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Post by sime66 on Sept 29, 2015 10:10:09 GMT
….. I wanted to post this over the weekend, but had to give New-Best-Friend-Lathe-Man another couple of days to finish the job; there is absolutely no hurry anyway, but I was really keen to get that chapter behind me:
BUILD UPDATE...............
Engines all together:
but something was missing?
Ready for strobing:
Will have to remove carb again for presure test – doh!
2.0mm + 0.2mm; sorted Thanks anyway loon-e):
CHT gauge with a theft-deterrent bracket:
I've been planning some other wiring jobs while I'm running CHT cable through frame:
My barrel and head skim is done, and I'll get it back later this week, so it will be time to check the dimensions and volumes, double-check against the calcs, do some tweaks and tidies if/where necessary, pressure test the crank case, and ….................................................................... get the bugger in me scoot!!
End of September was my target, and that's what it's taken, with good breaks away from it at Easter and Summer holidays as well, so this seemed like a good time to update for anyone interested. I won't be giving a day-to-day updates from now on, but I've been keeping my Flikr album updated as I've worked on the job since Summer if anyone wants to PM me for the link to that, and I'll share my remeasure and calc-checks in a week or two for those who like chewing over the numbers. Then it'll be planning not having the scooter for a while, with swapping engines over, getting the new one running, reliable, and run-in, then jetted – and of course any unplanned but inevitable hurdles. Hopefully we'll have an “it's alive” video soon, and also some MicroDyno runs to add to the pot later on, or in the Spring – once again, for those that thought MD was worthwhile when we looked at it before – it should be an interesting comparison to a bolt-on DR if nothing else.
When I'm happy that the new engine is running OK and reliable, I have to split the old engine to do a few over-Winter jobs on that one. Maybe I'll be thinking about whether to give it a tweak as well, but that's too far ahead, and too many unknowns to think about that yet.
That's all – a new post with some numbers, soonish.........................
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Post by doulsy on Sept 29, 2015 12:34:05 GMT
Looks great, how did you get casing so clean?
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Post by vespasco on Sept 29, 2015 16:30:50 GMT
Brief build eh!!?? I just buy new ones personally
And yeh, youve done a good job of cleaning everything. Nice
I will nice to see the motor together once again
Hope it all goes well and waiting to see your moves around the garden when its alive.
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Post by djloone on Sept 29, 2015 19:12:12 GMT
Looks really tidy mate!!..if mine can get even close too that i,ll be amazed..pm me your flikr link plz some of your knowledge could be invaluable to me in my rebuild (im not in the least bit prowd when it comes too using someone elses knowhow to help me along)..i,ll be keeping a close eye on your work..looks bang on!
LOON-E
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Post by sime66 on Sept 29, 2015 20:04:31 GMT
I didn't use anything flash, Doulsy; they weren't anywhere near as bad as yours are. I just used very hot water, scrubbing and Gunk. Scotchbright-type pads on all the mating surfaces, which were also good too. It's not about shiny cases really (though those rusty ones of yours will need some work); it's putting decent component parts together with care that seems to make an engine build need doing just the once, rather than two or three times. Unless of course you're going to tear the arse out of it, in which case it seems it'll blow however well you build it, vespasco. There'll be no dancing I'm afraid; I shattered both my legs in an RTA about ten years ago – not the nimblest on my toes any more. PM'd you loon-e
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Post by pxguru on Sept 30, 2015 11:48:49 GMT
All going nicely to plan I see very shiney and green gasket, all good. Squish clearance will be nice and tight I hope. I always pressure test it with the barrel on too. Checks the base and head as well then. About 10psi max and see how long it holds up for. The first run in stage is always tricky when so much time/effort/money is at stake. First 200 miles is when you don't really want a heat seize. What works for me is; after the first start take it for a few 10 mile runs allowing it to cool down and go cold between each run. Run a main jet 10 points over what you think it needs, so it wont rev out. Add a couple of extra turns out to the airscrew, so its drivable but splutters. Add an extra 1% oil to the tank. Try to keep it in 3rd more than usual and not change up too quick. Then after 200 miles re jet it properly and do what you like but no long WOT thrashing or low throttle slow cruising (both very bad for a new 2 stroke engine).
