Modern Vespa

Yes!!

Congrats on the money burn…

I'm still waiting on the egig 170…

It's been like 3 months, but feels like forever…

Waiting on blowing up engines together!

Which carb you thinking of?

I would have expected a better crank than a Mazzi. I don't know which one you got but the "Uncle Tom" 54mm crank isn't too expensive and beats any Mazzi in terms of quality (made by Primatist)…

Oh that reminds me, did you buy another primary/clutch basket?

If I'm not mistaken the egig one finger clutch won't fit into a stock basket…

I can triple check, but pretty positive it doesn't because of the plates it uses

I looked at the Uncle Tom, but ultimately decided to wanted to full circle and, yes, I have concerns about the crank. But the step up was going to be about $400, and while it may turn out to have been a poor decision in hindsight, even I have my limits when it comes to turning money into go-fast parts. Well, if I do wind up needing a new basket, that's something I expect I can source domestically, so I'm not terribly worried about it at this point. And if I can't...what's another $30 in shipping at this point... I finally gave up on the egig. Waiting for it was a great way to procrastinate on kicking off this project, but I finally got sick of waiting and, assuming that I don't screw it up, this top end should give me some insane performance. It looks like egig parts are trickling back into SIP and ScooterCenter, but not the top end yet. I'm also a little hesitant to tie myself to such an irregular supplier, because if it's constantly backordered for six to nine months, you're going to wind up buying something else if anything goes wrong, which means a new crank, too, and suddenly you're back where you started, project-wise.

And of course, while ScooterCenter already sent me a tracking number, USAA decided to mark the SIP transaction as fraud, even though it was half the amount of SC, so I had one of those lovely "Bitte Zahlung freigeben!" emails in my inbox when I woke up this morning.

As to carbs, I'm probably going with either a PWK or PWM. Still need to read up a little on the PWM, but it's basically the newer iteration of the PWK.

I will probably start by stealing the PWK34 off the GL just to get some baselines, then size the the final carb based on RPM numbers I get from those tests. I expect it'll wind up in the 34-36mm range, whatever I go with.

I'd do a SmartCarb if I had another grand to blow on it, but unless unexpected good things happen to me in the next couple months, that'll probably have to remain a pipe dream.

Happily, SIP just sent me a shipping confirmation, too, so depending on the vagaries of moving things from A to B, I could be making the magic happen as soon as next weekend.

Made me chuckle… Sounds like a good choice… I did think about the small tank though… maybe it's not a problem?

Would be interesting on the pwm. Wonder if it's any good? Not convinced on the smart carb, I was nearly swayed by cm2 but until I see it in the wild, will probably stick with keihin and dellorto

It's that or cry about it. Given that running out of gas is part of my Personal Brand in the vintage community, I don't see any issues with the small tank in this scenario.

Most of what I've read about the PWM at this point is basically marketing. I'd like to find some discussion of it in the wild, most likely in the dirt bike/motocross world, I expect, and if they are liking it, I'll probably go that direction. Otherwise, back to my trusty ol' PWK. I feel like the smart carb is really intended for maximizing fuel economy more than power, although I've seen them show up in dyno videos of a couple of super-tuned motors of late, so maybe it just needs to get traction. Either way, I think I'm priced out of it unless Smart Carb want to start sponsoring questionable tuning projects.

"Hey CM2, I think someone is calling you cheap…" Good point… Jerry can it is!

Jerry cans are essential for smallframes

And largeframes for some of us...

