Modern Vespa

Mine's red, but not that red one. I think those were photos from an early review article.

Here's mine:




You can also read my commentary on this whole story on my blog:
https://joshkarnes.blogspot.com/

Plus my other random projects, including mrs72's Vino 125.

There are more pictures, some before & after. I have recovered the seat and figured a way to mount ordinary motorcycle mirrors so they will work like on a normal motorcycle. Eventually I want to swap to normal motorcycle handlebar controls. But making the thing work is step 1!

I'm good at improvising for unavailable or non-ideal parts, but I don't have a machine shop in my garage. With the two scooters I have been working on, I am continually shocked at how little information there is on scooter repair and technical specs on the internet. I guess if I had been working on Piaggios... but comparatively, info on my Triumph and Suzuki motorcycles is incredibly abundant. But info on that Yamaha scooter was almost completely nonexistent.

Yesterday afternoon I went out to glue up the parts with Loctite Metal & Concrete epoxy.

When clamping them together, I discovered what is probably the root cause of my problem.

See this picture:


My scooter appears to be missing part #10 in the diagram, which the parts catalog calls "spacer". I suppose that part could be a pressed-in bushing that is in the center of the variator. But anyway, what happens is, when I tighten the nut, it bottoms out on the threaded portion of the crank before it pushes the outer drive face against the #13 bushing. This means the outer drive face will wobble. There's probably 0.5mm or so clearance. Guaranteed to fail. So whether that part is missing or not, I need some kind of thrust washer to take up this space.

I have a spare front axle washer for my Bonneville that will probably fit, so when I put it all together after I either get a roll pin added or fail at trying, I'll add it in. This should give the necessary clamping force for this whole assembly to work as intended. It is odd that the bushing appears to really just be too short for the job.

This is the kind of junk you discover with a basket case project that someone else abandoned mid-repair. There's a hundred things like this on my scooter.

Alright. The carbide bit came in today, and I went ahead and drilled and pinned the parts.

I put a ~1mm thick washer in place of the missing spacer. Then I torqued everything down tight, put It all together, and tried to start it. It's back to its old tricks, which now I think I understand a lot more about.

The bendix won't catch and hold the ring gear. It will occasionally catch and turn the engine like one turn, but then it lets go. I think the wear on the back side of the starter ring gear along with the increased space due to the additional spacer has resulted in the bendix not meshing well. Actually, my guess is whoever worked on this scooter before may have thought the bendix wasn't coming out far enough to mesh this gear, so maybe that's why they removed that spacer, to try to get the ring gear closer to the bendix.

The solution is probably to pull it all apart again and shim the bendix with a washer to match the spacing of the pulley. If I can get the bendix to mesh, I'm sure this makeshift repair will work.

TBD whether I have enough play on the cover side to handle a 1mm thick washer on the crankcase side of the bendix.


FWIW I did try to kick start it. It is un-kickstartable. Eventually I made the kickstart lever fold back trying to get it to start. It has enough compression that I can literally stand on the kickstarter when it's on the compression stroke and I have to jump on it with all of my 200 lb to get it to turn at all. Maybe while I have it apart tomorrow trying to shim up the bendix, I'll take the kickstart lever apart and see if I can cram another washer in there to keep it from folding back. But suffice to say, I think it won't start this way, not reasonably. Why on earth don't they put a pull starter on these things? That'd be a way easier to use backup starting mechanism.

I "fixed" it, got it all back together, anwyay. I wound up having to add a 1.2mm thick spacer, and 1.2mm thick washer between the bendix and the crankcase.

It has a new problem, surprise surprise. The bendix actually bounces off of the teeth of the ring gear most of the time and the starter just spins. But when it does occasionally catch, it will turn over the motor maybe once, sometimes it just does half a turn and sticks, then usually the bendix comes free again and the starter spins. After a whole lot of trying and draining and recharging the battery about four times, it finally got to where it would "run" for a fraction of a second while holding the starter button, but it didn't stay running.

My guess is a few things are happening. #1 the carb is dry and due to this convoluted vacuum fuel pump reservoir craziness, it is a bear to prime the carb. That reservior really needs a filler cap on it so I can put some fuel in to prime. And problem #2 might be that since no fuel is making it in there, the rings are getting coated with oil and making extra turbo maximus kind of compression that's hard for the starter to turn. Maybe once I actually get it to start and run, it'll wash/blow the oil off and get back to normal?

I imagined a good way to make that ET4 pulley fit, especially now that I have succeeded in pinning a kickstart drive plate to the pulley. I might be able to make up an adapter easily enough, like a bushing that fits into the recess in the inside of the ET4 pulley that has a smooth ID that fits on the spline shaft and then I just glue & pin the pulley and bushing all together to a kickstart drive plate.

NEVER SAY DIE! That's you and you got me hooked here, I WANT this stupid thing back on the road happy.

At this point, I'd think I'd focus on the Kickstarter which certainly should work. It's hard to believe it's never worked, and same for all others. Pull starter? I doubt it currently if 200 lb on the kick lever won't work.

