Modern Vespa

I don't think the decompression only goes with kickstart models, at least for US models.

In the US the newer LX, and LT, GT200 have the decompression but have no kickstarter.

Does the cam for the non-decompression setup have the hole in it for the mechanism? I'm seeing two part numbers for the LT125 cam 8459305 (without decompression it looks like, listing only shows 125 models) and 8459325 (listing 125, 150, and 200 models, most likely with decompression).

I'd be worried about rocker and pad wear if the decompression bit was just removed.

The cylinder head and camshaft that i used,are coming from a wrecked piaggio liberty 125 with only 2000 miles and without kickstarter.
I took apart the engine at the salvage shop with my own heads and i got suprised as you that the decompression mechanism was missing and i thought that something went wrong.
But we disassembled another engine like this and the dec mechanism was missing again.
So i started searching at the local piaggio wokshops and now i am sure that there is no such mechanism,only the two shims.

Electric starter,rocking levers,shaft,camgear,camchain,are the same for all models,with and without decompression mechanism.
But yes,the camshaft HAS the hole for the counterweight shaft even if there is no decompr. mechanism.
If i wanted to keep the mechanism i had to reprofile the camshaft with that counterweight shaft installed.

And this is the combustion chamber from the same philosophy air cooled with 2 valves head Honda XR200R next to the Leader's 150 chamber.
XR200 has inlet valve diameter 30mm for 66mm bore,or 45%.
Mine has 28 mm inlet valve for 70mm bore,not so good at 40%.
Honda's exhaust valve is 25mm and mine is 22mm.
It is impossible for us to put such big valves in our cylinder head.

HAHA! Yep, I wish I could have a ride too mate! Good to see the torque has improved very well too, not just the top end power.

Mileage is 5-5,5lt/100km with fast driving.

That's about right I rekn, for the power you have, and the likelyhood of draining the fuel tank as fast as your right wrist can manage!

The unexpected is the wheelie at the throttle opening after the traffic light turns green.

THIS.....makes me VERY happy!

I have my own little surprise too Dyna. After reading this thread I realised I can have the little aircooled scoot I have wanted for years, AND I can also have something with a bit of power and torque. Personally I love the GTS Vespas, but think them too big, I really like the Vespa LX and ET4, but I do a lot of riding on roads with loose gravel and small stones (and put rocks through 3 radiators so far, that's why I wanted aircooled........) and the paint would get scraped off pretty quick, so I had to go for something plastic instead.

Photo's of the new Sportcity One 125 when I get home in a couple of days! 8)
I already have the part numbers ready for ordering.........

EDIT: I forgot something!
Do you think this engine/bike/gearing combination is now able to cruise comfortably at 100kph if you wanted to? That is the cruising speed I was hoping to achieve when all finished.

Our 190 with upgear will just lift the front wheel off the line. Not much just a bit of "where'd my steering go" as you take off. Now I want to build another and port the head.

Polini upgear kit for primary transmittion+ET4-LX125 secondary+malossi variator with white contra spring and 12,5gr rollers+yellow clutch springs are ideal for vespa leader engine+200cc kit.
I start like a rocket at the traffic light and i have top speed more than i can handle.But if i want more top speed,i''ll raise the limiter,not gearing.

Aprilia sportcity has 14" wheels and different secondary gearing from vespa.Polini primary is okay for the beggining after installing the 200cc kit.If it is too tall,you can search for a different secondary then.
We can also calculate total gearing setting mine as a base according to the 118kg dry weight of the Aprilia.

I am really interested how the Keihin from Honda Thailand behaves with a simple 200cc kit,without modified cam,head and valves.
If someone try it,i would appreciate it if he could make a review for the final jetting.

This is a great thread Dyna, thank you.

When I blow up my second Malossi kit I definitely want to try the Liberty 200 jug.

Just to clarify, all I need is the piston, cylinder and Liberty 200 head gasket and it will all fit as per the Malossi 190 kit?

Once again, thanks for the best thread in ages.

Mark

Hi Mark!
All you need is the Piaggio cylinder-piston kit,OEM Part Number:844113 and some gaskets of course.

TADA!!!
Rode it home today.......


A bit of gravel where I live.

Hehehehe!
They're not quite that bad!

Hey Dyna, I kept forgetting to give you this link, for when a Zip 187cc Hyperscooter is starting to get boring.

