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Post by vespasco on Apr 9, 2016 19:07:00 GMT
*those little cut aways on the corner of the slide, for the progression have very fine tolerances.. i read you were contemplating 'making' your own.... just thought i'd mention it. even although you've probably got a little mini-workshop in your lounge and are more than capable these days.
i can always send you my no.5 if its any help but i may need back at some point.
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Post by vespasco on Apr 10, 2016 5:44:27 GMT
nothing to do scooters but.... its important its 06:43 and im awake
thats all
good morning
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Post by sime66 on Apr 10, 2016 6:12:30 GMT
You beat me! 07:10 - logging in for morning coffee and catching up on here before venturing out to tweak and ride. I see you were busy last night; full of enthusiasm after long break, while we were slogging through the Winter. Good morning anyway...... Edit: Just briefly, re slides: I read on another forum, (where you’d previously been – as usual), that you reckoned cutting a slide was a bit risky, because of precision required and cost of replacement, and I’d made my comment here before I realised that a #07 won’t fit in my carb – I have spares of those and they would have been good to experiment on, I think I could have copied an #04 Progression notch on an #07 though, and had top-pockets and no cut-outs to try: modernvespa.com/forum/topic83093Thanks for offer of #05, but I’m still undecided about this no cut-outs slide option; I didn’t have much joy with the bunged hole yesterday – still getting too hot too quick on silly little blasts (with 142MJ). This morning I’m back to basics; setting up my Pilot at my leisure in a quiet (for a Sunday) industrial estate, and maybe going back up to a 48/160 to see if it helps. Only a quick tweak this morning because, for me, today is dedicated to Paris-Roubaix on telly – lazy I know, but it’s special.
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Post by sime66 on Apr 12, 2016 10:22:04 GMT
My back is playing up again, so no progress here, and instead of tweaking I’ve been reading. This might be obvious to some old hands, but I think I’ve got my head round Si slide numbering now, so here’s what I have; There are two sizes of Si slide:24mmx42mm = Si 20 (and others 20.15, 20.17) 27mmx43mm = Si 24 & 26 (E and G) Some older carbs use the same numbers as current new slides, so the numbers appear in both tables, but the part numbers are different, and many are redundant (to buy, but you might still find them in a carb). References below are from SIP (Piaggio too?), dimensions are from Scooters Originali.com – I’ve checked an #07 size, but could do with a check of a 24 or 26 slide. Here’s the info I’ve found so far, when the 24 & 26 slides available are narrowed down (in bold for starters; 01, 04, 05, & 08 ?), I’ll try to identify which have top pockets, cut-outs, progression notches or pockets etc…(I think we have the info for the 24/26s, except for 08)…..: 01 (20) = 68230100 = Vespa 125 VNB6/GT/GTR/Super/150 Sprint/V./Super/P125-150X/S 01 (24) = 84920100 = Not available (see SIP 04s) = 200 Rally/P200/PX200E 1°
02 (20) = 68230200 = Vespa 150 VBB2T 02 (24) = 84920200 = Not available (see SIP 04s) 03 (20) = 68230300 = 180 Rally 03 (24) = 84920300 = Not available (see SIP 04s) 04 (20) = 68230400 = Not available (SIP links to 03 (20) = 68230300) = Vespa 125 GTR/Ts/150 Sprint/V/P125-150X 04 (24) = 84920400 = Not available (see SIP 04s) = P200/PX200E 2°SIP: 4.0 (24) = 84920400 = P200E/PX200E 2° 4.1 (24) = 84920410 = P200E/PX200E 2° 4.2 (24) = 84920420 = P200E/PX200E 2°05 (20) = 68230500 = Not available (SIP links to 03 (20) = 68230300) 05 (24) = 84920500 = T506 (20) = 68230600 = Vespa P125X (USA) (PR)(AUS) 06 (24) = 84920600 = Still listed - no info - no image ?? 07 (20) = 68230700 = Vespa P80-100E/X (D)/(F)/(FG) 08 (20) = 68230800 = Vespa P125X 08 (24) = 84920800 = Vespa 200 Cosa09 (20) = 68230900 09 (24) = 84920900 = Not available (see SIP 04s) 10 (20) = 68231000 = Not available (SIP links to 09 (20) = 68230900) = Vespa P80-100E/X (D)/(F)/(FG) High Altitude 11 (20) = 68231100 = Vespa PX125E Lusso/`98/MY/`11/Cosa 125 12 (20) = 68231200 13 (20) = 68231300 16 (20) = 68231600 Any errors or additions, let me know and I’ll correct it. Here’s the SIP table: Below here I’ll add images for what we have for 01, 04, 05, & 08 when I find one – I don’t think I’ve found anything new; just got it all in one place, and in my head now…..
