Modern Vespa

Ha.... I thought I did Ginch 🤔

Only this photo is what I did post though:
LML 252 Frankendrak build (Post 2766835)

Edit:
What was ordered, and received for that matter is 22:64, straight cut. This was the shortest ratio available in a straight.

https://www.lavespadue.it/default.asp?cmd=getProd&cmdID=14926&idC=1066&idA=25&l=2

For the sake of cylinder knowing correct time a.k.a. clocking

I think this photo will make it clear, for all times, long Vs short sealing surface. I just don't get why sellers/manufacturer can't post a pic as clear as this. At least it's clear to me. 🤷🏻‍♂️

It does put a smile on my face though, cause there's a lot of material to remove. Need to make sure there's enough "meat" though.

This is what it looks like after applying some cover.

I'm gonna have to fill that void with some JB, unless I revisit the welder. Not likely, unless I want to self-inflict some difficult to match grinding experience.

This mark-up represents the opening from underneath, where the old pad used to live. Is this too much of an opening, in your experience?

On the other side of the manifold business, more printing success to the rescue. That's to save from poor decisions made months ago. 😁

Just as reminder, a PWK36 clone was chosen, and matching manifold. Carbie has a 44mm outer diameter while manifold has 40mm. Mismatch that needed resolving eventually.

Nice e mark up. You may well regret not welding that dent. Might seal with JB, might not.
There is no too big, however the clutch side of the inlet is thinner than it looks.
Open the inlet and match the cylinder base. If any hole welding needed, then do the inlet surface.

They do sell 44mm manifolds. Just expensive.

There's a hole that needs plugging, so I'm eventually go gonna back to see the welder. But I remember you saying in the lines of, cut what needs cutting, then weld what opens up in the process. So I may weld up that gap at the same time too, and all others which may appear.

Re. 44mm manifold, I guess the CNC one comes wider than 40, and yes, it's more expensive. Believe it or not, I didn't really like it, due to the internal 90deg "bend". The pics just don't show it well.
More importantly, at the time, I had no luck in finding what's the actual O.D. of the said CNC manifold, so I went for cheaper/more functional piece.

Moreover, I just finished "fitting" the crankcase+cylinder+exhaust combo, to mark the stud holes. That revealed a few things:
- I'm not sure I want to choose the stud holes based on SIP Road 3 exhaust, judging on quality of make. 😂😂😂
- VMC Explorer i.e. the port template may be a degree off, comparing claimed flywheel parallel-ness with position of the exhaust.
- I'm glad I listened to your advice on this step. One degree off is a lot, to fit an exhaust with such a tight fitting flange like SIP R3 has. I can only imagine what's it like with higher quality exhausts.

Pics to follow

So does the connector you printed now have a venturi where it narrows down?

Looks great! I wonder what size the stub is? Quattrini decided (inexplicably) that their exhaust stub was going to be very slightly larger than everybody else's, I wonder if VMC copied that as well?

The CNC manifold comes in a few sizes. Bend is fine. Really well made. And the carb sits lower. Is worth the cost not to reduce the size.

In fact you could print a manifold in that size! I've seen them printed and apparently work quite well. You would need to make up a holding plate a la Malossi that they use on their rubber manifold. I'll see if I can dig up any photos I collected.

Yeah, I follow the 3d printing scene, I've seen some great results. But to achieve, I would need a roll of something like PA-CF or GF filament. These are polyamide re-enforced with chopped carbon or glass fibre. That would set me back around 60€ just for the material. For a 100€, MRP sells their machined manifold, so was a no-brainer. If it was a 6-cyl engine, then printing a manifold would be much more rewarding.

Not really. The adaptor is just there to fill in the gap to a standard 44mm connecting rubber. It's slightly oversized on the O.D. and undersized on the I.D.

To answer this part of the question, stub dimensions, standalone is:
44.7mm O.D.
46.3mm height

But it does insert some 6-8mm into the cylinder + the thickness of the stub holding bracket + the height of the securing bolts. All adds up to usable stub length of 24.7mm

Seems like VMC went for the middle. Malossi 44.5 Quattrini 45.0.
I guess the exhaust you brought fits ok?

Very snug.

I was worried it wouldn't fit actually. Exhaust flange isn't cut through all the way to allow for actual tightening or expansion of the "flange".

And I think that the Malossi stub is pretty much the same diameter as stock?


Here's some images I've collected of manifolds, thought I had a few more. Also a link to AF parts. Antoine Fleury has been doing this for a while and this is one of his intakes (for Motovespa 160) which is made from TPU.

https://www.kytronik.com/collections/afparts/products/intake-to-use-phbg-on-motovespa-160gt


Also, I'm only showing you the yellow air intakes as they're so beautiful! They're made by Sking Louie on the GSF from PETG. Fitting on a smallframe where space is definitely an issue.

Saw that thing of beauty somewhere online, I guess it popped up in one of gazillion searches on the topic. 😁

Re. the choice of materials, I would never use PLA or PETG on an intake tract. Even for bits before the carburettor, cause engine can spit back and gas evaporates even when it doesn't (backfire). People can argue. 🙌🏻
- PLA has a relatively low temperature resilience, it will lose shape over time, under not even too high of a temperature
- PETG while more elastic than PLA, still isn't temperature independent, it can loose shape too
- Nothing(!) beats ABS and Nylon (PA) for the task. Otherwise, manufacturers wouldn't use them in the first place.

Well, that was a bit exciting, I must admit 😂

I bow to your greater knowledge!

(as you help re-tile the MRP swimming pool in a charming gold leaf)

Next project Ginch 👍🏻

And to answer my own stupid question, yes! 😁

No dice 😐

No matter what I do to the clocking, Explorer, SR3 and the P1 block won't go together easy. Need a bigger hammer...

