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Post by pxguru on Apr 11, 2015 15:42:09 GMT
I have brought a totally standard year 2000 PX200. This is going to be my alternative daily ride. My Polossi is really great and proving to be highly reliable but revs high when crusing and drinks fuel like its got a hole in the tank. The new scooter is generally ok. Slightly hard life but not long had a full respray. A very decent job an looks smart. All factory standard engine wise. Jumps in 1st, 2nd....and 3rd (sometimes). Front shock is dead. Doesn't always start on first kick but ok on starter motor. Like a normal PX200 it has a thumping tickover and feels really strong to ride, pulls hard uphill but actually goes very average speedwise. About 65mph on the flat. Got 70mph on the clock downhill, probably little over 60mph on GPS in the real world but would do it all day long What I intend for this scooter is going to take some time to do. My job and homelife are far too busy to keep at it. Planning on being done by Christmas. The plan is to fix all the general issues and make it into a reliable tourer based on a standard iron barrel. Engine will have all new seals, all bearings, 3 new gear cogs, hard cruciform, primary drive springs, full clutch, SIP Road II, standard PX200 barrel rebore to Grand Sport thin ring piston (from my shelf and already ported) and SI26/26 carb with autolube working. Its going to have the same bottom end power and torque feel of a standard PX200 but will rev to over 7000 in 4th, when required I'll be buying all the parts at the end of the month. Going to split it twice though. Will do a quick split to fix the gearbox, change clutch and put on the tuned barrel. Will split it again at the end of Summer to do the primary, change the seals and bearings to do a proper job. I'll use this thread to post the highlights as I get things done.
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Post by sime66 on Apr 11, 2015 15:50:01 GMT
Splendid! Very much looking forward to seeing it done properly
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Post by vespasco on Apr 11, 2015 19:44:14 GMT
Sounds like a good 'un! I like the just over 7000rpm 'limit' as it still gives you all the torque where and when you need it for a daily rider, id imagine max torque around 6000rpm +/- a little? On the subject of exhausts, (again) have you concided the BigBox?! These loads more power to be had from one of them over the sip road and they work on a stock motor. (And the Sport version is back in stock)! I'll be watching Hope it all goes well
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Post by sbwnik on Apr 11, 2015 20:42:28 GMT
That's been a similar idea to my long term plan for OCO, but using a Harry Barlow top end for a bit more poke as well as increased torque. What running gear/improvements are you planning? I don't see the point in shocks that cost hundreds for a tourer, and saddlewise I've yet to find anything better than an MY seat. Out of practicality, I'm going to find a Mk1 tank and get a fuel sender added for the slight increase in capacity at the cost of autolube.
Ideas?
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Post by henri on Apr 11, 2015 20:50:51 GMT
the sip or bgm taps with low fuel sender ,easier than fitting a sender , but then you'd have a defunct gauge on ya speedo, not unusual on a p series . am interested in the mods ya planning guru ,as i'm bout to build a cosa200 , pretty equivalent to a px200 , have a new barrel/head/piston to play with , but was considering not using the new standard crank n long stroking it , am seeing your keeping the stock crank , any info/tips appreciated an probably copied ,with permission of course , H
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Post by sbwnik on Apr 12, 2015 20:23:04 GMT
Is that the type with the narrow nose? I don't find them as comfy as the previous one, nice enough but not quite.
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Post by sime66 on Apr 13, 2015 7:43:34 GMT
At what level of tuning does the hard cruciform become a good choice, pxg?
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Post by pxguru on Apr 13, 2015 18:19:14 GMT
Nik, I like those ajustable Carbone front shocks as an economical decent shock. Apart from what I have said already it will all be standard, looking standard (with back rack) and ingood working order. Eventually will have tubless rims but thats it. H, 57mm crank suits what I am doing. With a 60mm crank the standard barrel would need a bigger volume head and would end up will less bottom end. With the 57mm I should be able to keep it all but spread it out to 7000rpm. Sime, About where you will be is where either is ok. I expect this one to need it
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Post by henri on Apr 14, 2015 7:36:04 GMT
sounds more like what i'd want myself ,was considering stroking to try n give it "longer legs" ,but not if i'm going to lose bottom torque ,guess i'd have to kit/port it to try for both , an sime ,the reason the cruccys soft is that it gets the damage rather than loose gears ,a hard cruccys used so that at higher bhp the service interval isnt radically shortened .but as most tuned scoots get regularly torn down an revamped anyway with cruccy being replaced i'd only use a hardened 1 on a higher bhp tourer type scoot . where your not going to be crashing through the box in drag starts/sprints .an want 1000's of miles between service intervals/case splits . where there used in sprints/racers most are swapped out with the loose gears every 3-4 meets/races anyway.on a tourer that would make a service/re-build rather expensive ,so long as you keep a steady hand on your clutch a hardened cruccy might be a wise choice ,but if planning some "red light banditry" i think i'd stick with a soft n accept the shorter but cheaper servicing/replacement . h
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Post by sime66 on Apr 14, 2015 17:57:18 GMT
Thanks both, for this info; I don't yet know which I'll do - seems wiser to accept changing crux every couple of years than splashing out on new loose gears, but it depends on what sort of a beast I end up with - and how frequently I feel the need to Hooliganise the town; no hurry - I'll think on it for a bit and weight it up, and pick it up on my thread when I get to it, and leave this thread for pxguru's creation.