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Post by vespasco on Apr 12, 2016 10:40:46 GMT
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Post by sime66 on Apr 12, 2016 10:44:48 GMT
Yes I saw it; still lots of info to come out yet, and price - blimey!!! I'm afraid it got me thinking about other 'big-boys' carbs, then I went for a cry and a lie down - 'cos I don't want to play with carbs anymore.....................
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Post by vespasco on Apr 12, 2016 10:55:41 GMT
hahahaha
ive a funny feeling i will be tinkering with my carb some more, i can't quite remember being 100% happy with it, as its more on the ragged edge than safe...... when i eventually get it out of storage that is
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Post by henri on Apr 12, 2016 11:16:09 GMT
seen a maybe price on those 30mm , as somebody else commented "never thought i'd see the day a 30mm pbhl dell n manifolds cheaper than a spaco" . an i believe you also need a 37euros bigger tray lid for the 30mm ,an probably a bigger wheel at headset/tube end . H
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Post by sime66 on Apr 12, 2016 16:59:18 GMT
I’m in a similar position, vespasco, balancing performance and cylinder temps, - not ragged edge, but hotter than I’m happy with; if I have to chose, though, I really like my low-revs acceleration and easy climbing, and would sacrifice some top-end speed to keep that (I got 116kph GPS - 72mph - while you were away, but not getting that now). My 2nd and 3rd are fantastic at the moment, but my 4th is a bit sad with the current jetting – Main too big. Still playing with tweaks and options to get optimum for all, including the slide options, don’t expect to have to compromise really, but happy to keep it safe and play at my leisure, especially as it’s (hopefully) getting warmer now too (for those who spent Winter here). I think I’ll possibly end up changing my Pilot back, or losing some of the extra drills in my BE3 – I need to read back when and why I changed each item and what difference it made. H, I’ve only just cottoned on to these larger throttle pulleys and quick action twist grips being for bigger carb slides; I’ve been noticing the need to twist further for the 26 carb, but hadn’t twigged why until now, with this and the discussion on kidda’s slide thread. I saw that price and comment too about the Si30R, the other day, but can’t be arsed to look for it again; it was something like €250. I won’t need one anyway, but it’s interesting; keep an eye on SLUK, I’ve had a quick search elsewhere online and haven’t found anything else yet. Overview of Pinasco Si – ‘R’ carbs here – not 30R though (use Google translaste for the page): www.pinasco.com/index.php/rubrica/news/carburatori-rPinasco 2015/16 catalogue here (nice bit of scooter porn, actually): www.pinasco.com/pinasco_catalogo_2015.zip
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Post by sime66 on Apr 15, 2016 6:33:09 GMT
For some while now, I’ve been wondering if I might have an air leak, as a factor in my high temps, and a few days back she started revving pretty wildly, but I got home and did find that, although the carb bolts were tight, my slide wasn’t closing properly, so I took the carb off and the fillet screw and carb box were loose. I took it all apart and cleaned it up, threadlocked the fillet screw and torqued the carb back down; the slide moved freely and the revving was sorted – but not the high running temps…… Yesterday I had a go with the 48/160, took it for a blast (hot), set the Pilot up when warm, and took it for another blast, and it’s still too hot – 142°C just quick WOT between villages. Although I’m going through the process of switching stuff back (richer – BE3+1, AC160, 145MJ) to try to get temps back down, I’m beginning to think that there is something else causing it, because lately things I’ve expected to reduce temps (Pilot, bunging the slide air hole etc.) aren’t doing so, in fact my temps seem to be getting higher. I suppose I’m going to have to check my flyside seal too, and I’ll make new carb gaskets, check the carb is flat, and redo the carb job properly at my leisure rather than quickly roadside, but from those symptoms and this image below, which shows a little oily residue at the bottom of my cylinder head, do you chaps reckon this is a normal amount of crud, or worth investigation? The head torque is still spot-on though, but maybe a bead of Hylosil250 might guarantee it – I know there shouldn't be any, especially as mine is freshly machined. It might be interesting to have a look at barrel, crown and combustion chamber after about 2,000km too, but I don’t want to disturb it all for the sake of making work for myself. I should say, that other than the dip in 4th WOT performance, expected due to overjetting the Main, it is still running and pulling really well; climbing and acceleration, so it can’t be much, but it is getting too hot. I cleaned up properly around the plug and CHT ring yesterday too to see if that crud comes back, but you chaps have convinced me a leak there is unlikely. Also something that might suggest a bit of a head air leak; it always starts really lively, but always second kick, never first. Here’s the bottom of the junction between head and barrel – shall I open her up? Either that or keep going richer unti lI get on top of the temps, but I'm beginning to think that isn't the answer:
I also had an odd, bright orange side to the plug:
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Post by pxguru on Apr 15, 2016 15:38:34 GMT
The head can't suck air in and poor starting hot is usually too rich. If you had an air leak it would run hotter.
