Modern Vespa

vespa px125 evolution 1982-1997 (8.6 BHP)standard specs or 1998-2008 (9 BHP)standard px125 euro 3 (6.5bhp)

en.wikipedia.org/wiki/Vespa_PX

If the standard pre cat vespa px125e /px 125 euro 2 ,used a 20/20 carb 96 main jet and produced 8.5-9 bhp
and the 2015 px has 20/20 carb 96 main jet and produces 6.5bhp the leaning of the engine is derived from ,the throttle slide ,smaller inlet port/transfer,exhaust cat,secondary air box.

if putting a sip road 2 exhaust on and re jetting and drilling the air filter produces a suggested increase of 1.8 bhp on a px125 2015 euro 3

then a standard px125e 1982-1997 or px125 euro 2 1998-2008 engine would produce the same bhp as the sip road 2 ,with drilled air filter and jet mod on a px125 euro 3 2015 ?

so building a pre cat engine to 1982-1997 (8.6 BHP)standard specs or 1998-2008 (9 BHP) standard ,would keep the standard quieter exhaust whist retaining the smooth power delivery?

george

Probably.

You need to find a hobby. Do you have documentation that the inlet port/transfer is smaller?

The cat exhaust and air box are basically a single system.

The purpose of the cat exhaust system is to oxidize carbon monoxide and unburnt hydrocarbons (both considered pollutants) in the exhaust gas to carbon dioxide and water. The cat exhaust reduces emissions independent of the mixture, and <u>it's purpose is not to "lean" the air/fuel mixture</u>. Since the mixture in the PX engine is already on the lean side in the Euro 3 version, there is insufficient oxygen in the exhaust gas for the catalyst to oxidize the carbon monoxide and unburnt hydro carbons. Thus the air box is there to meter air (oxygen) to the catalyst.

However, the cat exhaust does restrict the exhaust side of engine aspiration, and that is why a non-cat pipe of any variety will improve performance, since on a 2T, exhaust restrictions ultimately cause intake restriction.

Not suggesting alternatives, but simply explaining how the cat exhaust fits into the equation. One could very well design an after market cat exhaust that "breathes" better, keeps emissions down and provides a bit more power than what is on the stock PX Euro 3. Question would be if it would make economic sense.

LOL retired ,this is it
i have tried /emailed everybody i thought could possibly know !!!!!!!................how it possible that every little detail of theses bikes is available ,but a casting or machining difference of the crankcase no one knows about ? i have had several people say they think so but are not sure?
contacted supposed experts yes and not sure?

On the advice of a few forum members i have abandoned the buy a secondhand fu*ked up engine of ebay LOL so build an engine from new parts based on the info i can get

I have a great friend that's going to help as a sort of joint project (do the heavy work)and he suggested we just build a derestricted 125cc engine we can just drop in and everything we learn ,can then be applied to the existing engine

wanting a completely standard "as it was designed and intended bike" seems to be frowned upon .....................my reasons for buying a 125cc scooter were probably very different from other peoples , i have a full licence i can buy and ride anything ,so a simple functional little 2 stroke probably appeals to me on a different level.

In all honesty shes fast enough for the little pootling around the county lanes of norfolk i do ,avoiding ,tractors deer and idiots lol but my lovely vespa px has been altered not to enhance performance or reliability but because of some bloody bureaucrat in brussels ,that burdens me with emissions legislation that most of the world casually ignores lol

I know its crass but it just erks me ..................lol if she did 150mph
and i only ever rode her at 60mph ,i would still want to remover her shackles
george

george

I really wonder if the cases and crankshaft have been changed. I would lean more towards the addition of the variable timing, stator and carb slide change, along with the existing cat exhaust system from the previous iteration.

In fact, I was quite surprised that Piaggio went to the trouble to do a "one last stand" 2T at all, but it has gotten then several thousand units in sales to shifty purists.

The only way to determine of there has been a case/crankshaft change would be a teardown. I don't know who the "experts" are that you refer to, but to me, the only real experts work in Piaggio Engineering. Short of a teardown and side by side measurement, there is no way anyone in the field can make an authoritative statement. Even part numbers can be misleading, as Piaggio has been known to change a part number without a change in the part itself.

