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This is a nice looking cylinder. No info as yet, it's not on the VMC page as the pictures I found on FB had it labelled as a 187 prototype. Some fairly big transfers too.
It has an odd method of attaching the cylinder to the case, with short studs and sleeve nuts. Not really sure of any advantage of this system.
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Re: MHR 177 competitor? VMC Crono
Ginch wrote:
This is a nice looking cylinder. No info as yet, it's not on the VMC page as the pictures I found on FB had it labelled as a 187 prototype. Some fairly big transfers too.
It has an odd method of attaching the cylinder to the case, with short studs and sleeve nuts. Not really sure of any advantage of this system.
They stuffed a few ports in that cylinder. Could be interesting.
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Molto Verboso
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I imagine that it's a bit easier to get the cylinder on/off without removing the engine, and perhaps you could torque it down tighter?
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Lucky
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swa45 wrote:
I imagine that it's a bit easier to get the cylinder on/off without removing the engine, and perhaps you could torque it down tighter?
I'd say all of this, plus you can do things like check port timings under actual torque or pull the head for inspection without having to compromise the base gasket seal.

I tried googling around to see if I could find more info on it, but nothin' yet. Definitely could be one to watch, though.
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Looks straight out of a modern snow mobile or dirt bike 2 stroke.
Cool.
Have to say tho - not a fan of the cylinder bolts.
Had a carb manifold like this for a while on my smart carb.
Bolts would sneak loose - and were covered as these are.
No means to re-torque without removing the head.
They also eventually stripped the cases.
Studs were more secure.
Have found same with exhaust hanger bolt in the swing arm (old cases have a threaded hole and dont go all the way through).
Would be concerned for same issues with these head bolts - at least as a replacement on stock cases.
Love that exhaust port tho!
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Veni, Vidi, Posti
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UTC quote
Surely there's a way of holding them tight though? Spring washers? Think it's probably too small an area available to fit Nord-Locks.
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Quote:
Surely there's a way of holding them tight though? Spring washers? Think it's probably too small an area available to fit Nord-Locks.
Im probably just jealous!

That said - I wonder if they have struggled with that in testing/ will keep it in the end. Will be interesting to see.
Design looks very very cool to me.

Good find.
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60mm crankshaft and 110mm rod
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Veni, Vidi, Posti
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UTC quote
Nice find Christopher!

So that means reed only, unless you're willing to machine your case to suit a 200 crank, or grind the lip off your crank, or put a 200 rod on your 150 crank.
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I'm digging this cylinder. Since I'm old skool with the 60mm/110 con rod crank in my Stella cases, that doesn't put me off. I'm looking at the ports on it and my eyes are bugging out.

I'd also be a bit afraid of those tiny little sealing faces on the cylinder base, but maybe that's just me.

If you're going to run it on reeds, get a bell crank so it can get out of the way of the mixture flowing through the crank case, though.

Finally, it doesn't look like there's really any room on the mounting bolts for a washer, unless they're already on there in the photo's showing it installed.

Still, definitely one to watch and I'll be waiting for someone to find a dyno for it.
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chandlerman wrote:
I'd also be a bit afraid of those tiny little sealing faces on the cylinder base, but maybe that's just me.
Not just you I think!
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Lucky
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I was looking at this shot here. I know that a 2mm sealing surface *should* work, but that doesn't mean it *will* work as well as a 4-6mm surface will.
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Agreed on the anxiety level a 2mm surface would create, but I'm not sure you can even see the edge of the casting in that shot. It's kind of washed out. To me it seems unlikely that they would design it with such a marginal surface, but who knows.

Surprised Jack hasn't popped in here.
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chandlerman wrote:
I was looking at this shot here. I know that a 2mm sealing surface *should* work, but that doesn't mean it *will* work as well as a 4-6mm surface will.
I think it's more than that look at the bolt holes and boost port pictures.
⬆️    About 27 days elapsed    ⬇️
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More and better pictures. Plenty of meat outside the transfers Chandlerman.
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The more I see of this. - the more I like.
This is a bad ass cylinder.
The porting is reminiscent of Aprilia cylinders and other modern 2 stroke performance. There is really nothing else like it for a vespa.
Very cool.
Are these yet available?
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Which Aprilia is that? No word on availability that I've seen so far.
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Not sure which Aprillia.
That one was an aftermarket one for the Rotax engine from an aprillia as I understand it.