142 deg C is good. Try to get it up over 150. It's run in enough now.
Try going back to the 160 AC and see what happens. Its a lot of messing about but once its right you get to ride it all summer.
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Post by sime66 on Apr 15, 2016 18:37:41 GMT
Thanks; I’d rather be out riding about with a bag of jets and plugs, than in the garden messing with me tools and bits of engine any day, so I’ll carry on as planned then. But, I think, and will try to show in the morning, that keeping it under 150°C will be difficult with current jetting unless I'm riding with caution; over 150 & 160°C will be easy to show. The 142°C above is on a short stretch where I’d prefer to see 125°C, and 133°C there previously gave me 160°C on the 5km dual carriageway run – and a plug later described as ‘dangerous’ (p18 March 12th - with Polini vortex, RamAir filter, 48/160, 138MJ, BE3+2, 170AC - and 5°C ambient) I reckon I’m about 20°C high there on previous good runs, and 10°C up on the ‘dangerous’ run, but with a bigger MJ and 9°C ambient. I’ve definitely got too high temps and a shabby 4th at the moment with my recent tweaks, and I’d convinced myself that something else was going on, but after my blast in the morning, I’ll start with the 160AC and just keep tweaking it down. ......I'm still riding all the time and enjoying it, just aware of something, and a bit stumped about sorting it at the moment.
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Post by sime66 on Apr 16, 2016 6:25:19 GMT
Just quickly, I'll add detail later with an edit; a warming up run, which got me to mid 130s°C, followed by a 3km dual carriageway WOT blast got me to 157°C (315°F for those who started the Spring Term late; you know who you are!!) and only 105kph GPS max (65mph). It's as I expected; hot, and sleepy in 4th (with 142MJ). The Plug looks much better than from the 160°C run I had before though; I'll add more detail later. I do wonder, from reading elsewhere, if the 150°C safe max is a bit cautious. Still sticking to plan, but ideally want the temp down, and the 4th gear back how it was...... (Maybe mine is just going to be a little hotter than expected, and as weather warms up I'll maybe get back to 45/160 and 140MJ). Edit: - A little bit of detail: Weather conditions:Precip: Cloud (40%), Showers Pressure: 1005mb Temp: 5ºC Wind: N – 15-22 knots Current Jetting Magickery: Polini vortex, RamAir filter, 48/160, 142MJ, BE3+2, 170AC, obstructed (04) slide air channel.Max temp with 3km WOT = 157ºC, but max speed was only 105kph GPS. Plug (I know these aren't WOT plug chops, but they still give a good idea alongside temp records):
Does not look lean at WOT, maybe temp is actually OK, but speed is definitely down. I think it was better lower down with the 45/160 too, so other than the temp (which is only shown on this gauge and possibly not excessive anyway, but might be again if I get the 4th sorted) it looks like I could go leaner a bit on Pilot and/or main, or try again with unobstructed slide air channel. I don't think I want to change the 170AC. Maybe I could just leave it alone for a bit before tweaking Pilot and Main later.
False alarm yesterday; at least I'm not chasing air leaks, just fiddling with jetting still. I'll just go back to riding and tweaking, which I'm well happy doing; I didn't intend to give the impression that wasn't the case, I was just after advice about whether to investigate this possible leak in case that needed sorting first, so thanks for that.