To be honest, it's a rare bird that knows anything about emissions control, especially in the 2T community. It IS NOT simply a matter of leaning the mixture. Yes, a leaner mixture can help, but it is not the end all, be all. The catalyzed exhaust, BTW, results in smaller jets because of the impact on aspiration more than anything else. You just can't move as much air/fuel mixture into the combustion chamber with the cat exhaust.

If your goal is to achieve a pre-emissions control engine, then either start from scratch with a rebuilt older engine, or replace the stator, ignition system and exhaust with pre-emissions era parts and configure the carb to match. Those are the only changes that anyone has really identified.

I'm skeptical about the cases and crank as well. Changing these things involves reengineering, and then paying for new casting/tooling and a new line of parts to be manufactured... these companies are about profit. They are going to try swapping parts around and such before any major design/manufacturing changes (e.g. the 20/20 carb on P200e in USA in 80s - left everything else alone and just plopped a funky gasket and an already designed/being produced smaller carb on and see if that can bring it into compliance)

I just had a brain storm.

Take it to a Volkswagen dealer. They have a proven track record in defeating emission controls.


Couldn't restive.

lol, their Lo-Emissions-R-Us division will hook you up

Brilliant!

if you like the stock thing - but want more power. Then why dont you build 200cc motor from scratch while you are at it. Youll have 12hp instead of 9hp or what ever.

So, you don't want or need to go faster. You just want to casually pollute because somebody said you can't? These threads are my favorite.

Hi its a good idea i haven't totally abandoned the 200 lol but simon had an earlier vespa 125 and having now ridden a newer tuned 125px 9bhp is probably as much power as i'm comfortable with on the 10 inch wheels lol how right you are ,obviously you don't ride a two stroke or have ever fitted a kit or expansion chamber or bigger jets etc Such a man would probably have retro fitted a cat exhaust to cut his carbon footprint ? surely such an enlightened intellect would actually have an answer to my question? lol
george

I really suggest you ride someone's 200.

Sounds like a reasonable conclusion. Go for it! Wait... remind me again, just what are you trying to do? IIRC, you don't want to void your warranty & won't be changing anything until that's not an issue, so when does that expire? george george george,
settle down, he made a good point and this was NOT an 'lol' response, now was it?

You say some stuff, whatever you want, and ppl respond.

lol, over & out

Hi its going to be a joint fun build and it will be a spare test engine as the new ones under warranty ,as its only three months old ,

all the horror stories and advice i,ve received concerning fleabay engines .......................thanks guys ......we decided new cases and all new parts ,it will not only be fun but give me practical experience of my own px125 engine and we figured that any alterations we needed to make could then be applied when the warranty runs out to the existing engine (inlet/transfer ports)if they have been altered,also it will be direct plug and play swop as a comparison and to test

the general consensus is the euro 2 and 3 have strangled the px i kinda like the idea of returning to................... as intended the section not so modern is probably for and about the least environmentally friendly motorcycles available,if one were truly concerned for the impact 2 strokes have on the environment you wouldn't own one.... if this had been posted by a passing cyclists i would have considered it a valid criticism

I love the banter and jest of the forum but its usually precipitated with at least an opinion of the proposed question or something humorous, to be fair to the poster my irritation with the bureaucrats in brussels goes a lot deeper, its the hypocrisy and distortion of the truth ,by creating a carbon tariff manufacturing is not economically viable,so its outsourced to countries not regulated ,no filtering, fossil fuels regs

so your toaster actually creates a much bigger carbon footprint made in china than in europe/usa............................but we cant measure that

i apologize if i offended and i should have worded it better

I want a standard de dibbled px, i don't really need or want to go faster ,but if i did want too "i could"
george

watch the political stuff, please. A definite guidelines no-no.

A non euro 2 or 3 px125 is still a slug. Why waste your time building a stock p125 - it's baffling. It will cost same to build a 200. Every time I've ridden a p125 I laugh because it's nearly useless. 50 mph isn't cutting it for me. It's not so much as really going faster than knowing you have the extra power on tap to get you out of a bad situation or when needed. All I can say is just don't forget the cotter pin !

Hi sorry thats why my post was a little ambiguous i didn't really explain just said " some bloody bureaucrat in brussels"
duly noted
george

sorry posted mid post shouldn't laugh but

what do ya think ? just chatting with spogg maybe your 200 build would at least be predictable don't imagine the 200 crankcases have changed much
george

It was a serious question, I've never had a new Vespa. Is the warranty there for miles or months or some combination? If miles, when would you expect to hit the end given your riding habits so far?

