Modern Vespa

We did figure out the problem. The diaphragm was not seating properly. A wee bit of Yamabond tacked the edges down enough to install it properly. All the difference in the world.
Just got back from testing different rollers in the variator. BIG improvement!
Still seeking original top speed of 60-62mph. Consistently doing 57 now.
Much happier now that most of performance goals have been met. 8)

Νow install a polini upgear kit as i describe at page 1 of this thread.

Driller - we're considering a Libery 200 barrel and piston for our Fly 150 downstream, and enjoying both this thread and yours. Interesting you aren't seeing more top speed, but the upgear should take care of that. Other than that, what do you think? How's the torque? Where are you feeling it - low, mid, high revs? Any downsides to the kit or issues with installation?

Thanks, keep us posted.

Mike,
Just a couple of more tests with different roller/slider weights and possibly clutch springs and we will be ready to do a summary of mods and weigh the merits of our project. After a lot of trial and error, the bike is now running strongly and has almost met the original performance goals. The acceleration times on our measured course are now comparable to my GT200. Lack of higher top speed doesn't bother me too much since the GT has the legs to deliver that.
We are trying to arrange a "shoot out" between the "BlowFly" and a "Malossi Fly" at the drag strip. Might be interesting.

Leader air cooled engine is just a torque machine.You ''ll never touch the speed of light with it.
Valve size is it's limit.
Compare valves between leader and ancient kawasaki Z2OO A1 1978(Bore x Stroke 66 x 58 mm).

VALVE DIAMETERS
LEADER IN=27mm
KAWA IN=37mm

LEADER EX=21mm
KAWA EX=31mm

Wish I could turn you loose on my bv500 engine.

Mike, (Driller), just pointed me to this thread. Wish I would have read it a couple months ago. Tremendous amount of brain power here. Like a good book, once I started reading it I couldn't stop. Our efforts are no where near as extensive as yours and it's clear to me that you have much better resources available to you than I have.
What was the final outcome with the stroker crank? I was wondering if that requires a cylinder spacer or shortened rod. If spacer, does that cause clearance problems with the frame and head? I really doubt that the rod could be shortened 5.7 MM without the piston pin boss hitting the crank. I've done a couple home made strokers but had to limit stroke increase to 4.4MM to avoid this. Maybe a combo of spacer plate and rod shortening?
Also, what is the transmission ratio stock and upgear? After looking at Drillers bike it looks like a 130/70 rear tire would go right on. Near as I can figure that would give us about a 3% taller gear.

no stroker crank (yet).The size of the valves are enough for 125 cc,not for 250.I suppose that i''ll have no power gains but a slower revving motor.

oopsclunkthud member is the gearing master.All about leader gearing tables at just one thread.
LX190 Testa Rossa

130 rear is heavy,an acceleration killer.

Hello to All

First and foremost, i would like to congratulate all the posters to this thread, Dyno,OppsClunk,Modnrod and others - this has been one of the most informative and educational threads i have read in concerning the leader 125 engine -

I have been lurking here reading my way through all the postings, many times to make sure i am up to speed (sic) with what i would like to do with my new purchase

I am a paraplegic, and have recently bought a Nippi 125 trike to get out and about it -
http://www.usatechguide.org/blog/nippi-wheelchair-accessible-gas-powered-scooter/

This trike is built around the Piaggio 125 Fly scoot, but has an additional frame built onto the scoot frame, so a little more weight to the whole thing

As mentioned by others, this rig goes well, but just lacks that extra grunt to cruise along at about 60mph, sits at 45mph comfortably, but feel like i am wringing its neck to get anything above 50mph
bit frustrating for an old biker like me

So after reading my way through the posts, this is what i have decided to do with the wee beastie.

1 x 200cc Liberty Cylinder kit, with the additional gaskets

1 x Polini Gearup kit

1 x Malossi Multivar Variator kit
this with white contra spring & yellow clutch springs, along with 12.5 gram rollers (Malossi Kev Belt)

1 x Thai Keihin carb,javascript:emoticon('')

aahh and also that ignition box that Dymo mentioned. (apologies for the technical term)

Would you guys give my list the once over and point out any obvious errors or omissions i might have made, i would be very grateful.