For my own little project-to-be, I'm thinking 150 barrel/piston (it gets bloody hot here, my thinking is the smaller barrel/piston will have a lower heat loading when cruising in summer), and this.......
http://www.scooter-center.com/scoweb/pages/productdetail.grid?product=289211362173440&category1=A&category2=CAT&lang=en

Or maybe perhaps this......
http://www.scooter-center.com/scoweb/pages/productdetail.grid?product=289030599315792&category1=A&category2=CAT&lang=en

Apparently the aircooled and watercooled Leader cases are the same, they seem to have the same part number at least.

I'm hoping to have one on order next week. I just need to be able to get them on the phone to double-check freight and availability, at a time when they are awake and so am I. It's difficult when you live in the most isolated country on Earth sometimes!

Leader 125 has Bore x stroke 57 x 48.6 mm for 124cc.
A stroker 60mm crankshaft from "QUASAR" engine(Beverly 250,etc.) gives only 153cc with 57mm piston diameter of Sportcity 125.

With 70mm malossi piston gives 230cc.
With 72mm piston from piaggio liberty 200,gives 244cc.


But i am very,very,very curiοus about this mod.

And don't forget,if you use a stroker crankshaft,you have to machine a cylinder spacer to keep the same deck height and the right compression ratio.

Deck height is the distance from the crown of the piston to the top of the cylinder.You can't stack gaskets because there is a giant difference of 11,5mm between the 2 crankshaft's stroke and the many gaskets are not stable.
A different way is to machine a shorter rod or a taller cylinder.

You'll also need a good dial gauge to measure the deck height and 4 longer case studs.

Last edited by dynagrego on Wed, 07 Nov 2012 19:48:30 +0000; edited 1 time

Other things to consider in a long stroke crank:

The QUASAR engine runs the stator in an oil bath, not sure the bearing and seal surface is the same as the LEADER
Mean piston speed goes from 16.2m/s to 20m/s at 10,000rpm
Adding displacement without adding valve area is going lower the RPM but not give much increase in power

I spoke to them last night.
The crank is modified to fit into the Leader cases, so takes all Leader parts. I was thinking of using the stock 150 62.6mm bore in combination with the 60mm crank throw for 185cc. Pistons with different pin heights can be used to help with deck height, they don't have to be Piaggio, just decent quality (Wiseco, JE, etc), and there are 5 different pistons in 63mm if I need to.
The Malossi kit seems to make plenty of power without changing valve sizes, so I would expect the stroker crank to do the same, but with a flatter torque curve. I don't want extra revs for my motor, just extra torque from the capacity increase.

Adding 11,4mm to our stroke will make the piston travel 5,7mm higher and 5,7mm lower in the cylinder so the piston has to be about 5,70mm shorter to keep the same deck height.Is it possible?

It's not difficult to machine a spacer,there are some sites that you can send them a cylinder bottom gasket and ask to make the same from aluminum 5,7mm thick or something like that because we have to calculate and add the thickness of 1 more bottom gasket.
Or you can order it on line:
http://www.manufacturelink.com.au/content/cnc-machining-network.aspx
http://www.emachineshop.com/ They also give an excellent and easy to use CAD software for free.
You can use pistons of several diameters then.

Something else about the possibility of a cylinder spacer:the camshaft chain has to be 11,5mm longer,right?

Yeah, longer cam chain.
This crank is supposed to be a drop-in, that's from the guy at Scooter-Centre I spoke to last night. So if the throw is longer, and it's a drop-in, I would only imagine the rod is shorter.
We won't get into the whole "long rod vs short rod" thing here, it's bad enough trawling through page after page of crap elsewhere, but realistically the increase in bore side loading from a shorter rod isn't all bad, it has a small effect on bore wear but not much really. But anyway, when all is said and done, I was informed the crank/rod combo is a drop-in, using standard piston types.

I thought at first that the extra throw, combined with a better head airflow, would give a nice strong flat torque curve, making it easier and nicer to ride. But my little scoot as it is now stock, sits on 80-85kph true speed all day (95-100 on speedo), so I really only need an extra 10kph and I'll be content. I ride at 2/3 to 3/4 throttle and that is it's happy cruise speed. It would be great to lift the front wheel at will, but for me I'm more about just adding another 10kph to the real cruising speed.

I'm even starting to think I can get that with just detail work on the head and squish clearances, maybe a tuned (I make them myself) exhaust and jetting to lift the power up 10-20%, then just play around with variators/weights and clutches to pick up the extra 10kph.