It might help ppl answer some of your questions and offer better advice if your approximate time horizon is known.

Hi mate sorry should have said ,its two year warranty parts labour and breakdown, i did talk to the shop but everything suggested on the forum invalidates the warranty lol

so to enjoy the bike and tinker ,building a px125 spare pre cat spec engine ,seemed a fun and interesting project ,and as its so easy to drop the engine we can evaluate the changes we make, direct comparison and in building it will learn as we build

I want to see first what a pre cat engine runs and feels like, as there's so much info on how its been "muted"but it also leaves the door open for future tuning ,whist always having a running bike

george

This does give us 1 year and 9 months to consider these changes.

i,m afraid that may be a little optimistic now ,scolded and shamed for my casual and cavalier environmental attitude ,i will need help and advice on a way to reduce the increased hydrocarbon emissions................possibly only ride ,every other day? how have others coped with this added burden ,i realise this is a dilemma all of us face ,just owning a 2stroke ........................just when i thought i had it sorted !!! back to the drawing board

george

Got it, thankyou. So.. given your situation and new found desire, you could just ride it responsibly for a year and a half(every day if you like) and see if you still want to change back to a primitive agricultural motor with all the additional power unleashed. A year & a half of speculating & investigation should be adequate for you to reach a conclusion you'll be happy with and you will learn much, as you said. Three months preparation to implement your plan will be enough I think. Hope this helps.

Best of luck and happy guilt free riding on Piaggio's warranty meantime.

Hi mate that's an excellent assessment, by the end of the warrantee i should have a spare de restricted engine ,in either standard or tuned form thats been in and out of the bike probably numerous times lol and everything we've learned in the spare engine build ,we can then apply the modifications to the existing engine when the warranty runs out
we now have say 2/3 months to build ,bench test ,then drop it in spring time

A nut and bolt build is a great way to learn and i,ve been assured lol dropping the engine is so easy i wont be without a working bike ,and i'll keep him to that promise or i,ll be riding his ducati lol

I know i,ve asked crazy a amount of questions and irritated many members with my need for clarity ,but the knowledge and advice i have received has probably saved me many hours of hassle and £100s on crap secondhand engines or basketcases ,

its been a different learning curve for me ,out of my comfort zone the one great advantage of a px over my other vintage builds is its a current model and parts are readily available spoilt for choice ,

i spent months trying to locate a genuine yamaha worm gear and pad chatter springs are no longer made,you had to buy what you can get then repair weld tap !!!!!!!!!!!!!!!we were pricing up last night til late lol sip,beedspeed etc websites you can buy everything, like an airfix kit and a fraction of xs parts cost
don't worry when the parts arrive i won't bore you all with assembly lol
cheers
george

"...in and out of the bike probably numerous times" ???

It's not hard, but not so easy that I'd want to use my only running scooter as a test stand for the motor you want to build. Things can and do go wrong sometimes and sometimes things break. Warranty won't help then & maybe would be canceled. You do the have time, just whip together a test stand from an old car wheel and some scrap steel. Pretty simple, just 3 mounting points and you'll avoid the risk of messing up your new scoot and possibly voiding your warranty.

Maybe when it's DONE swap it in for road testing if you want to take the risk just once and by then you'll know a lot more. Does your work mate have & worked on Vespas or is he speculating?

Looking forward to your assembling and I don't expect it to be boring. Frustrating, perhaps. What else is new?

love the very cool way of engine mounting that sums up my perception of the resourceful functional but also stylish vespa ethos

my mate had an early px but has built some crazy complex bikes,we can bench test and hopefully have access to a dyno ,as you say get it running right and see how it feels in the bike,we could just do a simple buy it and disassemble, its a hobby for me so its all fun and i,ve been given permission to use the conservatory if its cleanish (the conservatory is well heated the workshops bloody freezing lol)

http://www.sip-scootershop.com/en/products/engine+lml+for+vespa+p150x_78005500 i have bought a decent video camera so perhaps disassemble record and play in reverse lol
life is strange spent half my life with running bikes and bikes in bits moaning and groaning about not being able to ride the one i'm restoring lol ........................so i bought a brand new vespa that works perfectly requires nothing ,for the little hour runs around the countryside i do ..........and i'm compelled to.....................you understand lol


george