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Post by vespasco on Apr 16, 2016 15:06:39 GMT
with regards to your 'leak'..... the residue you see on the head...is that from the exhaust? was it from the head? im not sure how many miles you've clocked up with that head fitted but if its more than say, 1000, then it may well be worth having a look inside if you have an excuse to do that..... i used to find that every 1000 or so miles my head needed a re -torque and sometimes a good clean (more so as it is a pinasco which are sometimes liable to ping) you may still need to re-torque the head anyway, depending on how many miles you've clocked up whilst in your shorts and in the snow/wind/rain - dedicated or mad? you decide. plugs look safe to me. As you get used to your temp gauge you will notice a slight difference depending on the ambient temps, for what ever reason. i remember using hylomar/wurth 250' sealant with good success but it was not a permanent fix... although it lasted longer than with no sealer. The fuel and heat eventually made its way out the head joint .. a little extra on the torque wrench soon sorted that - as the combustion chamber was made smaller - more pressure on the joint - made it prone to leak a little more than i'd like. i still cant find my Hong Kong Book of Kung-Fu, the Vespa Edition
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Post by sime66 on Apr 16, 2016 18:28:54 GMT
Mate, I really hope you find your little black book; that's a real bugger. It's got to turn up though, eh. I think we've discounted the possibility of any head leak; torque was still spot on anyway, source of unidentified muck remains unknown, but if I don't bother to clean it off I won't notice it coming back, so gonna leave well alone for now. Yes, although speedo hasn't been working all the time, I'm deffo over 1000 Miles easy – (are you going to insist on ºF, MPH, Foot.Pounds, Pounds and Ounces, Gallons, and Feet & Inches then? - we have been metric for over 50 years now). Anyway, I decided to compare today's numbers with previous best from last Month, and here's what I reckon: 12 March – Page 18: Result - set-up #3: Polini vortex, RamAir filter, 48/160, 138MJ, BE3+2, 170AC**16.83PS @ 7760rpm, 16.28Nm @ 5631rpm, 8927RPM max (= 101kph = 63.2mph in 3rd) & 160ºC @ 115kph GPS.**^^^That was my best MD run with 'dangerous' plug; and today I was: Polini vortex, RamAir filter, 48/160, 142MJ, BE3+2, 170AC, obstructed (04) slide air channel & 157ºC @ 105kph GPS.So that's a bigger MJ and obstructed slide channel today, hence the lazy 4th, a much better plug, and slightly lower temperature (not much lower, really though) – both results recorded with same ambient temp (and long trousers). I'm just doing a recap to convince myself nothing is leaking, and that although I'm faffing about with this last bit, I am getting similar results, going in the right direction – rather than round in circles, and still close to finding - - - - Optimum Bespoke Carburation!!!! ...….it's just a question of finding which bits to tweak to get it closer; I think I'll do a 140MJ run again and see how my temps and 4th speed change – how high can I go on the CHT before I have to bail out and ease off though!? Also, although I had 48/160 in both of the above, I did like it with the 45/160 (or am I just imagining that I can feel the difference), so I'd like to try getting that in and set up again. - I did have 45/160, 140, BE3+2, 170AC before (p19), but not with the obstructed slide air channel, so maybe that's where I'm heading with this (then maybe back to slides)....... No worries anyway; just thinking aloud, and recording it here, so I remember what I'm thinking and doing as I change things, and if I need to read back some time. I reckon I'll take more notice of my plug, and allow a bit more leeway with the CHT in future. I bet you find it in the last place you look!
