Modern Vespa

Prelude

This one has been a bit of a slow burn. I've had it for over a decade now and I've mentioned it in the Smallframes thread. I've repaired a few smalllframes for other folks over the years, but this one keeps getting passed over. I don't have a particularly good reason for not having fixed it yet. Maybe I was worried about all the horror stories of SEA bikes. Maybe because I've found clues of those horrors while metaphorically poking it with a stick. I had other things to ride and I didn't have a line on early V9A parts. All I was lacking was a round-tu-it.

The resolution is the stake in the ground. It's been sitting around the garage and has been demoted all the way down to tripping hazard, so 2022 is the year when this thing rides.

Pedigree

It came to Tucson via Chiang Mai, so expect less-than-awesome surprises within.

Scope

This will not be a restoration. I'm just going to fix anything that makes it rideable and fully functional. I'm not keen on stripping it to bare metal, because I don't want to dilute what it is. I will scrub out the chassis and poke a camera 'round 'dem guts to see what shenanigans lie within.

I'm no longer married to the idea of putting only 1st series parts into the engine. I'm leaving it a 90 and a 3-speed; not particularly bothered by it being slow. Only real change I had in mind was to re-do the external ignition coil in a less dodgy way and put a proper needle bearing crankshaft in.

Status

So, here's where it sits now. Engine is out and stripped to the bare block. I talked a machinist friend into welding a small chunk of the crank housing back in which was originally held by a bolt and some glue. All parts were cleaned and I've been collecting spares for some time. I need to pick a crank and I'm waiting on a replacement 1st gear. Thinking about having the cases vapor blasted to see if I missed anything.

Pics follow.

The Gearbox

What's there to say? It's old and tired.

Axle shaft is battered but seems straight. It's hard to say, but the threaded section may have been welded back on at one point. I'll try to get a sharper picture. If it was fixed, someone gave more than half a shit when doing the deed.

Drive gears have clean, straight teeth, but the shift dogs for first and second are a bit rough. Second looks usable, but I sourced a clean replacement first gear. The shift cross is crap and the ears have rounded off. I have a replacement. I freed the balls; no aberrations so I'm giving them a clean bill of health.

Shift stirrup was pretty tired. I originally bought new blocks for the shift fork, but later noticed the linkage to the control rod is cracked and sloppy. Picked up a new shift mechanism.

Christmas tree has a banged-up keyway, but otherwise looks passable. I want to drop a fresh key in it and see how sloppy it is. I believe this damage is due to the clutch basket, because the cush drive is totally blown out.

I'll keep going through the assemblies as time permits. No secrets on this one.

Interesting project. It looks ok. Just replace the worn out parts and should be fine.

I bought my V90 in Chiangmai Mai as well several years ago. There are a lot more small frames up there than in Bangkok.

Nice 90! Cool look as is. If its solid. a good buff n shine and roll!

nice, will be following. smallframe builds are fun. I know others curse the carb location / adjustments but this is more than made up for by the nimble fun factor.

One of the few perks of the earlier smallframes is that they have a smaller gas tank and a bigger removable toolbox. Not a huge change, but that extra space sure helps!

OK, tried taking better pictures of the axle end in the sun. The bit of scarring and possible bits of metal spatter make me think it might have been welded back together, but it's far too parallel and concentric for a bodge repair.

Maybe I'm an optimist, but wait until I get to the handiwork on the crank and top end to pass that judgement.

As for this axle, what do y'all think?

can you mount it with a distance gauge and check runout? That's going to be your gold standard for usability, whether or not it's been repaired.

I'm gonna see a man about a reworked Yamaha cylinder head on Friday, and I'm sure he has the right tools. I'll report back on what we find.

That drive shaft looks like it's been cut and re-tapped...

Thank you for the reference, sir. Looks like I might want to shop for an axle too.

One of the problems with letting a project fester for a decade or more is that you forget some of the things you've done or bought to further said project. At one point, I bought a 1st series V50 engine (less crank and top end) sight unseen from a gent in Quebec. I'd have to dig the block out from under a workbench, but I think the serial was in the 5K range and I think it was a '63 model.

Crank aside, the rest of it was hardly worn and pretty nice. I couldn't bring myself to put the bits in my Thai V9A, so I cleaned the bits and boxed them up in case I ever found an early V50.

Today, I got a little ROI from it: I had an early axle to compare with. Yep, the V9A one is hacked.

The other weird bit is that I have 1.5 V5A early cases that have a "loose" caged needle bearing race on the flyside, with a race pressed into the case. On the V9A, I have a RIV stamped race with an oillite bushing installed that the axle rides on. Not sure if that's a hack or just a product change.