This sticky dry engine you can't kickstart seems too much work for both you AND poor electric starter. So let's talk about that some more, your last post answered some questions for me.

When 2T ppl say it won't start, the first thing I ask is your plug wet or dry and yours is bound to be dry. I'd pull it out and squirt in a few spoons of gas and NOW kick it over for a while to flush things clean until it seems to free up. You should be also pumping oil where it's wanted.

Then I'd check for spark because it's so easy to do & kick over now and just to be SURE it's still there. A bit more gas maybe, install plug, give it some kicks and report back?

I actually got it to start several times in a row and went on a few miles ride through the neighborhood with no drama. Later my wife and I went out on the scooters, it was difficult to start after sitting just over an hour, kept feeling like either the Bendix didn't catch or came loose, sometimes it would turn over just a few turns then spin freely. But it did start. Then when we tried to get home again, it wouldn't start at all. Same shenanigans. Would catch and run for a second but not long enough to keep running, coupled with the Bendix not staying and eventually the battery went dead. So it's stranded and I have to go pick it up today.

So, the good: the pinned pulley is working at least to run the scooter once it's started. The bad? I think the Bendix just won't work with a spacer and the pulley teeth are too worn for it to work with a spacer under the pulley, and it won't tighten without a spacer under the pulley.

It seems like its a combination of three things. 1. dodgy Bendix and starter gear engagement, 2. Difficult cold starting, and 3. Battery is too small, and/or maybe bad starter ground wire. I can probably solve 2 and 3 but the reality is, I need a new freaking pulley.

BTW the kickstart lever is just a bad design. The pivot is a pin that's supposed to be pressed in. It slips when you put pressure on it, and allows the lever to fold back. I could try either red loctite the pivot in place or tap the lever and replace the pivot with a bolt. I think I'd still be there trying to start it if the kickstart lever had been working.



EDIT: I went over this morning and put the battery tender on the stranded Stella. Just now I went over to try to bring it home, it fired right up and ran all the way on the <5 mile trip home. Once home, I had to stop it and start again to get it up to the side of the house, and it did that bendix-bounce-off thing once then started.

Finicky little bugger. If it's absolutely fully charged, it starts ok. If you start it once, ride it not long enough to fully recharge, then it gets iffy starting again. It's like the bendix is not spinning fast enough to push the pinion all the way out.

Anyway, this is another issue than the pulley problem. Still needs a new pulley, but in the meantime I can probably sort this out and make it work.

Chances are I have at least a stop-gap solution.

I bought a 10-pack of 15x20x0.8 mm washers. I removed the spacer I had added that went between the tubular bushing and the variator drive face, and I put two of these spacers on the outside of the kickstart drive plate. The washers are needed to ensure the lock nut can be tightened enough to tighten the drive face without bottoming out on the threaded portion of the crank. The 15mm ID washer is just big enough to fit over the splines, and 20mm outside diameter is small enough to fit inside the pawls of the kickstart drive plate.

The goal here was to get the bendix to mesh more completely into the starter ring gear. My theory is that the wear on the back side of the ring gear teeth was causing the bendix to miss or skip off the back. So I had shimmed the bendix out 1.2mm, and now I am pushing the pulley in by some unknown amount vs. factory design, since there is a missing spacer of unknown thickness. I am hoping to get it to work for a while, long enough for a replacement pulley with fresh starter teeth to be found.

So to recap, the mods: 1.2mm washer in addition to the stock thrust washer under the bendix, no spacer under the variator drive face, 1.6mm worth of washers under the locknut washer, which reduces the clearance between the starter ring gear teeth and the bendix.

Once I put this all together, I had high hopes. I had not charged the scooter since I brought it home after it got stranded at my daughter's house, so presumably the battery was not "full". The first time I tried it, the starter just spun free like before. And it did the same the 2nd time. But the third time, it engaged correctly and I was able to give it some throttle and turn it over for a good 3 seconds or more and it started. I decided to kill the engine and restart it several times, and it caught and fired each time about 5-6 times in a row. That's with no time to recharge the battery. Good news.

I bumped the idle speed up a little bit and turned the pilot screw out another half turn just to try and make it start easier when cold. Then I rolled it down the driveway and started it again, went for a ride. Scooter ran great. I swear it is geared a little taller with that 1.2mm spacer gone. I rode it around for about 15 minutes then turned it off, started it again with no drama.

Jury is still out on exactly how reliable it is, or whether it will break again any minute, but for the time being it feels like a good stop-gap fix.

My dad is struggling to just make his '74 CL350 run at all, and I am constantly tinkering with my '92 GS500 because it always seems like something is less than perfect. This, plus the Stella frailty, reminded me just how miraculously perfect my Bonneville is. Man, they've engineered that thing right. And also, my wife's Vino 125. Never, ever a starting problem, not a single hiccup, just goes and goes and goes. And that doesn't even have the original carb on it, and was resurrected by yours truly with lots of guesswork and hacking. Something to be said for the quality of design and materials. But after riding around on the Stella, there's definitely a charm and fun factor to this rattly, bouncy old-school scooter that makes it almost worth the hassle.