My choice for carrying fuel are these products:
MRP bottle holder from Scooter Mercato (come in right and left side versions) https://www.scootermercato.com/Scooter-Parts/MRP
And Hundsdorf fuel bottles from SIP. (Come in 1l, 1,5l and 2 l versions) https://www.sip-scootershop.com/en/search/Fuel%20cansHundsdorf?model=eyJzY29vdGVyVHlwZSI6IntcIm5hbWVcIjpcIlZlc3BhIDEyNVxcXC8xNTBcXFwvUmFsbHkgJzU3LVwiLFwic2x1Z1wiOlwiVDZcIixcImRpbWVuc2lvblwiOntcIm5hbWVcIjpcIktMQVNTSUsgVkVTUEFcIixcInVuaXF1ZW51bWJlclwiOjIsXCJwb3NpdGlvblwiOjEwLFwiYXBpQ29uZmlnX3BhdGhcIjpcInNjb290ZXJcXFwvY2F0ZWdvcmllc1wifSxcImFwaUNvbmZpZ19wYXRoXCI6XCJzY29vdGVyXFxcL3R5cGVzXCJ9In0%3D&dim=2
I admit that I like gadgets and there are more cost effective ways to Carry extra fuel.
Just like how uncluttered it keeps things.

A storage/carry rack like that with a non-improvised jerry can looks like just the ticket. Gracias!

Accumulating resources...

My first smallframe build

mesmerizing vid very cool couldn't look away

Smart Carb - I like the quick to tune/ quick to tune to perfection nature.
Fuel economy for a performance engine is certainly good.
Im getting low /mid 20s HP with only 180° of exhaust duration and 175° of inlet duration.
On a rotary sub 200cc.
That translates to a lotta useable power band and grunt.

I suppose with time and some fiddling about - I could get a std side draft tuned in as well.
The state of tune itself seems superb - and that's part of the game that is easier to achieve with the SC.

CM2, you're the only person I know who's running a smart carb (and doing so quite successfully ), but I don't recall if you ever ran a PWK or PHBH...
Is the ease of dialing it in the main selling point?
How does it work to target 12.7:1 (max power) instead of 14.7:1(optimal AFR)?
Can you comment on ease of tuning versus "traditional" carbs?

Honest question, isn't lean conditions usually more power?

I mean, of course it isn't ideal when stuff overheats and blows up. But most dyno info, usually points to smaller jetting being more peak HP

Not according to Physics. I don't make the laws, I just follow 'em.

Yeah that's interesting. Wonder if there's a difference between 2 and 4 strokes?

Or it's a case of theory vS real world? Or actually Vespa engines are an anomaly??

The specific values for best economy and bet power vary by a LOT of factors, especially exact fuel type (E85/90/etc, octane, etc.) but the fundamental relationship is always going to be what it is, regardless of 2- or 4-stroke.

Also, if you think about it, inverting the relationship doesn't fundamentally make sense. How could less fuel produce more power?

richer mixes make max power until all the oxygen is utilized. if there is oxygen that hasn't been used, you have left power on the table. going further will just result in poor combustion of the additional fuel with higher HC and CO emissions.

John explains what's really happening better than I did

hell no, you had the chart there which says the same thing I did, I just put it into english. but yeah, oxygen utilization is key. mixing the fuel and air is critical, otherwise some fuel gets stuck in areas of the cylinder without oxygen (local rich pockets vs local lean pockets). there's a whole world of CFD analysis involved in figuring out charge motion.

Makes sense, but trying to get my head around it…

Another honest question, So 14:7 afr would be that ratio, that all the air is used?

Or is it that "air" is actually oxygen plus other stuff? And that theres more power with richer jetting?

air = oxygen + nitrogen + blah blah blah
14.7 is the theoretical ratio needed for complete combustion - the air needed to fully burn the fuel, but stuff like mixing poorly gets in the way. 12.5:1 is where most engines want to be to overcome those inefficiencies - you are adding more fuel to be sure you use all the oxygen. you don't want/need that rich for part throttle but you want it at WOT.

Prep work (i.e. further blowing the project budget) continues along with general planning.

I'm really struggling to find tires & (tubeless) rims right now. Normally, I'd go with Heidenau, but they don't seem to have restarted their scooter production lines yet, and every 2.10x10 or 90/90-10 tire I look at is either J-rated or not available.

So I'm open to tire suggestions on the tire front. I'm looking for at least an M-Rated tire, even though I don't think I'll hit 80 very often, I fully expect this motor will be capable of that with proper upgearing.

Finally, I went through that video embedded above and documented all the tasks, along with the bits he didn't do (mostly bearing installs) where I could see them.

