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Post by george1966 on Nov 4, 2015 12:52:13 GMT
Hi guys a question
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
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Post by henri on Nov 5, 2015 8:44:38 GMT
your figures seem to be from wikepedia , an we all know how reliable that is .an are probably just quoted from piaggio figures ,an we all know vehicle manufacturers never fudge the figures or rig tests dont we .build it to a decent blueprinted spec ,like the 1's piaggio tests for figures, run a sip road2 ,but not a chrome 1 if noise is a concern ,drill filter n jet accordingly an you wont be disapointed . H
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Post by george1966 on Nov 5, 2015 16:45:03 GMT
Hi the general consensus is each additional euro 2 then euro 3 has "stifled"the px thats using the vespa data i have a friend that had an early 125p and he suggested we joint build a new 125 pre cat spec engine as my arthritis limits what i can do ,but as i built a 400/4 with him its pay back time lol my px is in warranty ,so we can build the engine from new parts, take our time so i always have a running bike ,but we are a little stumped as we cannot find any factual info on the possible differences in crankcases inlet/transfer ports so it's had to know what to buy
if i was a bit younger i would have stripped the bike and measured but i'm really enjoying my little px rides and its the first time in donkey's years i,ve had a bike with "no to do list" lol
george
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Post by henri on Nov 6, 2015 8:36:36 GMT
as on other post gaz's info tells you exact dimensions ,if you pull up base gaskets for vespas on e bay theres listings with 3 n 5 port gaskets in same picture .you can see the similar shapes n size differences there .for confirmation there cheapish 2-3 quid ,order 1 of each an compare .as doing a build ,get the best barrel for your planned usage ,a 5 port one an match the transfers to cases so theres a even/smooth channel for gas flow .dump the rest of the restrictive kit an you'll have a better engine than the earlier un-restricted px's . H
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Post by george1966 on Nov 6, 2015 9:43:27 GMT
Hi mate i don't want to put on a kit/new barrel,i've been trying to get all the information on px evolution changes, from "un-restricted to euro2 euro 3 px's and learn and understand how things like the inlet size and timing impacts on the exhaust charge, temperatures,velocity and pressure,my px is under warranty and as my friend had an early px we can build a new px spare engine that we can just drop in and experiment with, the build list www.pmtuning.co.uk/engine-cases-vespa-px-125cc-150cca 20.20d carb with the non cutout slide 96 main jet ,standard exhaust etc all other parts seem interchangeable and easy to buy ,whats causing the difficulty is the changes in the crankcases,the more we read up on 2stroke design getting "inlet timing exhaust charge flow,pressure blowback fuel mix " all working together is not as easy as we thought lol we decided that vespa engineers did all the work and knew there stuff so just replicate a pre cat engine but because of the changes in parts,its probably going to be better idea to build a px200e engine as its basically unchanged and we can just assemble without too much head scratching lol thanks george |
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Post by henri on Nov 6, 2015 11:44:55 GMT
it seems to me your over-thinking the job , an trying to re-invent the wheel , unless high-end tuning all exhaust gas behaviours decided already by exhaust maker .an inlet timing by crank n cases already set .same with initial compression/blowback . the piaggio engineers did know there stuff an designed a low stressed/hardy engine that can run on crap fuel n abuse n survive .
if going to buy new cases i'd advise lml reed valve 5 port cases an barrel , the developement on the old px type without euro strangulation , as the cost of px200 cases will be a lot more than 125/150's an you'll probably only find 2nd hand .a p125/150 lump can be had for 3-400 , a p200 more like 700 . an building from bare cases is expensive by the time youve added up all the little stuff on top of major components .H
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Post by george1966 on Nov 6, 2015 13:09:13 GMT
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Post by henri on Nov 6, 2015 14:21:01 GMT
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Post by george1966 on Nov 6, 2015 16:21:54 GMT
hi mate i,m happy with work now my friend can help ,but have been advised to avoid the ebay secondhand list as can end up costing more to repair than a new one and most have been kitted or fiddled with lol george |
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Post by george1966 on Nov 6, 2015 16:39:43 GMT
are you wanting a project engine to build or just a standard bolt-in pre euro engine? if your fitting this within your 2 year warranty wouldn't it be easier to just fit a non-cat exhaust instead of a full engine? standard ones ive seen go for £25-£30 on ebay or better still a sip road your 7000rpm restricted cdi shouldn't bother you unless you want a tuned engine pulling 65-70mph,if your happy upto 60mph its fine Hi I want a project engine pre euro because i want a smooth running quiet engine de restricted engine , fitting a standard exhaust and removing cat ,to the existing engine does not take the altered inlet/transfers into consideration ,the exhausts you can buy were calibrated for size inlet size /timing of earlier pre cat engines ..........don't know the physics/mechanics? its gas lol..... of it ...but rough running seems to be the outcome ,i dont know if it changes the charge, i have no idea,but a precat px runs sweet like my new one just more powerful en.wikipedia.org/wiki/File:Arbeitsweise_Zweitakt.gifnot sure i,m making sense but someone clever will explain why lol george |