This is going to be a summer project for my son and I, maybe even buy a donor engine to work on.

Your thoughts would be appreciated

All the best
Alan (Pringle)

You don't need malossi cdi because factory camshaft,valves and porting don't let your engine to rev up enough.

It's better to buy a good exhaust but be sure it clears your swingarm enough.

Thanks very much for that Dyna - forgot to mention the exhaust.

with all these mods taking place, in your opinion, would the crankshaft be strong enough for the additional load?

just that it has been mentioned in conversation that i should change that out also,

many thanks
Alan

You just fix a factory cylinder-piston like piaggio does,you don't change compression or spark advance that can affect crankshaft's mileage.
Two years after,mine sounds okay.

The crank is basically the same design as the GT200 and even the GTS300, so I'd not worry about it taking the load.

Thanks for that guys,
coming from yourselves, that puts my mind at ease

now to shop around and see what this lots going to cost lol

cheers
ALan

Nice tread ! *Thumbs up*

Now I'm curious what could be done to the 3v motor. I'm a little disappointed in midrange and top end power. Wondering if the smaller intake valves actually flow less at higher rpm's.

Answering to some questions about Κeihin Pe 28 main jetting:
I always follow this method.

ROLL-OFF(from the Mikuni site):
The Roll-Off technique is the quickest and is almost as accurate as the Roll-On method. First, one gets the engine warm on the way to a safe roadway. If there is room, use fourth gear as this allows more time to assess the result.

Now, get the engine rpm high enough that it is on the cam and in its power band. This may need to be as high as 4000 rpm with some cam choices. Apply full throttle. Let the engine accelerate for a couple of seconds until it has settled in and is pulling hard. Quickly roll the throttle off to about the 7/8ths position. When you do this, the mixture richens slightly for a second or so.
If the engine gains power as you roll the throttle off, then the main jet is too small and you need to fit a larger one.
If the engine staggers slightly or has a hard hesitation, then the main jet is too large and you need to fit a smaller one.

Hi Again

just a quick update on my attempted upgrade on my lil 125 nippi - all parts have now been ordered and arrived safely, even the carb from Thailand.

i have bought the following - costing in GBP

Piaggio 200cc Cylinder kit - 151.

Pro Street Clutch bell - 47.

Malossi Delta adjustable Clutch - 94.

Polini 'Gear Up' kit (shaft and gears) - 74.

Keinhin PE 28 Carb, with caskets and jets - 61
plus extras.

Polini Sport Variator kit (Speed control Hi-speed) - 114
complete with two sets of rollers,
contrast spring and sliders.

Malossi Kevlar belt - 31.

Sports Exhaust from PM Tuning - S/S - 247
exspensive but heck, looks cool LOL.

Gasket set, Spark plug, Oil Filter, special tools oils and 'stuff' - 70.

so, now we wait on time being a friend to my son, so we can get this trike into the adapted workshop (10ft cargo container) and do the bizz - looking forward to both the build and the perfomance difference - for the better i hope, bit pointless otherwise aint it.

I will be keeping a photo blog of the work, with maybe a gopro vid or two thrown, will keep you updated on that.

Wish me luck folks, and again, thanks for all the info and tips on this thread, given me the confidence to go ahead with this.

regards
Pringle (Alan)

Υesterday i changed the thai PE28 pilot jet from #35 to #40 according to my country temperatures.
It starts,idles and runs like a factory carb now.

This carb from Thailand doesn't use the same type of pilot jet with the japanese PE28.
It uses the fcr type as you can see at the picture.
http://www.ebay.com/itm/KEIHIN-spec-Stage-6-KN-OKO-KOSO-PWK-PE-PJ-FCR-CR-Carburetor-Slow-Pilot-Jet-40-/181204804177?pt=Other_Vehicle_Parts&hash=item2a30a5e251&vxp=mtr

Hi i have also et 4, what for size carburetor have you on this?

Hi i have also et 4, what for size carburetor have you on this?

Any theory on why this one didn't work as well as the Thai copy? Essentially the same carb.