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Post by vespasco on Apr 17, 2016 21:53:20 GMT
My notes will turn up some time, no worries and when i find them, they will be in the last place I look, that's guaranteed. Admittedly i do use degrees f rather than degrees c but only on my sip temp gauge and only because f' degrees effectively reads on a 'faster' scale than celsius. Even my satnav is set to Km, waiting for the day we do actually turn fully metric. Glad to hear you are reaching tuning nirvana now and that 3rd gear top speed! wow! nice. i've also been re-checking my jetting this afternoon (finally) after re-reading some of this thread I had 55/160, 160/BE3/150. now i have 50/120...but i could not find all my jets to get it to O.B.S. I'm still not quite satisfied but tbh, don't laugh sime, I was getting cold! so bombed it home...although i did take the scenic route! (I wasn't even wearing shorts, I had loads of layers on) My temps maxed at 275'f (135'c) (but remember my sensor is tapped direct into the cylinder head). I was concerned about the fuel thats been sitting for 5 months so drained that, by riding slowly, then filled up with fresh fuel... still about the same temps but now with the 50/120 i have a very slight, ocassional stutter around 3000rpm. OBS is close but there is still some tinkering for me too
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Post by sime66 on Apr 17, 2016 22:18:45 GMT
I was just about to take Pauline Black to bed! (her book, that is) But then this post turned up, just as I was about to turn everything off. I'm going to look at your numbers better in the morning, but your jetting all seems a bit safe; is it? ....stutter at 3,000? - get your little drills out!! I'm messing about; I'll have a better read and cogitate in the morning; Pauline's calling................... Optimum Bespoke Carburation can wait another day.........(I did nothing with my scoot today).
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Post by jimscoot on Apr 18, 2016 4:35:50 GMT
Hey Sime as always great work.
I've read some great reviews of the grand sport piston and how it doesn't expand so much with the high silicon content.
You can then run leaner, claw back some performance with higher temps but with a piston that can handle it.
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Post by henri on Apr 18, 2016 6:42:34 GMT
the GS piston is the one to use if possible everytime ,top quality thin rings an low expansion ali .wouldnt say you could run leaner with it tho ,more power from a engine=more heat generated already,just the GS can handle it .it does give a wider safety margin if your jettings slightly on the lean side of the curve,were other pistons are on there limits already an will seize . H
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Post by sime66 on Apr 18, 2016 8:28:08 GMT
I’m aware of the GS pistons, and would look at them next time. Remember though, that this was originally meant to be a budget build with the emphasis on the precise measuring, calculating and cutting, not a big-budget performance build; I only bought the new DR kit because it was very cheap from Italy, at the time I was after any old 150 or 180 to measure and cut. The entire engine is bits bought from friends on here, Ebay bargains, and my old spares. The budget idea went out the window ages back, but it was never about buying expensive stuff and bolting it together. I hope not to be replacing this top-end any time soon, and with a bit of care over this elusive performance/temp balance it’ll have a long and happy life. Overnight, though, what’s been bugging me is why vespasco has such rich jetting and still has a lairy engine; if we’re all aiming for the same stoichiometric combustion ratio throughout the rev range, and noting that his is a 225, where’s all the air coming from for the rich jetting? I read your Rally thread the other day, vespasco, but I was looking for something else, but I’m going to have another read of it; You’ve got conventional bellows and (partially de-meshed?) filter intake (maybe that’s it), You’ve got a 24 or a 26? Drilled-out? Maybe it’s your exhaust getting it all through the engine quicker? I know your timings are a bit wonky. Maybe it’s because you and your scoot are significantly lighter. Maybe it's because mines cast iron. Anyway it’s been nagging away at me and I shall wander over to yours sometime soon to investigate………………….. But; that’s all just idle curiosity; I’m good with what I’m doing – just riding and tweaking at my leisure, with a view to jetting it a bit leaner to get a better 4th again, allowing my CHT to get a bit higher than I was before I get too concerned about it, and letting my plug tell me what’s going on – unless there’s big jumps in running temps to ring alarm bells. Re-rereading you post last night; that 101kph 3rd gear top speed is calculated from recorded revs, not actual; when I have a significant GPS speed I put ‘GPS’ after it; (I'd have to read back to find a top 3rd kph GPS; it's easily in the 90s though; MD will have recorded a speed if the GPS** worked; I'll look back in a minute). MD recorded nearly 9,000rpm* in 3rd though, which I think we decided needed reigning in a bit! It was cold this weekend, my hands were a bit numb on Saturday morning too, but you are going to have to toughen up a bit now you’re back. How do you go from a 55/160 to a 50/120 – what’s your jetting selection method; a pick-and-mix bag? I know you ride fast everywhere, and given that it was pretty chilly, and that your CHT sensor is drilled in your head, you do seem to have a cool engine; it’s this that’s bugging me at the moment when I’m trying to keep my temps down so I can jet a bit leaner; I’ll investigate later. Edit:
Checked the GPS** for the WAV; the 3rd gear MD run did record 101kph GPS, which ties in with the 8927rpm* too:
(but the plug was pretty white and CHT was 160°C @ 115kph GPS - it's been toned down since then, and I'm trying to find the balance).