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Post by george1966 on Nov 6, 2015 16:51:16 GMT
I should have said i had a very helpful message ,almost a warning .......every thing you change could impact on the next change,ie something as simple as replacing the cut out throttle slide is a critical part and is usually ignored
if i have a project engine smooth running non euro 1 we can test it in the bike and at the end of the warrantee
use the non euro 1 as a template for the existing one if its practical
george
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Post by george1966 on Nov 6, 2015 21:26:29 GMT
hi either if we buy we will then strip
george
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Post by george1966 on Nov 6, 2015 23:00:39 GMT
Hi i think it depends on what you want from a bike ,my mri scan scuppered my plans if my back had been up to it i would have bought a ducati scrambler,so the px,s qualities for me are the agricultural simple pretty functional ,speed wasn't a consideration,it inhabits a different space ,i,ve had rocket ships ,off road monsters and totally functional and the best bike "for its intended purpose" i ever owned was a c90 honda ,the complete motorcycle bulletproof simplicity itself cheap to run it ticks every box,it was designed to fill ,
my ktm 640 supermoto tuned with not meant for road use tyres lol was the most headbanging fun ,but the castering effect gives awesome direction changes but its limited to 110/115 mph but it gets there fast......... and power wheelies everywhere,i have enjoyed all my bikes but for very different reasons,buying or building a spare pre cat px engine is a big part of the fun for me,my mates take the p*sh a little lol about my px 2stroke but only cos its a scooter,but like the c90 R1,kettle kwack9,400/4 t120 b51,mv ect it is a motorcycling icon,it don't need bells or whistles,funny twist gears 2stroke 10"wheels its a vespa
george
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Post by george1966 on Nov 6, 2015 23:19:56 GMT
sorry sounds a little presumptuous,bikes to me are are like women ,when i think of my youth and former girlfriends they have had a unique quality,prettier,taller,fatter thinner but the whole package makes them special ,sort of horses for courses
and your wondering why i'm divorced lol
george
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Post by george1966 on Nov 7, 2015 14:47:42 GMT
so you need a new pre euro piaggio rotary valve engine?,,cant see you fitting a LML reedvalve or would you? lol what you going to do with it? just strip and rebuild it? why? I,m a bit of a tinkerer and have built several bikes nut and bolt up over the years,strip and rebuild is a great way of learning any of idiosyncrasies of the design lots of fun and saves you money ,a simple clutch rebuild in an xs 650 £260 parts £40 ,swing arm bushes £75 parts £9 and as its yours so you do it properly..............hopefully lol my xs650 was relatively quiet lol smooth running reliable the chap that bought it was amazed, as he had tried several, its not a talent, is dull meticulous research and attention to detail,i don't care about paint jobs stickers lights loud exhausts etc lubrication lubrication lubrication lol one very important lesson i have learnt to my cost ..........lol.......is companies like vespa yamaha suzuki etc have huge budgets great engineers designers diagnostic tools to get a bike setup and running correctly and some of there bikes unfortunately fall into the hands of some people that think you can just simply bolt on a couple of bits ............ the xs forum was awash with aftermarket bolt on c**kups lol and after a lot of head scratching and kicking my guts out, i returned the bike to stock and it worked brilliantly with bulletproof reliability george |
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Post by henri on Nov 7, 2015 17:19:39 GMT
erm , you wouldnt still have an xs650 bits around would you , ive got to re-do a mates US spec 1 to be legal n pretty over here . an am always on the look out for a un-molested engine , as ive been offered a "uncle chufty" frame an would love a xs650 lump for it . name dropping here , but its the man himselfs given it to me .
agree with ya logic above ,an do all my own work myself , but its more of a enjoying learning new skills an gathering knowledge thing for me .but with piaggio your research is going to run into a problem . they run 1 model into the next one ,are parts-bin specialists ,an dont keep public records of when changes are introduced .plus change stuff for every market an then import to another market to cover shortfalls .all that plus the general mis-information/rumour/gobsh*tes an personal theorys you'll get makes it a minefield . oh ,an if ya think xs owners were bad ,scooterists are the worst for "stuck a big carb ,exhaust off a mack truck,an a bottle of vodka in tank as octane booster,to go faster coz a "guy/tuner in the pub" said i'd get 90 out of it up everest" , an now it wont start an makes a funny crunchy noise .must be the lawnmower plug i borrowed coz the one from car stopped working. etc etc . you got to love em , scoots that is , scooterists drive me nuts . H
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Post by george1966 on Nov 7, 2015 19:01:10 GMT
Sorry,have a few tools? i had lots of spares new and old he had to collect with a van lol the px was to be a ride only with a warranty no wrenching,but its hard to shake lol
scooterists are the worst for "stuck a big carb ,exhaust off a mack truck,an a bottle of vodka in tank as octane booster,to go faster coz a "guy/tuner in the pub" said i'd get 90 out of it up everest" , an now it wont start an makes a funny crunchy noise .must be the lawnmower plug i borrowed coz the one from car stopped working. etc etc . you got to love em , scoots that is , scooterists drive me nuts . H
very good .............LOL .............that sums up exactly why i research everything there is a great old expression
Before you do anything "wait for the guinea pigs to f**k up"
george
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