Today I plan to go ride it a lot more, go on a good 20-30 minute ride to get it good and warmed up so I can dial in the pilot mixture and idle speed correctly, hopefully making it start easier. And I am going to see about using some red Loctite to fix the slipping pivot pin in the kickstart lever so I can at least have the option of kickstarting it should the spinny bendix pop up again. I have to get it mechanically sound before I get deeper into the more usability and cosmetic aspects of this project.

That spacer may have kept the two pulley faces further apart. When you moved the spacer to the outside by the kickstarter it allows the two pulley faces to come closer together and move drive belt further up. So it maybe faster. Part of tuning a CVT for top end speed is to make sure the belt moves to the outside of the pulley.
Sometimes the front needs adjusted sometimes the rear needs adjusted.

There a lot more to it but you can look up how a cvt works and tuning.

Thanks, and yeah, I understand the basics of variator tuning. I was just surprised that 1.2mm would make a noticeable difference.

Sad news is that my Stella won't reliably start. It's one in 10 tries at best that the bendix will catch the ring gear. I checked the charging system and cleaned the electric contacts, I'm confident it's not an electrical issue.

So the next thing might be to try to remove and flip the ring gear. It's certainly pressed on, the ring gear is steel and the rest of the pulley is cast aluminum.

And I'm going to get one of those ET4 pre-leader pulleys on the way.

Just to close the loop on this for those of you playing along, I am giving up on this scooter. It works, just requires some fiddling to get it to start, a dance with e-start, sometimes a little kickstarting, more e-start, etc.

But someone gave me a closet classic... a 2014 Stella Automatic just like mine but with only 38 original miles on it, been sitting for 7+ years. I am putting new tires on it and then it's ready to go, I already got it back to operational.

WHAT?

no pics?


PS If you were closer, I'd give you 100+$ for that thing. The first thing I'd try to do is adapt a decent motor cycle kickstarter lever and get the motor to reliably kick start if I could.



I made one for my Stella cutdown from an old Yamaha part welded to a steel Stella lever that is dead reliable and makes starting P210 motor easier than stock because it starts out up higher, but folds out of the way.

Maybe I'll post more pics.

The kickstart lever itself is reliable now. I put a roll pin in the pivot to keep it from slipping, so you can kick it all you want. And you had better want to kick it a lot, and put a lot of power into it, because not only is it hard to kick, but it is also hard starting when cold so it would take you a half hour of trying to get it to start with the kickstarter by itself.

So the routine is to try the e-start. Better than half the time, it catches and turns over just fine. Then it'll start! But sometimes, close to half the time, it will spin freely and then you just use the kicstarter to bump the crank a half a turn, then the e-start will work, probably.

In running, usable condition, even with the odd starting dance, I think I can get most or maybe all of my money back out of it. I may get bored and go ahead and try to put an ET4 pulley in it, and if I can make that work, then it will be worth probably double what I paid for it. I have half a mind to drag my feet on this until my wife forgets it's even there, then put knobby tires on it and go ride a bunch of gravel roads on it.

And how hard is your new one to kick over compared to the old one? The big question here it seems to me, is whether this crappy Kickstarter is just a problem only on your old bike, or is it a chronic design issue on these models. If it's the latter, I'd give up too, but if it's the former I might be hunting for the cause still.

It seems that motor turns over with great resistance which would also explain eating up the Estart parts . How well do things spin and work with the spark plug out, is it just incredible compression?

The new one is even harder than the old one. I can literally stand and bounce on the kickstarter without turning the motor. I feel like I'm going to knock the bike over kick-starting the new one.

It's just the design I guess. It's not like a px that you can kick it from the saddle. You have to be beside it.

Today I got the new Stella fully registered and legal. I put new tires on it the other day and "fixed" the speedometer, which is something I'll have to redo and finish, but apart from that and getting a seat cover whipped up, it's basically ready to go.

Which means the old one is ready to go to someone else, I think.

You might keep the old one for parts, as you've seen how hard parts,can be to find.

Yeah, I thought about that. I am just not 100% sure what I want to do with the old one, but that's an option for sure.

My wife has one scooter, she rides it routinely. I have two scooters now and two regular motorcycles. I already rarely ride my 2nd motorcycle, and I ride "main" scooter a lot less than my main motorcycle. I can't imagine the 2nd scooter would ever get ridden, so it will literally sit and let the fuel turn to trash in the carb and tank and collect dust and rust and passively degrade. All that while taking up space in my garage. As much as I would like the idea that I could keep it and do something cool with it that would make me ride it, the truth is, I probably won't.

So, once I get it back among the living, that is once I have two working ECUs for two scooters, I will figure out how to get it in the hands of someone who will use it.

FYI, I sold this scooter for what I paid for it last night. The buyer is a die hard scooter guy and I'm confident he'll put it to good use. It would have made me sad for this to be picked apart for spares..