This link references the 122 and 123 Rotax motors - see port maps - looks similar.

https://hartrusion.com/en/aprilia-rs/differences-between-rotax-122-and-123/
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Bit more info, will add the pictures tonight after work.
Preparazione Vespa PX LML Star wrote:
VMC CHRONO MACHINED VMC C60 B110
I just closed the engine after the gearbox mishap.
The cylinder is the VMC CRONO in test phase that I remember to be a native kit in race 60 and connecting rod 110 so NOT a kit for P&P processing but a kit for geeks.
The exhaust has been worked on the boosters by breaking through the captive seat on purpose and it has been worked also on the central light.
The phases are original 179-119.
The head is not the one of the CRONO but I preferred to make one on the lathe starting from a STELVIO head because I wanted a more compressed head, squish 0,95mm.
The rack is much bigger than the STELVIO and together with a well worked exhaust recalls a big carburetor and a proper exhaust.
New Meteor flat head piston.
The shaft is a prototype not yet available of which I have already posted the photos, over 2kg of weight (!!!).
The crankcases are the usual lml star machined with prisoner moved.
Phbe34 and mrp pack with flow guide, unfortunately the vforce4 has broken blades.
The CRONO kit presents several interesting solutions such as the exhaust manifold that fits into the cylinder with an oring and flange that fixes it. In this way it is possible to easily make an oversized manifold.
The studs are short and tie only cylinder and Carter is no longer the head.
The head is recessed (2mm).
Exhaust lights with box boosters are "cautious" but leave room for heavy machining.
In short, a kit for those who want to have fun.
Completes my configuration fixed ignition ducati at 19° with 2.2kg lml flywheel but soon we will try one of 1.6kg given the heavy shaft.
Muffler for hour megadella XL. Primary 64/22 with Piaggio gearbox and fourth from 36.
Now the break-in begins but we will try several things in the coming months x complete the processing.
I will also try to make some videos that I will put on Youtube channel.

SO ULTIMATELY KEEP AN EYE ON ME!

Translated with www.DeepL.com/Translator (free version)
https://www.facebook.com/Stratocaster99/posts/883914228679264?__xts__[0]=68.ARAPcDoDPjuuFdxDHZsII-HE01_WF2yXVssJaJ4S6fRKWJ-JaET1uMO9jF8TOC3KfKxj5M7wNM1yaC5bkoDdqNtl4MRxGoaQ9M8FuUvGBHiitKe2haQkC2MuBj4sRy5KPNAROULeOjIKq7IGxLNgVoWNSDMahMkxaKSOXd9gIR-F8JS5EsCxSZU8QHDA18Jr3VAzb5dArkbUFDlyMIArKZVJaQhJ9S4iHoGHrxrQ9Lg4aTphOJoNECiTlb2e5fDv81j36N86cj1yxSyrziRf3P4nB15Cc-l2bYMsrcKBZfLwUJ52HcKXdyJO1Rg4NB0qZYQb2HNjEUDtn7PBTLPJzI0BANN3q6GO2XOXJWeXTo_7k_THtsR_Vg&__tn__=-R
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Interesting.
So it also requires a 110 crank - and seems to have fairly low timings.
Wonder why they are using a flat top piston - thought that was already adjudicated and decided as inferior to domed.
Thanks for finding!
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charlieman22 wrote:
Interesting.
So it also requires a 110 crank - and seems to have fairly low timings.
Wonder why they are using a flat top piston - thought that was already adjudicated and decided as inferior to domed.
Thanks for finding!
I'm guessing other things were more important in the design. If the head is matched correctly it's perhaps no big deal? You still get your MSV per the intended design. What's your take on the dome vs flat debate that you've seen?
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Preparazione Vespa PX LML Star wrote:
The exhaust has been worked on the boosters by breaking through the captive seat on purpose...
I can't work out why you would do this? And what's on the other side of the hole?
Edit: Another translation says "prisoner headquarters" rather than "captive seat". So it's open to the studs... not sure that helps with the why though.
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Jet Eye Master
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Going through to the stud on purpose from new is quite a statement. Does explain using the bolts even more. They must come with a gasket.
If this cylinder doesn't fall apart in a few thousand miles, it has great potential to go really well. Hows the quality look to you?
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Jack221 wrote:
Going through to the stud on purpose from new is quite a statement. Does explain using the bolts even more. They must come with a gasket.
If this cylinder doesn't fall apart in a few thousand miles, it has great potential to go really well. Hows the quality look to you?
I agree, sometimes thinking outside of the status quo and asking why can result in some interesting advances. The bolt hole is connected to the case and sealed by the cylinder on the bottom. Those are low pressure area so you could get away with a o-ring or seal of some type under the head of those bolts without an issue.
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I asked him why but he hasn't replied yet.

