignition coil was floating around in the engine bay. But it was basically intact and had a straight body and looked like it had only been laid down once with minimal damages, so I bought it for cheap.
I bought a battery and managed to get a generic starter solenoid fitted. Since it had horrible old gas in it, I drained the fuel and pulled the carb, cleaned it and reset it to factory adjustment as best as I could. There was a vacuum hose missing here and there so I fixed what I could and removed the air injection stuff, plugged the holes. Then I went to start it and began to discover what was really wrong.
Push the start button and you just hear the starter spin freely. I took the variator cover off and discovered the starter bendix had several chipped teeth. I figured this just was not engaging so I ordered a new one along with a handful of other parts that were missing. Once I got this stuff in, I put it all together, and lo and behold, once I managed to get the fuel reservoir full and the carb primed, it started and ran. And I rode it for about a week. Then it went very south and left me stranded, sounded like the starter spinning freely again.
This time I took it apart and it turned out the teeth on variator fixed drive face were sheared off. Further investigation shows that there was a spacer missing, which made it impossible to get the drive face tightened because the nut would bottom on the threaded portion of the drive shaft before it clamped the pulley.
I also noticed there is really bad wear on the bendix-side of the starter ring gear teeth on this pulley. So I need a new pulley, but they are not available.
I decided to solve the unreplaceable stripped pulley problem by using a combination of metal epoxy and roll pins to fix the kickstart drive plate to the pulley. And then eventually I solved the missing spacer problem with a couple of 15mmx20mmx0.8mm washers between the locknut washer and the kickstart drive plate. You can read the whole story in the other thread if you care to.
So now the core problem is that the starter will only engage about one in 10 tries. The scooter is not usable, basically. I got stranded on it when it killed the battery before it would start. I won't ride it anywhere unless the destination is back home now.
I have no good solutions on the table to fix this starting issue. Once the scoot is started, it runs and drives just fine. I need a new outer drive face, but SIP are out of them, and they seem to be the only place on earth who might one day have one. They have had them on order and they are over a two months overdue for delivery. I am not holding my breath. I am now considering trying one of two solutions, maybe both.
My current theory is that the wear on the starter ring gear is causing the bendix to not engage. It just kind of bounces off. So my idea right now is to remove the pressed-on ring gear and reverse it, putting the unworn outer edge towards the inside. Maybe this will buy me some time. So that's solution #1.
Solution #2 is maybe a better long term plan, since I need a potential supply of additional drive face pulleys, which warrants an engineering task. A pre-leader Vespa ET4 150 pulley has the right starter ring gear dimensions, 69 teeth, but from pictures, the eyeball test tells me the splined center interface is too large for the Stella. I measured the outer spline diameter to be about 14.6mm, and it's an 18 spline interface on the Stella. The ET4 pulley has an 18 spline interface, but it looks to be bigger than 14.6mm. Also, there's a recess for a spacer on the inside of this pulley, so a spacer or bushing would have to be fit there anyway. Both of these problems are solved in the same way, which is to get a sleeve/bushing/bearing which fits the gap between the pulley spline interface and the crankshaft, and fit another spacer/bushing into the recess to take up the rest of the space. Then I can solve the lack of spline interface the same way as I have now, which is to bond/pin a kickstart drive plate to the new pulley. So I plan to order one of these ET4 pulleys and give it a shot. But they come from China and will take until 2022 to get here, so I need a short term solution first.
The next problem was that I couldn't kickstart it. The kickstarter was siezed in the outward position when I got it, so I wound up whacking it with a hammer to move it, then soaking the pivot pin in WD40 to get it to loosen up enough that the kickstarter could be folded in and out. Then when I tried to kickstart it that day that I ran the battery dead trying to start it, the kickstarter folded back on itself because this pivot pin had slipped. Turns out that pin is a pressed in part. My penetrating oil loosened it up, I guess. So today I put a 3/32" roll pin through this pivot and the kickstart lever where it fits to keep it in place, and now I can kickstart it. It would likely take all day to kickstart it if it was cold, but if you start it once, it'll kickstart pretty easily subsequently.
My detective skills now are telling me that what likely happened is the PO cracked open the variator cover to replace the belt, likely at the 10K miles mark or so, and lost the spacer that's now missing, without knowing it. Then when it was all together, the drive face could wobble on the shaft, causing intermittent non-engagement with the bendix which eventually broke some teeth. I'm guessing the PO just described this as "it won't start" and started down the normal diagnostic of ruling out electrical start stuff and lost interest in the project. Then I got the thing, didn't know about this, and wound up riding it and eventually ruined the drive face running it loose.
There are a hundred other issues with the scooter. The seat cover was shot, so I made another one, which at least doesn't have holes in it, but it's not pretty. But I didn't want to invest in cosmetic changes until I got it to run reliably. The front brake light switch was stuck in the "on" position, and when I unstuck it, now it will only do "off". So I have a new switch on order, again from China and will be a while getting here. No matter, since now the tail light and brake light on the whole are not working, which I guess is likely a bad ground at the light assembly.
In the long run, I can't get along with the nutty angle the brake levers are mounted, and I also don't like the single mirror and the way it's mounted. Plus, I don't want to retrain myself to use turn signals on the wrong side, and I'm sure my wife will never ride this thing if the controls are not what she is used to. So I want to modify it to use regular motorbike hand controls, which means cutting off the cast right side control pod and finding a way to mount clip-on type handlebar tubes to the headset and fit ordinary hand controls. That'll fix all of my control issues at once.
And it has some bodywork issues, but the main thing is I need to find some matching paint. I can probably hammer and dolly the front fender into shape enough, but it needs paint on that part as well as the cowls.
Once this is all sorted out, I will deal with the normal stuff... headlight bulb, needs new tires, etc. But right now I just want it to be usable. It's a really cool bike and I hope to make it work long term.
There's someone local who has what looks like a potential parts bike donor 2014 Stella Automatic that I might be able to pick up for just a bit more than the cost of the pulley I need. So there's a chance I can rob the parts from a parts bike and be back in business in no time.
The biggest problem with this whole thing is that parts are just so hard to find for this thing. I hate to see a 90% functional, good scooter get trashed just over a $40 part. Plus, I like it, and I am not known for giving up.