My head is spinning from all the contradictory comments out there about the Polini or Multivar options for extra cruising speed. Really I'm not interested in how slow it accelerates, I have a dragbike in the shed for that.

Dyna and Oops, have you tested both, or is it just a choice between "favourite colours" between the two?

I would love to see a 278cc air-cooled Leader though....... 8)

Shorter rod?
I even thought of a shorter rod!
If rod is shorter,i am interesting too.
But how a Quasar crankshaft,a connecting rod and a lot of machining cost only 140 euros?Crank costs by itself 400!
http://www.piaggiospares.co.uk/spares/partImage.asp?GPN=Z%3D978%3D8%3A556&uid=0

I chose the Malossi variator after studying oopsclunkthud useful tables:
LX190 Testa Rossa
Malossi shortens a little the polini primary with LX125 secondary and now gearing is perfect for 200cc torque.

Regarding variators, I split tuning the transmission into 3 areas.

1. Geometry: Anything that changes the drive ratio anyplace in the system goes in this bucket. Gearing changes, tire size, variator, ramp, roller/slider size, belt length... All of these shift the ratios in one or more areas of the transmission. I aim to max out the variator at my estimated top speed at the max power RPM. Any time I change one of these the "tuning" starts over.

note: in my experience the mallossi variator has less range of motion and the polini has more when compared to stock. The angle of the ramp plate accounts for most of this.

2. Clutch (0-10mph): I normally don't bother but if I did I'd only be looking at the RPM from 0-10mph. After that it's all variator.

3. Tuning, balance the forces: On the simple end of this is just changing the roller weight to hit the target RPM but it can also include changes to the contra spring rate or preload.

TADA!!! There it is! The most succinct comparison I've seen, and one I can recognize at an instant.

Thank you lots Mr Oops! I was going to go for the stock variator coz I wasn't sure if teh aftermarket ones are THAT much better, just do rollers/sliders/belt and springs, but a higher ratio ramp variator (for more speed) is nice to consider.

Much appreciated Patrick.

Also the ramp of the LX150, GT200, and GTS250 are progressively flatter with the LX being the steepest and the 250 being the flattest. The roller diameter that goes with each (19, 20, 21) offsets this.

ie. LX has steep ramp and small rollers, 250 has low ramp and big rollers.

So basically (for a variator-challenged mind like myself!), the flatter the ramp, the more torque it can handle without overheating either the sheave or the belt?
And the Polini, due to the widest ramp ratio between low and high, has the "potential" to have the best top speed combined with the best acceleration?
Do you know if the Polini or Malossi variators have a greater diameter than the stock one (for more potential top speed thru gear ratio)?
I would have thought the best possible top speed or highest possible cruising speed, would come from the highest variator ratio (belt sitting furthest away from shaft) the engine power will turn, all other gearing being constant. Does this sound about right?

Thanks again Patrick, and sorry Dyna for OT thread-pinching!

I'm ringing the crankshaft guys again tonight to double-check a few things, then probably put an order in. Apparently they have stock in mid-December.

all the variators I've seen are the same diameter so any gearing increase comes from pushing the pulley halves closer together. A flatter ramp moves the pulley half less giving it less range from it's low to high ratio. Normally the top speed ratio is about the same and the difference is taken off the bottom. The bigger the engine the less you need or care about the loss of range.

A steeper ramp will also require heavier weights but since it changes the geometry you'd be back to adjusting the weights anyhow.

It's not clear to me what effect the ramp has on the general shape of the speed/rpm curve. Can't just noodle it out in my head and haven't had the time to test it out.

I always make several marks with a fat marker on the half pulley to see if the belt climbes at the highest point of the variator.If it does not,that means i need heavier rollers.Malossi and piaggio variators push the belt up to the same top point.
The variator of the picture belongs to my 50cc hiper4 engine,the original zip50 motor.
If you finally be satisfied,i''ll follow you.It's a pitty that the small valves don't let us fly too far...
If someone else port his head,my advice is to polish the inlet's surface like a mirror,we need to help air velocity to fill the combustion chamber as much as we can with mixture,because of the big displacement and the small intake valve.

Sick psycho project:
I wish i could find a way to modificate malossi 4V L/C head and make it A/C.

It's doable, what's your budget?

I've been working on a 2T head, 3D printing in wax and then investment cast. The design of the 4T would be harder but the cost of casting should not be more. IT would need more machining to finish but it looks like you could pull that off. For that mater, you could also try and do a DOHC if you can find a motorcycle to borrow parts from.