You would have to think that the hole would create a turbulent area that would slow flow through those ports... but maybe that's what he wants?
Or possibly he'll sleeve the hole somehow and gain a greater cross-sectional area? I really don't get it.
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Molto Verboso
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Just clicked through the FB photo's perhaps there is enough interference with the special cylinder studs with long shoulder which seals off the breach? Almost seems the breach is coming from the stud side maybe from stud machining. Wondering what they will do for carburetor.
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UTC quote
I don't think that's the case with the holes. Ports look widened to me. A friend had bought a used "old" Malossi 210 where they had gone too far widening the exhaust port and went through in one of the studs. To fix it up they pressed in tight a thin tube. Still works fine...
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Quote:
Acceleration test on 400 metres for the VMC Crono prototype for Vespa PX, output speed 126kmh!!!!

Engine description:
- LML star machined crankcase
- Prototype VMC Crono machined on the exhaust, stroke 60, 110" connecting rod
- Phases 119/179
- PHBE 34 + VForce 4 carburettor
- Ducati fixed ignition with 19° advance
- Megadella XL muffler
- primary ratios 22/64
The port work carried out... port timing still the same.
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Lucky
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UTC quote
Catching up on this thread, that's pretty damn good performance.

He doesn't specify what crank he's running, but I would not be surprised if it wasn't a P200 Bell, so 110 rod, 60mm stroke, which is what Rob Hodge put me on to when I first decided to go crazy with my BGM build and other than the part where the big end came apart a little and blew things up, it's been really solid.

I'm surprised he's on static timing, but did see where he has gone from a 34 to a 36mm carb.

I'd definitely take a look at this top end once it's on the market, but I think that my next truly big adventure is going to build something on P200 cases and see if I can get to "Kill yourself fast" without have a 50 page build thread like sdjohn
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chandlerman wrote:
He doesn't specify what crank he's running, but I would not be surprised if it wasn't a P200 Bell, so 110 rod, 60mm stroke, which is what Rob Hodge put me on to when I first decided to go crazy with my BGM build and other than the part where the big end came apart a little and blew things up, it's been really solid.
Yes it's a 60 stroke 110 rod. Not sure what he was using prior to this one, but this looks very nice. It's a also a VMC prototype from my understanding. He's saying that he's getting 11,000 out of the current setup. Impressive.
You need to look back through his FB page but he's moved the case bolt that's at the front of the reed opening on the LML cases, and opened up a path. Obviously a big job but means even with a full circle crank he has unobstructed gas flow to the cylinder. Don't know how much this adds to his hp figure but it surely can't hurt. Pretty sure he did this before Malossi brought out their case that has the same feature.

I also have the same crank as you in my BGM motor CM, and it's a really nice thing to ride. Probably need to raise the exhaust a touch for a few more revs.
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⬆️    About 3 months elapsed    ⬇️
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UTC quote
So now that this is out there and FMP is doing videos on it. I'm curious. It works without mods to a 150 case? Just need a cudgeon pin 15 to 16mm bearing?

Or does it require some mods to the case to fit the barrel and piston?

Out of the box its got 30.5 blowdown given FMP's measurements. This must have some wide power and torque with 116/177 timings.
⬆️    About 1 year elapsed    ⬇️
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Nedminder
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Since I am eyeing one of these up for my next build - I thought I would post up some cool findings.