Assembly Tasks

Interior build
1. Engine mounts
2. Kickstart buffers
3. Gear shift wishbone
4. Fly side main bearing
5. Fly side lay shaft(?) bearing
6. Clutch side
1. Main bearing
1. circlip
2. seal
7. Clutch side lay shaft bearing
8. primary gear
1. circlip (on basket shaft)
9. Kickstart quadrant
1. return spring
2. clutch basket base plate
1. spiral spring
2. kickstart gear
10. Axle+gear stack
11. xmas tree
12. Crankshaft
1. Pull into clutch side

Apply gasket sealer+case gasket & close the cases
Check for crank movement
Apply Case bolts

Top End Build
1. little end bearing
2. wrist pin & piston
3. piston circlips
4. base gaskets (if any)
5. cylinder w/ exhaust stub already installed
6. head gaskets (if any)
7. cylinder head
8. reed block+manifold

Clutch Side
1. crank spacer
2. drive gear
3. drive gear washer

Clutch
4. clutch basket
5. clutch base plate w/ springs
Compress clutch
6. plates
7. top plate
8. pressure plate
9. clutch cover

Rear Hub
1. Brake base plate (with shoes & cam pre-installed)
2. rear hub
3. rear hub nut

Final big parts
1. Stator+flywheel
2. Kickstart lever
3. Carb
4. Exhaust

Oh it's handy to buy that clutch basket holding tool and clutch compressor.

Using a rag definitely wouldnt have worked in my case, just not enough torque.

Depending on your clutch, especially tuned ones, the clutch compressor, because you have to install the plates inside the engine, and not compressed first, then install the pack. If that makes sense

It makes sense, and I already ordered both tools. And the one finger clutch includes the basket, so I think I'm covered there.

Meanwhile, I cleaned up the workshop enough that I feel ready to start teardown, then finished prepping the gas tank. It's ospho'ed and drying right now.

Then, since I think I'm going to ride it ratty to start, I cleaned off the number plate just because.

The entire thing was rattle-canned white, which has now yellowed with time. Acetone cut that paint reasonably well.

I'm still on the struggle bus figuring out tires, though. It has 3.0x10's on it now, but they rolled their last good mile many years ago.

I'm on that 3.00 buss too… I don't want to be grinding swing arm…

Today's update...the motor is out of the bike and teardown started. I would have torn it all the way down but...I don't have a smallie flywheel puller yet. *sad trombone*

Assuming everything stays on track, I will on Tuesday, though

And what would one of my build threads be without a video update?

Tank looks great!

It's the one you sent me!

Ah isn't it the same as a largeframe?

28x1?

Looked smaller. I guess I should check.

Most smallies are circlips, what kind of ignition is on there?

It looks like the OG points, but it had a circlip style nut. Looks like threads on the inside, though.

I'll take a closer look in the morning, but there was definitely no circlip.

I had a Malossi 19mm cone vespower on mine… was the same thread as a largeframe.

Searched on SIP, only saw the 28x1 tool pop up… not sure what other variations there are, but worth checking if the normal largeframe tool works…

One less road block

I just checked and my initial assessment was correct. Self-extracting flywheel. The circlip is missing and the recess was so full of muck that the nut drew what looked like threads to my needs-to-get-his-eyes-checked eyes. Once I worked it over with a pick, it was pretty obvious, though.

If I can find something that's close to a 25x26.9x1.2 mm circlip at Home Depot or Lowes, I'll be in business. Otherwise, it'll be time for a veeeery careful effort with a three-armed gear puller. I'm not going to use this ignition again, but I really don't want to damage OG parts like this getting them off, too.

Got a harbor freight? Depending upon the thickness, the 1 1/6" clip might work.

https://www.harborfreight.com/300-piece-internal-retaining-ring-assortment-67656.html

Ah crazy town, only found out how the circlip/no need for a puller system works…

The circlip is strong enough to pull it out? That has to be one deep ass groove!

Interesting the circlip is missing… PO never thought of removing the flywheel lol…