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Post by pxguru on Apr 18, 2016 9:37:05 GMT
It can all get a bit confusing for sure. To simplify it a little. The carb drilling from the MJ is very relevant. If its the same size carb with the same size drilling, then you can start to compare. I have found that once the mixture screw, pilot jet and progression are all set, they can be left alone unless there is a major change, as it will take something substantial to alter the jetting. Just need to concentrate on AC, MJ and Atomiser holes. Changing and testing one thing at a time might be tedious but gets you to OBS nirvana much faster in the end. Changing the AC is as sensitive as the MJ, as it alters the whole curve from 1/4 to WOT. The more air let in at lower rpm will be even more at WOT and less draw on the MJ. Sime, I think yours will jet in fine. It won't do 75 mph GPS everyday and for no apparent reason. Somedays are just faster than others
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Post by vespasco on Apr 18, 2016 13:58:28 GMT
im still impressed by your 3rd gear speeds. top work my method of jetting is.... apart from having only 2x other idle jets i can find to play with....is the same as setting up my ignition timing; start high, at say 150mj (or @ 22' BTDC for eg) then rather than going down in small, barely noticable increments and second guessing if it's made any difference, i would go down 2 or 3 steps/degrees, to make the change more , er, noticable.... that way i can be sure im heading in the right/wrong direction and then adjust in 1 step increments, back towards where i started/where it needs to be.... then i would start again going down 1 step at a time... hope that made sense! i do have an older SIP mkI pipe fitted, which gives way better acceleration but slightly less top speed than the mkII ...i prefer the acceleration personally as i dont plan to ride too often at top speed anymore...and its a hell of a lot more fun at traffic lights and coming off roundabouts etc so that could be one thing that makes a big difference. it will do 70mph GPS everyday but realistcally only on good days will it reach more...and @ more than 70mph it would start to feel a little unstable, especially if i end up slip streaming, so 70mph is just fine, its getting there thats the fun part as for temps..i dont know how its so cool... even my first Pinasco, with cht ring under plug, never ever reached more 225'f @ long WOT...and got cooler as rode, i can't seem to repeat that now that i raised the exhaust port but will some day. but the little play i had yesterday with the idle jet did show it was getting hot @ mid range throttle, so all is not perfect and i've not done any plug chops lately...i'll be happy when i see temps drop a couple of degrees as im riding (at a constant rpm), just like it used to, rather than slowly rising a couple of degrees... temps seems fine cruising at below 1/4 throttle the slight stutter i mentioned..it is very slight and sometimes only, im being picky...but none the less there is room for improvement to get it to OBS. and ive a feeling my carb could just be a stock 24mm carb, no drilling, i really can't recall until i find my notes.,,which could be the reason for the large 150mj.... im still going to play with carbs... as i know i can improve on what i have (even if only to make it safer) and i'll carry on waiting for Bipasha Basu to write a book ;P at least this pic is scooter related
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Post by jimscoot on Apr 19, 2016 5:28:59 GMT
Just thinking outside the square here Sime but is their anyone you can compare your scooter against like a friend that has a kitted scooter or maybe some of the guys you ride with surely have kitted scooters you can compare with.
At least then you know where you sit and in the grand scheme of things you might be surprised that your scooter is very quick and you can actually be happy and content with your work and performance gains.
Your quoted GPS speeds are very impressive and I would be very happy with those temps.