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Post by pxguru on Apr 15, 2015 3:24:06 GMT
Exactly what I think H If you race or are a gear box animal, then use a soft crux but in a tourer with decent cogs and someone riding who can change gear, then with a hard crux its going to be 10,000+ before it needs doing again. And once this is done I want to just ride it for years as my "reliable scooter". Bear in mind you don't get too many crunches on a hard crux before the cogs are mincemeat. If a 60mm crank is fitted with no base packer at all and no porting, then the bottom and mid will improve but the top end will suffer. As always a difficult juggling act of compromises between crank stroke/packers and port size/port timing to get the improvements you are after without too many of the losses. I think I have the balance right with what I plan. As I go on I'll post pictures and Micro Dyno charts to see how I do. The only parts being added that are performance related are the SI26/26, a Grand Sport piston in a PX200 iron barrel and a SIP Road II. Nothing else apart from porting.
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Post by henri on Apr 15, 2015 7:31:23 GMT
a gs piston eh, the 1 thin ring variety i guess , let me guess a exhaust port like a storm drain , some reckon you can go out to 70% on a polini evo/worb5 smallie barrel , probably more than your planning tho, will follow with interest , H
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Post by sime66 on Apr 15, 2015 7:33:36 GMT
I was just writing the same thing - When you’re in the mood, or when you come to it, you’ll have to show us what you did to the Grand Sport piston; someone on here was asking about that recently and got me curious.
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Post by pxguru on Apr 16, 2015 3:48:31 GMT
I must admit I have been planning this new scooter for quite some time. I ported the PX200 barrel and got it re-bored with the 1st oversize GS piston before I brought the scooter to fit it to So this is already done. I have a few hours tidy up and chamfering to do before it goes on but apart from that it is ready. I'll post some photos, port maps and dimensions when I finish it. I have moved the transfers and boost port up a few mm and took a lot of metal out of the exhaust and stub area but still keeping within the spec of tourer and hopefully not losing the bottom end The Grand Sport piston is just an upgrade from the standard one. Probably more reliability than the original too. The big differences are that its a lighter piston (more power with less damage to itself) and these ones have 2 thin piston rings. The thin rings allow the exhaust port to be a lot wider and don't blow by anywhere near as much as the fat ring standard piston does. I tried tuning with a fat ring piston to see what could be done, a few years ago but it just cracked up under the strain. If ever changing a standard piston the GS piston is more expensive but a quality part and better than the original in every way!
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Post by pxguru on May 9, 2015 17:06:49 GMT
latest; Parts delivered - 3 new cogs, banded clutch and SIProadII. Just need to get on and split the engine now.
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Post by sime66 on May 9, 2015 18:38:03 GMT
Looking forward to quietly observing this one..........
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Post by pxguru on May 18, 2015 17:38:18 GMT
Got around to spliiting the engine in the frame today. All seems ok and as expected. More blow by on the rings than normal but the gearbox didn't have any surprises, totally knackered. New 1st, 2nd, 3rd and cuciform going in tomorrow. Freshly re-bored and tuned OE cast barrel going on and new SIP road II. OE Barrel tuned to TD 123 degrees Ex to 172 degrees with BD at 24.5 degrees. Squared off the exhaust port like Sime's and Squared of the angled main transfer tops. Leaving the crank inlet as standard for now until it is fully overhauled in the Winter. Will stick with the SI24/24 until its run in. Going to start on a 140 main jet and see what happens.
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Post by vespasco on May 18, 2015 22:03:31 GMT
Lokks like its not had much of a service history! And done whats its supposed to do..keep on running What changes in performance are you expecting when you come to alter your crank timings?
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Post by mickingle on May 20, 2015 5:24:49 GMT
I can add absolutely nothing to this thread but it's an excellent read. Looking forward to more updates, pics and results.