Lots of tuning info and success with the Japan PE with the miniMoto crowd. Your final set up looks close to what they're running on big bore Hondas.

Looks like vendors are selling 2T and 4T versions with different emulsion tubes and slides out of the box. Possible yours was a 2T carb?

Any opinion on the Dellorto VHST? After much internet research I'm down to a choice between VHST and Keihin PE. My criteria are I want to be able to retain stock airbox and pet carrier. I think either of these will work with a 90 deg. cable bend and minimal adaptation.

My new genuine PE28 from japan uses JFN jet needle like most 4stroke mini motos and xr200 of the forums,so i suppose it's made for 4stroke models.I think it's failed because of wrong for my bike main AIR(not fuel) jets and passings.These air jets are prefited and not adjustable like those from fcr carbs.
I don't see any good reason to keep trying on setting them or trying Del'ortos.

These Thai PE 28carbs with the yellow big idle screw(i am not their seller-i am Greek) are cheap and working perfect out of the box.

The early ET4 came with a dellorto carb that will drop right in, but I think it's only a 26mm carb. The OEM throttle cable that goes with that carb should work on the PE as well.

Nice find.

But it's only 22mm, PHVD. And from research spigot at motor side is 29mm vs 34mm for Factory Keihin and aftermarket 28s. Not exactly a performance setup.

Too bad because a bolt on solution complete with electric choke would be sweet. Looks like cable and cable bend should work though.

Warning:
If you remove the decompression device for faster revving and use a high compression Malossi overbore kit,be sure that your battery and starter relay are in perfect condition to give enough torque to crank the engine.
Starter relay(80amp) is easy to change and very cheap and it's better to change it with a new one.

And you are not going to be able to use your kickstarter any more.

Brilliant and very interesting.I shall be fitting a Liberty bore kit as soon as possible.I love my old ET4 but is,alas,a bit wheezy.

what do you guys recommended for primary gearing to be used if i were to track my bike? currently using polini 17/44 primary and stock secondary for my LX. On 190 malossi block.

you can find some useful tables here:
LX190 Testa Rossa

Dangggg, 2014 vietnam LX150 cdi unit is different from your bike hence i cant use my newly bought Malossi CDI part no M5512341. Is there any adapter available so i can use the malossi cdi?

I think that your LX150 is a 3Valve injection NO leader engine.

nope..mine is lx150 2v carb

is still sell exhaust ?

If you go with the Keihin Pe 28 from Thailand,don't forget to order it with the remote choke bowden cable kit for easy operation without opening the engine cover.

Tune 125 et4

I solved the problem with the tension of the spring of the throttle stop screw: after some hours of driving the vibrations of the engine and the low tension of that spring make the throttle stop screw loose and cause low engine idle speed or frequent stalling.
I increased the length of the spring by pulling the ends with two pliers and now the throttle stop screw stays at the point i set it.

It's been a while since you posted, thought maybe this would be the blow-up report. Good to hear it's running fine.

The only thing i blew up twice was the 80amp starter relay.
That happened because of malossi's high compression in according of removing the decompression mechanism.
I changed that relay with a stronger at 120 amp and i had to modify the contacts at the ends of the relay's wires to make it fit.

Malossi Multivar variator failure.
After 21.000 kilometers of use,the central axle(Sliding BUSHING) seems to be seized to the pulleys's housing as you see at the photo so even after beating on it with a hammer I can not get it to release. I had to give up and go back to the factory variator.I know that i can heat up it or press it down but i don't trust it any more,i think i lost my money.


Axle was stuck on the pulley and can't move as it supossed to do.


Right side of the group axle-pulley


close view



Instructions from Malossi store for VARIATOR MULTIVAR 2000 with Article code 5111397 (piaggio leader engine).
http://storage.malossistore.com/files/montaggio/7311323.pdf
"TECHNICAL FEATURES:
- HALF-PULLEY made of aluminium alloy with silicon content, machined on very high-precision CNC machines and diamond-finished, with recalculated profiling of the roller sliding guides.
- Sliding BUSHING made of self-lubricating sintered steel"



This is how the rollers look like after 8.000 kilometers.
They easy loose their shape,i have already replace them two times.Not so good quality i think.

Good to know