Or go back to original plan. Allow the crank/rod/piston/port lineup to determine the cylinder clock, and then manage the exhaust can. Managing the can is bound regardless of cylinder clock position, I'd say.

Don't think that the exhaust should be the final measure of location, it's not uncommon for them to be out of whack, although not that much.

I have shown you this before, right?

Yeah G, the thing is, these are stock P2 locations, while VMC uses slightly different measurements. I'll pull it out of Fusion for confusion, but I remember scratching my head back in January. After all, I only have a case of one cylinder, so not much to base on first hand. Other than experience of others, like you lot who regularly post on this topic. Thanks for that. Beers, grogs, teas, sodas, etc on me. 👍🏻👍🏻👍🏻

I've seen Jürgen talk about the box exhausts, and how they're all over the place, and what can be done about it. At least that was my understanding. Also various reports in forum.

So there's a few things to try, but regardless, the springs are too short to reach. I don't know where SIP intended the springs to hook onto. 🙄 So at least those will need relocating, by means of welding.

I mean, if a production item needs so much work, then maybe I should have gone the difficult route and build a can myself... 🤦🏻‍♂️

VMC have to use the stock locations too...

Safis used these measurements to make a jig to put a 200 head in the lathe. He said the measurements were correct.

I used these when I was making the initial print of the PX1 to PX2 adapter. And they didn't match my cylinder, so had to remeasure mine. For an example, stud holes on mine are about 8.6mm instead of 9mm. Not a lot, but still.

Even then, my measurements were a bit off, angularly compared to P2 casting bosses, but under the premise of matching the VMC flywheel cutout:


I know this all sounds like I don't know how to measure, especially considering the results of cylinder timings measurements, but I have confidence that I'm in the ballpark, at least. Plenty of engines measured over time, etc, etc...

Let's see what happens next.

This vmc cylinder is likely to last a very long time. If you do make your own exhaust later. The actual measurements of other people's studs won't matter. I'd make it all fit nice and call it done.

I think you're on point.

I'm in the process of removing old bearings and dry fitting the crank with dummy bearings. I'll post pics of what comes out of it.

Today I finished what I started yesterday, which was dry-fitting the crank and piston, to determine the natural location of the ports. Hopes were had of an easy process, thanks to piston cutouts. Yet, life has different plans.

One learns from mistakes. I realised that as I pulled a chandlerman, and marked the ports upside down (piston facing the other way). So I let it go, and repeated the process today. Despite the hurdles, happy to have completed it, and now I know the location of ports and new stud holes. Exhaust can will be dealt with, in the aftermath.

Hurdles you ask? Well certainly, when one tries to combine three different aftermarket products. By difference, I refer to different manufacturers. At the same time, none of these were made for the case they were being put on. 😁 Let's say couple of thousands of words in pictures.

If in doubt... carve it all out.

Can't see it harming anything... taking the spigot hole right the way down will give you more crankcase volume so that cant ge a bad thing

Agreed. But as Ginch had pointed out, there's a risk of this happening if I go too deep.

Looks encouraging despite the setbacks. What are you using to enlarge the spigot area?

I used these, which looks exactly like what I have.

Went to friend's garage to try some grinding. He said he has aluminium specific burrs, which turned out to be just regular bits. Nothing a little wax can't resolve. Too much even, as some openings were made...

Oh damn! Trying to see the upside, at least it was not almost through without seeing it.

Some minutes ago, I'll remind you, you were looking into blasting. What was the outcome, as I'm in the similar pickle.

I did have a go. I don't know if it's my sandblaster, or the handpiece or the compressor, but the results were not great. I did see a diy thing to use the sandblasting cabinet to make a vapour blaster but am not keen on spending money on another thing I don't use because it's not very good.

Rikko


There are many places in the UK and some i am sure by Southampton that will do hydro/soda blasting for a very reasonable cost.

£20 - £40 for an engine : depending where you are in the UK

Look almost exactly like the chinese bits I ordered off amazon for my Malossi. Great tools despite the price. I'm sure everyone here already knows, but wd40 should be applied regularly to the bits to keep t°s down, and keep aluminum from clogging the sculptures. I found out the hard way

Also, regarding tire sizes, have you tried riding one of these with 130cm wide tires? (Sorry if I missed the mention in the topic). I had a 130/70-10 on an older P2 when the kits came out, and it was a big disappointment. If felt super clumsy, it was awkward as hell trying to lean into curves, and it seemed to attract every tack, nail, and shard of glass on the road. The only "upside" was that all the kids on gopeds would ask me how I got a typhoon wheel to fit on my old vespa

I'm sure mine are far-eastern too. Bought them 6-7 years ago, on a local flea market, got 6 for 10€. Gifted other 3 to a friend. Had them sit in various boxes until now. Served very well, I'd say. I used wax to lube them, worked like a charm.

Re. the tires, I don't like how Vespa handles. Many praise it for exactly that, but I like my bikes to be sluggish a bit. Gives me what I perceive as more precise control. So I'm looking forward to loosing some of that nimbleness, in the name of self-proclaimed stability. 😁

Moving along, roughing out was 99.9% completed yesterday. I even did some root canal surgery on the old stud holes, giving the welder more depth. Basically, I'm hoping he'll be able to plug the holes, without inducing too much warping on the spigot.

But, welder is on vacation, until next week, so until Monday I could only play with Autosol. God, I love that brand! I had nothing but success with it over the years. Dunno if you folks have it outside of Europe, maybe you lot down under. Today I tried their Aluminium Polish for the first time. Simply lovely.