Modern Vespa

If you're talking about plugging the one on the top right of your photo, you'd need to check if it's outside of the manifold. If it's inside/underneath there's no issue, if it's half way under you might think about making a (say) 1mm thick gasket under the reed block that covers the hole.

You used to have a short sealing surface but now it's long.

Ha! Clever thinking... You're absolutely spot on, I can close the hole with a gasket. It's a blind hole anyway. 🤔

On the topic of surface length, my LML took a p**** enlargement surgery. 😁

Basically, what got me thinking is an impression that a short surface has the stud a bit closer to the edge of the case half, in comparison to long surface. So, if a enlarged the port area, the risk is that I'd open into the stud hole. Or maybe the hole is too close to the new stud location.

Basically, I think I'll just order the long one and wing it. 😁

I approve winging it 👍

If the gasket seals, it's not too big.

Well, that plan just went down the drain. Far-eastern manufacturing plant just quoted me 333USD for machining this wheel hub. It was just atop a 100USD, what, six-ish months ago.

Which co?

JLC today, PCBWay couple of days ago.
SendCutSend quoted me 1280USD for the same... 😂

Edit:
To clarify, two far-eastern ones were around 280USD for the production of the object, the rest is shipping. As for SCS, didn't go further through the process to find out the shipping amount.

BTW, I always wanted a mill... 😁

1280 is a good way towards it.... if you can PM me the drawing, plus tolerances ll see if my oldboy is interested.

Got to less than those prices

Indeed. 😁 At least towards an all metal (Alu cutting capable) desktop router.

PM sent

Visited the welder today:

Nice tidy "just enough" weld?

Blurred images, I thought it was my eyes+

You'd be happy with that? Looks pretty neat.

He managed to go in more than halfway through the old dowel pin hole. I'm content. I'll clean it up on the outside, once I'm happy with pinning. New pin will naturally be longer than the old one, but that's the cost of doing mods. I'll fill any gaps with the mighty ol' JBW.

For the other two spots, seems air tight to me. 👍🏻

Did you open the base transfers yet? Might need a little more weld to get well matched.

A friend gave me an advice.

The same person who helped with machining. He basically said that in his opinion, spending months of time designing and making a custom part (hinting at the wheel hub of my own design), which may not fit immediately while we're at it, is not worth the amount of money it costs to buy a ready made product. And I can't argue with that, other than saying things like, "I don't like the kits which are on offer".

Well, kits which were on offer, I should say. 'cause now, new kits are available, and they're far better priced. They're far better looking, but that's a personal opinion. Also come with certificates, which makes them road legal. I say a lump sum was paid up-front, but should speed up the project, so in the long run, maybe I'm saving?

No porting took place yet, but I'll be matching for minimum flow restriction.

Edit:
Don't think it needs more welding to match. I planned for it, basing off of a VMC template, so material was added where it needs to be. I also checked after machining, seems good enough. I'll post pics once I start chopping aluminium off...

Thars gonna look pretty

All very encouraging.

How are you going to drill and tap for the new studs? Is somebody going to do that for you or do you have a plan?

I'll post pics

I'm just guessing there will be some thin areas (holes) after the base matching. Cut where you need to then weld up any issues (holes).
Cylinder stud drilling is a pivotal moment in this project. Fit the exhaust when marking out. I'd be getting it done soon as; before the matching.

Agreed Jack221, but I can do it only after I order the can.
VMC did provide a template for port matching, but it also indicates correct clocking (and stud location).


Flat cut-off runs parallel with the fanwheel

One for you Jack221, how aggressive need I be with taking down these two corners (in blue)?

Get any 200 exhaust. Even a rusty oem exhaust (we've all got one somewhere). Even a degree off will be a tight fit.

The explorer is a touring cylinder. It doesn't work in the rev range where this makes a difference.
As long as it's as good as stock matching, it will be plenty good enough.

Harder than one would imagine, where I live. P2s are not native around here. What exists is imports, so very scarce. Easier to buy a new can. 🤷🏻‍♂️

Re. fitment, struggles are in the books, simply due to super wide tire I aim to fit...

Did you decide on an exhaust?

Also, I thought you said the authorities where you are (At Sea ) were very much against modifications? How do you deal with that with all the very obvious changes you're making?

Good question, although I'm not sure Triton will have much say about it.

Modifications are allowed here, in the name of safety.
With that in mind, I'm allowed to install a superior brake system from another vehicle if it fits. So I got a bunch of MP3 parts which I was using as a base. Left portion of the MP3 front suspension, to be exact. It was very interesting to see how close the parts match. There were a few ways to go about it, but the one i liked the most was to machine a custom wheel hub. We all know how that ended.
Another way about it is to fit an aftermarket kit, if it has homologation. In this case, German approval will suffice. This was chosen in the end, for simplicity and time saving.
Another example in the name of safety improvement is to fit a new headlight. A bit different re. what I can use. Like, I can't fit a headlight from another vehicle. But from the same model, I can, or aftermarket if it has homologation. Which is why I was moaning about that ill-purchased "stock" headlight last year. Homologation number is missing.