Nevermind, it's a bodge. Thanks for the reference, ScooterHelp.

Curiouser and curiouser...

It looks like 1st series smallframes used a K16-20-10 bearing on the flyside of the axle. Sourced and ordered a replacement bearing. Got out the torch and the slide hammer and finessed the bushing out of the OG race. The good news is that the race looks serviceable, so I think that's one less thing to sort.

Clutch Housing, Kickstart Assembly and Rear Brake

First, a confession: I'm not sure where the clutch is. The ears for the plates were pretty hammered and a stank of million year-old gear oil. Odds say I probably chucked it. If I find it, I'll share it. Still, I'm sure you folks have seen plenty of roached clutches in your time.

The clutch cover is passable, with a bit of scarring on the back from a poorly-mounted wheel. The brake drum has a locating PIN protruding from it's face and the rim has a corresponding hole. Small wonder the wheel wobbled and there were only three lugnuts. The clutch basket springs are toast and the pins are really worn. So, the cush drive doesn't just turn; it has front, back and side-to-side action too. In this grouping, the bodgery seems to be confined to the clutch actuator pin and the operating rod. The actuator, or lifter pin has a single leg on it instead of the two legged style found on later models and largeframes. The operating face is pockmarked and distorted where it interfaces with the rod. The operating rod is noteworthy for the weld bead laid down the lifting edge. I'm a bit surprised it wasn't filed back into shape; maybe the hope was that the extra metal would make the repair last longer.

Kickstarter hardware is old, but complete and usable. Just needed new buffers in the crankcase.

The rear brake plate parts look serviceable, but the brake shoes (not shown) were toast. I may have tossed them when the replacements arrived. The drum looks fine, But I have a usable spare (thanks eBay) just in case. The party piece here is the pin linking the brake actuator arm to the cable clamp: the linkage is held together with two nails, and one of them is broken.

The cooling and charging bit comes next. I need to find the crank in order to do the reciprocating bits true justice.

Received a replacement first gear from the mother country and a replacement caged needle roller bearing for the axle. I have the needed bits to start assembling the gearbox.

Need to select a roller crankshaft for it. I had purchased a Mazzy bushing crank previously to replaced the hacky original one and sourced a 1st overbore Asso piston to match a replacement early cylinder I'd found. This also means I need to swap the piston, since the piston pin bosses are wider on bushing cranks than bearing cranks.

Intake duration is a consideration. I've read somewhere that the intake duration on an early bushing crank is 101 degrees. Later roller crankshafts have a duration of 110 degrees. The 100 Sport crank supposedly has a duration of 121 degrees. Looking for that source to validate those numbers.

100 Sport does indeed have a long duration crank, don't recall the exact timing but it's in the 120s.

if somebody does actually need this info, let me know. I have 100 sport motor holding down the shop floor and I'd be happy to throw it on the bench and degree it.

Bingo! Found the data. At least in this respect, I'm not crazy:

https://www.scooterhelp.com/tips/parts/sf.cranks.html

Just in case the link expires, here's the relevant details:

Early Smallframe 63-65: inlet duration is 101 degrees
66-on Vespa 90 and Primavera: 110 degrees, probably includes VMA1 too
100 Sport: 137 degrees.

Now back to packing up the abomination.

That's lively for a little 100

Oh - that nail is spectacular.

In a bit of foreshadowing of my bodgery to come:
At 14, I got my hands on a mini bike - probably a sears model.
$5 from a neighborhood kid who said it didnt run anymore.
Wheeled it home and took it apart without a clue.
Managed to get running.
Front tire had no air.
In fact - had no tube.
So I used it like a run flat for the life of that bike.
Clutch slipped as well - and I had no idea where to get another.
So I put a long 10 penny nail through some holes it had - to lock it up - and just push started it from there forward.
I didn't even bother to bend it over - just "press fit" it with a hammer.

Still think how lucky I was, that thing never slung a nail at 4K RPM into my body - or head -
because - no - I didnt have a helmet either.

Georgia.
What can I say.
¯\_(ツ)_/¯

Minor bumpskie on this one too. I had decided on a "race cut" Mazzuchelli crankshaft for the motor. I prefer when they label it "anticipato"; it doesn't convey the grand vision of "racing" when there are far bigger 'n badder parts out there. I just figured it would get me a roller crank and maybe allow me to run a 19.19 carb more effectively.