Here is a Wiki page on the cylinder - timings, port shaping, etc. Pretty much everything you might wanna know: https://wiki.germanscooterforum.de/index.php/VMC_Crono_187

Below a few shots (found in the wiki) that show off the castings this guy did to determine the port shape designs. Pretty impressive.
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Ossessionato
P208, Stella VMC Stelvio 187, Stella 150, VNX1T, V9A1T, V9B1T, 02 Sportster XLH1208
Joined: UTC
Posts: 4110
Location: Staten Island, NY
 
Ossessionato
@swiss1939 avatar
P208, Stella VMC Stelvio 187, Stella 150, VNX1T, V9A1T, V9B1T, 02 Sportster XLH1208
Joined: UTC
Posts: 4110
Location: Staten Island, NY
UTC quote
That link suggests it's meant for p200 110 con rod cranks. Wondering if it will drastically affect the default port timings going with a standard 105 con rod crank.

Been considering trying this kit.
@charlieman22 avatar
UTC

Nedminder
62 VBB1T Round Tail W/ leaner sidecar
Joined: UTC
Posts: 4023
Location: california
 
Nedminder
@charlieman22 avatar
62 VBB1T Round Tail W/ leaner sidecar
Joined: UTC
Posts: 4023
Location: california
UTC quote
So I am pretty well read on it.
Here is the deal,.
It requires a 110 con rod instead of a stock 105 one.
The link shows all the possible timings - how nice - we should assemble this for other popular cylinders!
Mazzucelli is offering a 150 crank (60mm stroke I think) with a 110 con rod just for this purpose. All the usual suspects cary it so its plug and play.
You can also machine off the lip on a P200 crank.
Or you could press your crank apart and put a 110 con rod on it.
All three have been done - but the first two are the simplest.

All the guys say it is best on a reed valve.
Speaking of which - I need to find a set of LML reed cases I suppose...
@charlieman22 avatar
UTC

Nedminder
62 VBB1T Round Tail W/ leaner sidecar
Joined: UTC
Posts: 4023
Location: california
 
Nedminder
@charlieman22 avatar
62 VBB1T Round Tail W/ leaner sidecar
Joined: UTC
Posts: 4023
Location: california
UTC quote
Quote:
So now that this is out there and FMP is doing videos on it. I'm curious. It works without mods to a 150 case? Just need a cudgeon pin 15 to 16mm bearing?

Or does it require some mods to the case to fit the barrel and piston?

Out of the box its got 30.5 blowdown given FMP's measurements. This must have some wide power and torque with 116/177 timings
Since no one ever responded on this one.
FMP's numbers I can't make work on a calculator - so I am not sure if they are accurate from that video.
The link I posted has been up elsewhere and I believe it is the more accurate of the two.
No mods to the cases needed that I am aware of.
Conversion bearing can be used for gudgeon pin to rod rather than std. one.
⬆️    About 1 year elapsed    ⬇️
UTC

Lurker
Custom
Joined: UTC
Posts: 1
Location: New Zealand
 
Lurker
Custom
Joined: UTC
Posts: 1
Location: New Zealand
UTC quote
Here is a fb link to a highly modified LML Vespa motor with a Bell Crank, VMC Crono kit ported out, 35mm modified Flat slide carb.
Seized doing 125kmph
On going Vespa Hot Rod project.

https://www.facebook.com/vespalad69
VMC Crono 125kmph
VMC Crono 125kmph
125kph VMC Crono Dash
125kph VMC Crono Dash
⚠️ Last edited by VepsaRod on UTC; edited 1 time
@safis avatar
UTC

Ossessionato
1979 P150X, 1983 P200E, 1987 PK125XL Elestart, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: UTC
Posts: 4113
Location: Veria, Greece
 
Ossessionato
@safis avatar
1979 P150X, 1983 P200E, 1987 PK125XL Elestart, 1988 T5, 1995 PX200E, 2011 Yamaha Fazer 600 S2
Joined: UTC
Posts: 4113
Location: Veria, Greece
UTC quote
Nice work. Cases are LML though, not T5...
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