Yea new guy here trying to get an understanding.
This is a fantastic thread and answered some questions but their is a lot more I need to learn before I start this upgrade.

So is the Liberty 200 the same as the P200 or PX200?
If so would the Malossi 210cc kit for P200 fit as well?

Just making plans for the ET4, after I am done I might put in to an ET2 chassis and surprise a few people, lol.
I guess all I would really need to do is change the 150 badge to 50.
Let me know,
Thanks.
Mega.

Very interesting!
Turbobusa.net starting to look like a site for cooking recipes.

Unfortunately my budjet is small for casting a new head,my life sinks into the abyss of the crisis.
Anyway i was thinking (in theory),about shaving a 4valve malossi head and welding fins on it.It is more a crazy technical conversation,not something i have to do next weeks.


@MegaTitaniumMan
Liberty 200 is 4 stroke,P200 is an old 2 stroke.You can find many informations on the web and google about them!

Thanks dynagrego,
I just found that out from a few pics, 4 stroke cyl don't have holes in the sides.
So its looking like the only place to get the 200 cyl is not in Canada, its looking like they were not offered on this continent even.
That just means a bunch extra in shipping.
One other thing I looked up is 200cc is 12.50 HP (9.1 kW)) @ 6750 RPM
ET4: Horsepower (bhp): 11.3 bhp
I don't think that going by this stats it would be worth the effort, 1.2 hp gain?
The GTS 300 has 22 hp I believe so though its heavier it might be a better solution.
Correct me it this info is incorrect in any way as I would rather keep the ET4 and get some more fun out of it but for just one horsepower its not worth the expense. I could put a nitrous kit on it for less money and get better results.
Mega.

Yep, the 200 AC is only 12-13HP, only 20% more than the 125cc. But the TORQUE is MUCH higher, and with peak power at only 6750rpm standard, the engine would last forever. The Malossi 190 kit by itself, no other changes and everything else stock, would only make slightly more power than this, mainly due to the lighter piston, better heat transfer of the alloy cylinder, and reduced blowby from performance rings, but probably still only 14-15HP.
If you need more power you need to look at the things that feed the airpump........intake system, exhaust system, and the head. The liquid-cooled Leader 125cc in the Sportcity apparently makes about 10kW compared to the aircooled 7kW, bore and stroke are the same, the extra power coming from better head flow, a few more revs, and more efficiency.

Dyna, I think another way to get a performance head on the Leader may be to check head/cylinder bolt spacings on a few aircooled cylinder/head combinations from other engines, and adapt the whole top end from the barrel up onto the Leader cases, sort of like putting liquid-cooled Rotax top ends on old 2T Vespas. You could even adapt something by making a plate to bolt to the case using recessed bolts, ten putting on studs to hold a complete top end off something else, like XT Yamaha/XR Honda, etc, all you need to check is the timing chain to camshaft sprocket distance is the same (possibly by using sprocket spacers?), and lines up with the bore.

I might be easier to fit bigger seats, thicker but angled bronze valve guides (to move the valves apart more), then cut the chamber and ports to suit the bigger sizes in the standard head.

I spoke to them again about the crank, but I'm still a bit undecided. I'm not worried about the quality of the crankshaft, as it is a OEM Piaggio crank, just modified to fit the Leader case, but I'm trying not to get madly carried away! The whole deal for me was just to get an aircooled scoot that could cruise at 90-100kph, and to achieve this the easiest and simplest way possible, not to have something to suck the mirrors off a GTS300! I haven't had the cases apart on a scoot before (but have had dozens of inline and Vee 4's apart down to individual bolts, so not worried), but I think changing the crank, although not difficult, may be a lot more involved than just bolting on a big-bore kit and an upgear kit........which is why they are so popular of course! I might even just need to port the head, build and exhaust, set the intake length, then throw rollers at it and the job is done, I just don't have that level of experience with these things.

I do know that for me at least, on an airflow limited motor of any sort, getting more capacity from increasing the stroke can usually give better results than increasing the bore size, in terms of average power across the range. Scoots don't need much power range though, so maybe that isn't an issue for these things?

Oh yeah, and one of these German hotrodders involved with Scooter-Centre has a liquid-cooled, 4V headed 278cc Leader engine running and going.........and putting out 25RWHP on the dyno. 8)

Be careful,the price is too low for a new crankshaft and a new shorter rod.I think it's better to wait until you are sure they have brought it to their scootershop at that price before you send money for a pre-order.
Finally,after the second phone call,is the rod shorter???