It was another part shipment that went AWOL. I called the vendor and they listed it as delivered. The rub was that it was supposedly delivered before I had ordered it. As cool as precognitive parts delivery sounds, it's not reality yet. The vendor investigated my order and found it had been inadvertently shipped to another customer.

The annoyance is that customer received a freebie crank (they weren't returning the vendor's calls at the time of last inquiry) and I'm here, twiddling my thumbs, waiting for new stock to come in.

Might go back to the parts groupings pulled from the motor for the interim. Still waffling on whether or not I should have the cases vapor blasted prior to reassembly. The closest place offering that service is in Phoenix and I might be able to drop them off while I'm up there for work tomorrow. Kinda seems like lipstick on a pig, but it would make it easier to tell if it was leaking.

Received my Mazzy anticipato crank today. Measured the chord length of the intake cut at 78.48mm and a crank diameter of 86.87mm, so the duration or arc length of the cutout worked out to 129.2 degrees. Not as heady as a 100 Sport crank, but definitely improved over stock.

Took some measurements off an old VMA1 crank that's been loitering for some time. It also measured up as 86.87mm in diameter. The chord length for the intake cut measured 66.24mm, which calculated out to an arc length of 99.37 degrees; well short of the above-quoted standard for a '66-on non-PK crank but pretty close to the reported 101 degree duration of the early bushing cranks.

The upshot is that it'll take a better lungful with this crank and be slightly happier to spin at higher RPM. Now, I'll need to get a 1st-over '66-on V9A piston to complement the new crank. Did a bit of Dremel dressing to match the exhaust manifold to the cylinder and to match the intake manifold to the crankcase. Nothing earth shattering, just trying to ensure it doesn't get dusted by the Compact when they're both finished.

So, do I vapor blast the cases or just get stuck into building it?

Answered my own question. Just dropped the cases off at a Phoenix machinist for vapor blasting. Maybe it'll finally stop sweating funky old gear oil. Hoping to collect them later this week. If they look good, I might bring the Compact cases by for cleanup as well.

Verra niiice.

Only can go up from here.

Dropped off the Allstate motor for the same treatment.

it's so shiny it hurts my eyes.....

Oh man.
The promise of Uber clean cases.
Shakespeare wrote entire plays about them.

Curious - what is the going rate in your area to get em blasted?

Clean is good.

lovely... so clean...

I thought it might be cheaper, but they were pretty scuzzy. Cost me $125 all told.

Now I'll use gloves for a different reason.

Hoping it made Chris smile.

definitely vaderkleen.....

I pose the one to the brain trust; does anyone have a straightforward way to refit this little bastard? Can't seem to find a new one, but I've seen the part. Was debating taking it to my machinist to either roll the less-flared end out or make a tapered insert to pull the bushing over.

I have a rough plan, but I'm sure there's a better way.

I made a dilator way back but now I only use the newer type silent blocks and specifically the ones from Scooter Center (BGM)...

The dilator you show is a lot like what I had in mind, only I'd drill it down the center axis to pass a threaded rod through.

BGM might work, but I'll need to use this set:

https://scootersoriginali.com/products/vespa-reinforced-silent-block-px80-150-sprint-vna-vbb-bgm-pro

Dang early smallie uses the same silent blocks as a VBB. Might have to shorten the tubes a little, though.

Got my BGM silent blocks from Scooters O today. Looks like they will fit, though modification is required.

I will need to dress the flyside of the mount to allow the nylon spacer to fit; it was banged on at some point in the past and a touch out of round.

I'll also need to remove about 10mm off each mount's spacer tube; the old spacer is 190mm long and the new ones are 210mm in combined length.

Gonna see if my machinist can knock 'em out today; it'd be nice to see it start coming together.

There's a problem with these though. They're designed for the thicker engine bolt large frames have. The old tube has the "pinched" sections for the thinner bolt to center inside...

I did notice that after posting. I was thinking about getting some tubing and sleeving it. Need to get the bolt from the parts cache to measure before I order anything, though.

EDIT: Bolt is at the garage, on the floorboard of the scoot. Best guess is that the diameter is 10mm, while the internal diameter of the BGM mounts is about 14.25mm. Time to check McMaster...

Piston arrived today. Yeah, between bollox and this, it's a lovely Thursday. Pretty gnarly scar on the skirt. Debating either dressing it down or sending it back.

Nice throwback MP reference

that scratch should dress down fine, with a little light sandpaper. That being said, I'd still exchange it, if not too much hassle; just on principle. I want my new parts to be new, not damaged out the box.

I prefer to damage my own parts, as soon as I take them out of the box.

THIS EXACTLY