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Post by sime66 on Apr 19, 2016 8:32:00 GMT
Jim, I'm already delighted with the build and performance results; this last few weeks has been finessing, and there is still a better performance/temp balance to be found, but it is fantastic as it is too. I am beginning to think that higher CHT temps on this gauge on this engine are going to be OK though - my plug suggests so. My scooter is incomparable against any of the limp poovery the locals pass off for kitted/tuned scooters here! Vespasco, Bella!!How's that Jamboree Bag of jetting going? Need to borrow anything? I also am not too excited about top speed, other than to see what it does, but love the rabbit-chasing nippynes, hill-pulling, and acceleration; mine does a little over 70 of your old Miles per hour on a good day (116kph is the highest I've actually seen on the GPS in 4th = 72mph - [in 3rd =101kph/63mph]), I've got a new front end wobble that starts at about 90kph though, which I need to investigate some time – it never used to start vibrating that low. Mine would perform better with a lighter pilot of course. Not for this build, but I'm starting to feel my way into 'Big-Boys' carbs too; just out of curiosity (and for future?); the Dellorto serial numbers (esp the suffixes) are still a mystery to me, and the Oko and Kehin even more so, and they'd all need another load of stuff for your Jamboree Bag of bits. I think my playing with these carbs will be of the investigative and theoretical kind for now, rather than the dirty hands or riding round in circles tweaking kind. Also I think, for me, pointless without an expansion pipe anyway, which I don't want to do, and anyway I'm happy as I am – just curious. Pxguru; I am very pleased indeed, and I also have no doubt that Optimum Bespoke Carburation is imminent (has been imminent for a while); my little self-doubt over the phantom air leak is in the past; and I'll just tweak as I go now. I do take the point that I should not keep fiddling with my Pilot though; I'm not sure which of the two I'll settle on, but once I have up to Progression spot-on that tweak will be out of bounds, and I'll concentrate on AC, BE and MJ only. Maybe I will need to lose a bit of low-rev nippiness to get my 4th back – but not much! I'll just repeat my narrowed down table of close options again (for myself really) to show where I'm at with it – current selection in RED: Si 26/26 (drilled to 2mm), Polini vortex, RamAir filter, and....48/160 – 45/160 142 – 140 - 138 BE3 – BE3+1 – BE3+2AC160 – AC17004(Obstr) – 04 – ? …....and my main thoughts, in layman's terms, are that I'm too rich at WOT, but my hot-spot is not at WOT, so I want a bit richer in the middle and leaner again at WOT, so what to do to let me put the 140MJ back in (AC160?, maybe the 45/160 first?) – that's what I'm thinking......... (one at a time though, obviously – no pick and mix, lucky dip here!) Chaps, don't take my witterings to suggest a problem; I'm just tinkering and tweaking at my leisure, keeping a record here, and replying to points raised – it's all good! Edit - (20-04-16) For my own records mainly, and not wanting to keep making new posts that mislead anyone into thinking there's any problem; I was outside replacing my speedo cable (again!), so thought I might as well tweak the carb while I'm there. The thinking here is I really want the 140MJ back in to sort my 4th WOT out, but need to compensate somewhere to keep my temps sensible, so did the 160AC too (to start with, but might change back); I'll try to have a rev-range/temp run in the morning - out of time today. This is my jetting now (changes underlined).......... Si 26/26 (drilled to 2mm), Polini vortex, RamAir filter, and.... 48/160 – 45/160 142 – 140 - 138 BE3 – BE3+1 – BE3+2 AC160 – AC170 04(Obstr) – 04 – ?
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Post by pxguru on Apr 20, 2016 17:48:09 GMT
When the pilot is corrct there are a few clues. Assuming it runs fine and plenty good enough, how do you tell it is actually the right pilot? First, it will start first kick when it is hot after it has been stopped for 5 minutes. Second, When closing throttle from very high rpm after being thrashed hard, it will get down to tickover without too much delay or hesitation. Third, when riding at 2mm throttle it feels right and doesn't cool down the CHT too much. Fourth, the mixture screw is at least 1.5 turns out. Can't think of anything else but there must be more. Once the pilot is does all of this, leave it alone! Will just confuse the hell out of you when you are doing the other stuff. If the pilot doesnt do all of this then the rest of the tinkering will be un-clear. Was inspired to give my Polossi the Summer re-jet today. Changed the atomiser one size smaller, needle up a notch and a half. Dropped the pilot by 4 numbers. Goes like stink again. Was a bit windy out but it screams its little heart out again and even wobbled its way up to 83mph GPS round the bypass. Well chuffed
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Post by sime66 on Apr 20, 2016 19:20:55 GMT
Blimey! That’s some fancy big numbers, even in old money. (= 133.5kph). Splendid day for a good blast too - if a bit breezy. ‘needle up a notch’ - you see talk like that gets me more curious……… For now though, back to my silly little Si carb; thanks for the Pilot check-list reminders ( just for interest and as you took the trouble to write it): 1) It will start first kick when it is hot after it has been stopped for 5 minutes. (normally 2nd kick, hot or cold - rarely 1st, rarely more)2) When closing throttle from very high rpm after being thrashed hard, it will get down to tickover without too much delay or hesitation. (Yes)3) When riding at 2mm throttle it feels right and doesn't cool down the CHT too much. (feels right - smooth, it was quite cool before, hence leaner Pilots – need to check Progression temp and plug again properly since last few changes)4) The mixture screw is at least 1.5 turns out. (14th April: 45/160=1¾, then 48/160=1¼)I’ll be out tomorrow, mainly for a decent ride, but I’ll spend some time on the Pilot before moving on from it - the small tweaks I did elsewhere today won't change that. Sadly best weather was today, but have to make time when I can. ......Will we see an MD for your tourer sometime?