It seems easy to take apart the cases:



But i don't understand why piaggio make us to use sophisticated special tools just to change a simple crankshaft oil seal!

I make a quote to myself to show you the huge flow from the normal head of a Kawasaki zx10,inlet side,at the same Superflow flow bench i measured the piaggio cylinder head.It has polished ports from the factory.
ZX10 has four valves per cylinder,bore and stroke of 76 mm × 55 mm and 250cc per cylinder,not very far from ours 190cc .Every cylinder gives about 40 bhp,for a total of 160 bhp at rear wheel.
The flow is about 3 times bigger than Vespa's!

ZX10R 2004


Last edited by dynagrego on Mon, 12 Nov 2012 09:13:55 +0000; edited 2 times

[quote="dynagrego"]Be careful,the price is too low for a new crankshaft and a new shorter rod.I think it's better to wait until you are sure they have brought it to their scootershop at that price before you send money for a pre-order.
Finally,after the second phone call,is the rod shorter???[/size]

Yes, I agree completely, hence the 2nd phone call. If something sounds too good to be true, then it usually isn't true! I was told again the price is definately for a modified crank, that is definately a "drop-in", shorter rod, everything. The modified crank off the GTS300 they also offer however, is 399 Euro, not 139Euro, that price seems more realistic. I thought at first the price was on an exchange basis, I would need to give them a Quasar 250 standard crank in return, but with the language barrier it was difficult to explain what I meant. I wish I could speak German! My friend who is back home there now isn't able to get there to check yet, but I will ask him if he can when he has time to confirm for me the details exactly.

Thanks very much for the case splitting details!

Just for kicks, I thought I'd do a quick comparo on HP/L on another very common and well known aircooled performance motor........the VW Type 1.

Don't laugh, these little things fly when done right! Anyway, they also have a curved inlet tract (goes almost 180*, same as the Leader and most scoots), have very small valve sizes (although the exhausts are bigger as a ratio to the intake than the Leader), and tiny restrictive ports as stock.

Leader 150 has bore/stroke ratio of 1.29, with intake valve/bore ratio of 43%.
1600 VW has bore/stroke of 1.24, valve/bore ratio of 42%.

Malossi Leader 187 has bore/stroke ratio of 1.44, valve/bore ratio of 40% with a bigger 28mm (biggest on seat).
VW 1915 (very common hotrod big bore) bore/stroke of 1.36, valve/bore ratio of 42% with 40mm (biggest on seat).

The point is when you figure out driveline losses for each to get engine output per liter capacity, then calculate the 20% extra revs of the Leader motor (VW 7000rpm - Leader 8400rpm), the Leader motor actually comes out pretty well, both as standard (80HP/L vs 75HP/L VW) and as modified big valve head big bore, etc (96HP/L vs VW 88HP/L).

I reckon Dyna rather than trying to match a 4V liquid-cooled rocket, perhaps it might end up better to capitilise on the Leader features that er built-in to the design, like light weight and excellent mid-range torque.

You'll have to do the whole GPS/Veypor 0-100 tests, that is a very good measure of a broad torque band, and I think it would stack up against the GTS stuff very well.

Two things left for me to do to take some more power without loosing the reliability of my engine:
1.Exhaust,now i use the factory one.I have to match the gorgeus sito plus first but i know that this is not a performance solution.I need more length from my exhaust,everything on Vespa is short.
2.Ignition.I like the malossi for Gts models,i hope that i shall not have any problems with the advance curve.Malossi keeps it secret from us or no one has interested until now.

Of course there is the sccot-shop's stroker crankshaft,maybe later i'll be the guinea pig.

I've been kicking the idea around of using a super trapp can on a properly tuned header. It would not be the most attractive exhaust but it would get the performance correct.

http://www.supertrapp.com/product_sections/cat.asp?CatID=35

To add length to the header, instead of making a 90° off the head toward the right rear of the bike you can angle it to the left and make a loop under the engine.

I have made my order.

who makes that header?

Turbokit!
The red vespa is not mine.




I''ll make a review as soon as i bolt it on.

Something funny.
There is an advantage for us the older guys and big motorcycle owners when we are tuning our scooters:Noone posts snarky comments such as "don't spend your money with that crappy scooter,keep them to buy later a 250cc,etc."

HAHA! I was thinking that as well!
Playing with these little toys is good fun!