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Post by henri on May 20, 2015 15:49:47 GMT
heavy on the clutch was he ,the previous owner , crunchy , you going to ditch that dead-weight (starter motor) or keep in case long touring miles give ya cramp an a inability to kickstart it ,like god intended . am interested in how much work was needed to get barrel to have those timings , might be copy-catting a tad on my cosa200 lump, after ive hacked out the tiny exhaust port .i'll post a picture of piaggio's method of de-tuning to 10hp for german laws/market , you'll die laughing . H
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Post by sime66 on May 20, 2015 16:11:24 GMT
H – re, how much work to get those timings: Pxguru’s:tuned to TD 123 degrees Ex to 172 degrees with BD at 24.5 degrees. Squared off the exhaust port. (no inlet timing info yet) Mine: – as worked out between us all on my big thread (by just raising barrel and working on exhaust port due to my lack of confidence, skills – and remaining fingers after last year): TD = 122.95 ED = 172.58 BD = 24.81 ID = 125/55 …very similar numbers with little work on mine, but it depends on the barrel and what you have to start with after a measure-up really. (I don't want to mess pxguru's thread up with random posts, but I'd already noticed the similarity in the timings)
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Post by pxguru on May 20, 2015 18:32:08 GMT
The one differance is that I moved all of my ports in the barrel, there is no packer on mine just a standard 0.1 base gasket. Exhaust moved from 39mm to 36.5mm and widended from 37.5mm to 41mm. Main transfer ports moved from 49.5mm to 47.3mm. A big pile of swarf was made. Inlet timing is totally original at 107/57. For now I will use the standard head with the big fat squish, SI24/24 and see how it performs. I will use it for mostly round town and long runs so very interested in economy and comfortable performance but the ability to do over 70mph (on GPS) if needed. let's see what happens once its run in. Still getting used to the SIP Road II sound, its a bit fruity
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Post by sime66 on May 21, 2015 5:34:54 GMT
I see that now, but it’s left me pondering overnight, so I'll ask. I’m interested to know how you would decide between raising the barrel and raising all the ports; I imagine it’s different factors each time, but specifically to your tourer. You’ve saved the cost of skimming (for now at least) and a packer, in preference for a lot of cutting in the barrel. I know you’re vastly more competent with the cutting, so that’s a major factor; is it because with raising the barrel you’d be cutting the ports anyway to get them correct relative to each other (your exhaust up 2.5mm and your transfers up 2.2mm), whereas mine just about worked out with just raising and keeping TD and ED the same relative to each other? Have you left yourself more options when you come to sort squish and compression ratios? If you'd raised the barrel and just moved the exhaust 0.3mm you would have had to skim it; is that it? Assuming what you’ve done is better because you can, what other advantages or savings has it given you? ie., if I were to do it again, what would be the other benefits of doing it by raising all the ports rather than a packer?
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Post by pxguru on May 21, 2015 7:41:39 GMT
Interesting question but with no exact answer. Changes to the transfer ports are sort of permenant. If you are sure about what you are doing and will not need to go back or adjust the barrel height then transfer port moving is the way. And no need to do any skimming if you don't want to. Using a packer and not moving the ports much gives a lot of options, the biggest one being you can put it back as it was. H, I like to keep the starter, very handy if stalling in traffic All other times I use the kickstart. What happened to that German tuning info? Should be good reading.
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Post by henri on May 21, 2015 9:02:16 GMT
still trying to re-find the pages my midnight insomnia took me too, the 70's jap stuff was better but all about disc induction , an written in english , the german forums n tech stuff gets pretty mangled in google translate often , H
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Post by vespasco on May 21, 2015 17:32:57 GMT
For me it would come down to trying to set it up how i wanted it with the least amount of machine work involved. Which in the end, for me, comes down to deck height... And to a certain extent, Whats happening at BDC. Setting it up with a suitable deck height to suit different, readily available heads would be a major influence...not much a reason really! When i first built the Pinasco motor, rather than porting and skimming the cylinder, switching to a long stroke was my answer to getting all the existing ports open... Even although it gave me not so great timings.
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Post by pxguru on May 31, 2015 19:40:04 GMT
The tourer was all back together and running a while ago. All working fine and running very well. Feels nothing like a standard 200 with the tuning and SIP road but still has very decent bottom end. All indications are that the port durations are working well. Still got to run it in as it has a new piston and re-bore, so running it really rich (spluttering a bit so it won't rev out) and putting an extra drop of oil in the tank as well. Not good for the environment or economy but the first few hundred miles are dodgy on a new cast bore. The difficult thing at the moment is riding slow enough and is very hard to keep down to less than 50mph on the flat. Away on business now so won't get to run it in anymore for some time. Feels like its going to fly once jetted down though
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Post by vespasco on May 31, 2015 21:21:33 GMT
Good news! Remember to keep the throttle at ease ! So no bottom end loss! Thats also good news! Keep us posted when its run in Im looking forward to hearing how it performs
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Post by sime66 on Jun 1, 2015 6:39:04 GMT
......an example to us all with your px-magickery!
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Post by pxguru on Jul 21, 2015 19:56:46 GMT
Tourer is all run in now! Pleased with the progress. Makes 60mph in 3rd on the vespa speedo. Torquey enough and rides fine two up. Enigne mounts are a bit wobbly, so over 70mph on the speedo is enough for me, until they are changed! Put a spare 26/26 carb on it. 55/100 pilot and 160/BE3/128 main jet, no air filter. Timing 18 degrees, Ok so far but needs work. Clutch is grabby and hard to change down gears, front disc makes a funny noise. Will sort these two problems next.
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