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Post by pxguru on Apr 21, 2016 6:59:15 GMT
The way yours is running now it is clearly good enough to live with but you can see from the check list...actually it isn't! 1) They rarely start first kick when cold and this is expected and normal. First kick cold might indicate a small fuel leak? When hot it should be first kick. Even half a kick. If everything else in the engine is good the pilot jet is too big. 2) Good but it will only hesitate if too lean. Too rich or really rich still work fine here. So the Pilot jet isn't too small. 3) If you are riding round at 140C and all good then cruise at 2mm throttle for a while, the CHT temperature will drop but should not drop below 115C. Sounds like yours is; pilot jet too big. 4) This is pretty clear. It's too big. The tourer lives at a different house. Remember when I was jetting it a while back, I brought 4 pilot jets all progressivly smaller than 55/160.....needed one more size down. I now have a 45/160 for next time I am there. Will MD after that
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Post by sime66 on Apr 21, 2016 7:51:57 GMT
Nice when it's so clear, thanks. I did feel that I was happier with the 45/160; I'd have to read back to see when and why I changed back up, but I'll change it back again anyway. Probably leave the rest as it is for starters, easy enough to change as I go now, so (for me to keep track):
Si 26/26 (drilled to 2mm), Polini vortex, RamAir filter, and.... 48/160 – 45/160 - 42/160 142 – 140 - 138 BE3 – BE3+1 – BE3+2 AC160 – AC170 04(Obstr) – 04 – ?
I have a memory that you thought the BE3+2 wouldn't be so effective with AC160, but I'll fiddle with all that once Pilot is correct. I'll stick with 45/160 and try to get it so the 140MJ can stay too. Anyway, it's just final fiddling now.
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Post by pxguru on Apr 22, 2016 6:23:25 GMT
You might even find that the 45/160 is too big. For the small number (the petrol part) the turns on the mixture screw are the biggest clue. The point where the revs speed up the fastest as you wind in the mixture screw should be 2.5 turns out (on the fine thread screw). If your pilot is too rich then this could be why you might need the BE3+2 and AC170 at 3000 rpm. When the pilot is too rich it affects the whole set up and makes things confusing. If you can get back to the AC160 you won't need a new slide I am thinking the similar for my Tourer. Once I get the smaller pilot fitted I might need less ar as the main jet comes online.
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Post by sime66 on Apr 22, 2016 8:45:38 GMT
I set my alarm for 5:00am this morning to have a ride before the day started, but it was pouring here, so I had my coffee and went back to bed! – So no testing, and it’s a busy day today, but forecast is good for Saturday. I have got a 42/160; I’ve now put in the box of jets I carry with me, to try next if Mix screw turns suggests it. I’d been keeping it up my sleeve as last chance before I’m off the scale, and also because before you did your last update on your tourer I’d thought I must be doing something wrong to be at the lean limit of available Pilots, or that the 2mm drill had proved to be too much, but I’m reassured you’re finding similar results with yours, as I said on your thread. I’d also been aware that there’s more overlap between Pilot and Main over the bigger-air side (160) of the Pilot table, so maybe it’s having more effect, or affecting further up the rev range (AC, BE) as you say, and maybe the Pilot might make it all fall into place again (like 42/160, AC160, BE3, 140MJ and unblocked 04). If it gets too fiddly this weekend though, with too many changes and not enough time to test, it’ll just have to stay as it is; ‘safe’ until after the Bank Holiday weekend. . . . . . . . . The next post is the 600th on here, and will receive a copy of this new publication:
OK, so I had an idle half-hour last night and was bored with looking at wiring diagrams for other people’s scooters. (Just a bit of Friday Malarkey)
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