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Post by george1966 on Nov 6, 2015 13:09:13 GMT
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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 george1966 on Nov 5, 2015 21:35:42 GMT
You are a star many thanks george
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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 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 george1966 on Nov 4, 2015 10:56:09 GMT
Hi guys thanks for the info ,I have a friend thats suggested we build a 125cc engine to either 1982-1997 (8.6 BHP)standard specs or 1998-2008 (9 BHP)standard en.wikipedia.org/wiki/Vespa_PXI,m trying to find out if the inlet/transfer ports are different/smaller/larger on the crankcases on the 1982-1997....1998-2008 euro 2...2011-2015 euro 3 px,s ,he had what he describes as a bullet proof very smooth running quick and quiet 125e pre cat/euro but we just cant get any info on any changes made to the crankcases over the years?i have contacted several companies that sell engines,crankcases etc but no response? is it a national secret lol george
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Post by george1966 on Nov 3, 2015 23:24:35 GMT
If you compare the hole from the carb to the crankcases on yours and an early P range, this hole, the inlet, is smaller on yours so it's not going to flow so much fuel. Inlet timing is determined by the crank web and the length and positioning of the inlet hole. Between them they control the duration of the the inlet of fuel into the crank case. Or if you like, the inlet timing.
It wouldnt suprise me if the transfers are smaller too, i dont really know tbh.
Changing the inlet timing would involve a full strip down and rebuild
Please remember i have no experience with theese cat'd motors. This is what i read from various forums.
Read more: vespa.proboards.com/thread/5257/px-125-euro-restriction-restricted#ixzz3qTPGkmbehi i have a chap that tunes and builds engines i need to find out all the ......cat restrictions,the exhaust ,carb slide,secondary air,cdi i have all the info on them .............but i cant get any info on the inlet and transfer ports? thanks george
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Post by george1966 on Oct 27, 2015 15:52:12 GMT
Thanks guys george
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Post by george1966 on Oct 27, 2015 11:04:43 GMT
Hi guys the book says 18front 26rear single rider is that what everyone uses? thanks george
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Post by george1966 on Oct 17, 2015 13:16:29 GMT
cheers mate that what i,m gonna do i,m not a young man anymore and with all the plonkers on uk roads nowdays perhaps slower is safer lol george
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Post by george1966 on Oct 17, 2015 12:34:23 GMT
Hi thanks ,i think if your confidant in what your doing and have the experience its fine ,but i think sometimes all the different suggestions and differing opinions are a little overwhelming george
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Post by george1966 on Oct 17, 2015 9:56:47 GMT
Hi thanks for the info, early start this morning met up with the 2 stroke guru lol very interesting the suggested option its more radical than i wanted to do and thats just to return it to pre euro as you say,inlet port, throttle slide cdi jets exhaust port flow ,the one thing i do understand is its your weakest link thing,changing one thing affects another and requires a lot more knowledge than i have lol the list of possible incompatibilities resulting in flat spots,wrong exhaust charge,temperature increases are what lead to seizing premature wear ect my new px runs really sweet she aint fast but pulls smoothly in all gears and running temperature was spot on and as he said the factory's know what there doing ,they have lots of high tech diagnostic tools probes ect to set the bike up for optimum running i,ve got a garage and a box of spanners but i do have a digital tyre pressure gauge lol george
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Post by george1966 on Oct 16, 2015 20:22:56 GMT
cheers mate you are a star george
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Post by george1966 on Oct 16, 2015 18:07:48 GMT
just looked at the engine configuration ,silly me the inlet on the crankcase ,new bike need to get a spare engine to strip to get a better understanding lol george
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Post by george1966 on Oct 16, 2015 17:31:56 GMT
hi is it just something like a nylon reducer sleeve or the casting itself? appreciate the info george
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Post by george1966 on Oct 16, 2015 17:30:10 GMT
Hi just to clarify , is it the carb or engine side that's smaller diameter ?i,m assuming the crankcase side? thanks george
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Post by george1966 on Oct 16, 2015 17:22:25 GMT
hi just trying to get clarity,the barrel and the crankcases are different on a new px euro 3 restricted? george
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Post by george1966 on Oct 16, 2015 16:44:23 GMT
sorry posted as you were posting lol are you saying physically smaller "transfer port and inlet port? thanks george
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Post by george1966 on Oct 16, 2015 16:37:54 GMT
Hi the inlet timing is that the "transfer port or inlet port or both" do you know where you read this? and if the cdi has a pre set advance curve based on standard mix ratio ,how could you ever tune,change exhaust upjet ect it would never run right ,and could run really hot george
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Post by george1966 on Oct 16, 2015 14:41:55 GMT
All my carb problems have been contaminated fuel "crap in the tank" clean fuel filters if it doesn't have one put one in george
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Post by george1966 on Oct 16, 2015 14:33:38 GMT
Hi i believe a vespa px euro 3 has extra air pockets in the throttle slide which makes the mix lean for the cat exhaust i assume this would need to be factored in if you were tuning ,i,m taking the bike to an aprilia 2 stroke race bike tuner ,it appears he,s a bit of a 2stroke guru ,i,m trying to find out if the cdi has a pre programmed advance curve based on mix ratio or is just a simple rpm retard
george
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Post by george1966 on Oct 16, 2015 10:52:23 GMT
sorry should have posted my question here
my px 125 is euro 3 restriction, i know about the exhaust cat,secondary air box,throttle slide and the cdi rev limiter but are there any other parts or devices restricted .I read on here something about the inlet timing?but it wasn't clear or at least not clear to me lol thanks for the forum and your help george
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Post by george1966 on Oct 16, 2015 10:49:09 GMT
Hi and hello i have a px 125 2015 that i really like ,i,m new to scooters but not motorcycles ,i been reading lots of the posts very informative my px 125 is euro 3 restriction, i know about the exhaust cat,secondary air box,throttle slide and the cdi rev limiter but are there any other parts or devices restricted .I read on here something about the inlet timing?but it wasn't clear or at least not clear to me lol thanks for the forum and your help george
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