Luckily, my LML has plenty of safety improvement potential, so no worries there. Engine and exhaust mods, however? Big no no. That's where it counts for the scoot to appear stock. Which is why unfortunately I will most likely go for Road 3.1. It's not purely by appearance, but also by noise level.

I spent the last evening comparing Megadella, Sip and BBS. In terms of power, Megadella is a clear winner, followed by BGM BigBox Sport, judging by tests made by Freak. He tested them on an m244 with reed. I reckon, it's as close to my setup as I'll find online, so it's good'nuff. Numbers were like 34 ponies on Mega Vs 31 on SipR3. BBS was somewhere in-between.
Unfortunately, Megadella is just too loud to appear stock. Aside from that horn looking protrusion at the bottom of the box. 😁 It produces a lot of, if I had to put it in text, tang, tang, tang sound at idle, which I hate about two strokes. Also, I got the impression that it provided the least amount of clearance to rear wheel, something I need to pay attention to given the project trajectory.
BBS and SR3 on the other hand, produce that deeper doom, doom, doom idle note. A lot more stock resembling. I couldn't see how much clearance BBS provides, which makes the SR3 an obvious choice. Also, SR3.1 comes with O2 sensor bung, which makes things easier for me (I will be using O2 sensor for tuning). No other model discussed here listed it as included.
Freak did a clearance comparison for all boxes he tested, but clearance to rear wheel was not mentioned. BBS had some clearance to ground remarks and needed some reinforcement, however this was taken care of by BGM in a form of a version 2.

So this is where I'm at. Split between the two, power robbing boxes, and will most likely go for the cheaper one because of available information. 😁 Unless I whip out the exhaust calc and whack one can myself. Haven't done that in ages, and didn't really enjoy it last time 'round, so unlikely to happen.

Thanks for asking 👍🏻

With the 252 you'll be looking at 30hp min. With a proper expansion that number might go up to 35; the higher it goes the bigger the 4-5k dip. I think the box is worth it for fairly linear power. It would be nice to find a comparison that isn't FMP.

Jürgen explained nicely why the dip happens on resonating exhaust, and why it doesn't on box exhausts. It's all to do with the sound wave reflecting and travelling back at speed which doesn't match the engine cycle. In case of a box can, the lack of reflecting cone at the end eliminates the sound pressure reflection from this element, so no speed mismatch and therefore no dip. Naturally, because of lack of the same, less peak power is produced when the can comes on song.

I would love to have another source of information. Unfortunately, couldn't find a useful one. At the same time, I don't know of a motorcycle dyno nearby, which I can reliably (read affordably) use. In fact, don't know of any at all, locally. 😁

Edit:
Webcrawl to the rescue, I think I just found one, and not too far... 😁

There's this, a few years old now but fairly comprehensive and includes Road 3. Check out the proper expansion at the end.

https://scooterlab.uk/vespa-big-box-exhaust-shootout/

Yeah, saw your post on another thread I believe. I remember thinking they were pretty much all the same (or insignificantly different), having read the article.

Thanks 👍🏻

Sip Road 3.1 is on order in the end. I'm sure some performance will be left on the table, but that's a topic for future self.

So, while we're waiting for the parts to arrive...

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If you plan to install a wide tire, the whole engine will need to be repositioned to the right about 10~ish mm. It would be prudent to also extend the right side cowl that same amount, along with the upper rear shock mount.

Yeah, I've been warned 😁

Still have to finish those 3d scans I promised, which will reveal how much offset exactly will the 140/60r13 wheel need.

That's a HUGE tire! The tires on my 1980 civic were only 2" taller and about 5/8" wider. That car also came with 12" rims.

Quick math says that you'll have to move the engine a smidge over 3/4" to the right in order for the center of the wheel to be lined up in the frame. Of course same thing for the cowl and upper shock mount.

😁😁😁

Indeed.

Let's see how 3d planning goes, maybe I'll bump it down to 130/60r12.

Just hold off on choosing a transmission gearing until you decide on the tire size. With a tires of that big, you'll need to gear down low-low.

That's a bit too late whodats, gears were purchased. See the discussion starting here: LML 252 Frankendrak build (Page 8)
Somewhere mid-page

Pretty sure this is it but you don't confirm if you found the bits or not.
Btw if you want to link directly to a post, just hit the 'link' button up next to 'quote' and copy the url.

LML 252 Frankendrak build (Post 2764078)