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Post by vespasco on Sept 30, 2015 19:19:29 GMT
So your trick to getting them nice and clean is to use a pot of Elbow Grease too. Mine ran out ages ago. The constant rebuilding keeps them clean. hahaha Good tip on the running in. I'll be up-jetting from now on when i really have to take it easy. I think ive got a 165 somewhere
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Post by sime66 on Sept 30, 2015 20:04:44 GMT
10 psi for 10 minutes is the aim – I read back through the threads a while ago to check, which also reminded me I'm supposed to do petrol down the inlet to check the sealing pad too. My squish is intended to be 1.35mm when it comes back tomorrow. I think you'd reckon less would be better, but I'm not sure about going too low, and anyway it can have a tweak when I've measured it and the volumes again – but I'm not going silly with it (I have scoured previous threads for figures discussed before, and those agreed for mine – slightly higher is better for mid-range? Got to get compression at optimum too, which is about 10.5:1 at the moment – both with the 3mm skim). Anyway, I'll get my head back into the numbers with a fresh brain in the morning, but am intending to check rather than change the numbers. Thanks for the running in advice; I'll be following that very carefully. Rough and rich. I'm using a 120mj with the 24/24 in Old-Faithful at present, and I've got 128-140 jets (all Dell'Orto) for the 26/26 in this engine; I was going to start with 132mj, but that sounds like I should start higher? 135/138/140. ...….you'll have to drill your own, vespasco.
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Post by pxguru on Oct 1, 2015 5:17:00 GMT
1.35 is still a fine clearance for you. I think for constant high rpm action it should be more like 1mm but for city riding more like 1.5+mm. lets see where yours is tommorrow.
I would start the running in with a 140 main jet. The first tune of my Polossi three years ago used to run a 160 main jet in a 26/26 but once I tuned it again it was beyond the 26/26 carbs limit, which is why now have the VHSH go-kart carb on it. Once you have done about 50 miles be sure that it does actually splutter with the 140 jet, those are some decent sized ports you have now!
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Post by sime66 on Oct 1, 2015 10:28:55 GMT
Noted and actioned those; thanks. The other thing I should try to get right before I begin is the idle jet. I rechecked and in this 26/26 carb is a 52/140 (2.69), which I can only cross-reference as used in a PX80 according to SIP. I'm not very genned-up on idle jets (part of the learning to be done on this engine is properly understanding and setting up all aspects of Si carb – I know there's stuff been discussed and posted before and I will read back to see what gems I can find here and elsewhere), but again looking at SIP, I see a 55/160 (2.90) comes standard with a Spaco Si26/26/e. I also have a 48/160 (3.33), which I swapped out of the 24/24 a while back. I've got the air screw out a few extra turns (from 2.5 to 4 on Spaco) and put the 140mj in, but do I need a rich idle jet as well? Also I will need best guess at where I'll end up with it – those couple of idle jets is something I could organise now with a bit of guidance about where to start; any suggestions? Had to take carb off for pressure test, so I did petrol down the inlet – 25 seconds, which I believe is OK (that's petrol though, not 2-stroke oil), discussed here: vespa.proboards.com/thread/4450/edit-leak-test?page=1No numbers this morning – had a bit of a play instead.............. ......just having a bit of a read-up on idle jets, found this, and marked ^^those^^ jets on it:
...just trying to get a picture of what the numbers mean. I know I've read it up before but I don't seem to remember stuff these days unless I make a note of it somewhere, so I'll get it right and save it in my notes this time.
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Post by sime66 on Oct 1, 2015 13:30:56 GMT
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Post by pxguru on Oct 1, 2015 16:25:49 GMT
Looks perfect You must be happy about that! 55/160 should do it for starters. That dividing the numbers thing is close but not really the whole story. The small number is for the idle (when idling). This is the correct number when a very stable and slow idle can be achieved and the mixture screw ends up less than 2 turns out. The large number is for pick up from idle and up to 1/8th throttle. The bigger the number the weaker it is. Correct when pick up is crisp and run down (closed throttle) doesn't pop (too weak).
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Post by vespasco on Oct 1, 2015 18:00:56 GMT
Good news! Again.... your head and cylinder looks great. I can see why you wear dark sunglasses now If you want rich when running-in I'd also suggest the 55/160 If its way too rich, (itll be ok im sure) the 52/140 that you've got would be the next one to try. Generally, I look at the smaller number of the idle jet eg, 55 (/160), in a similar way to the main jet number...bigger number = bigger hole = lets more 2T fuel through = richer. Then the larger number i look at in a similar way to the air corrector on the main stack. Same again, larger number = larger hole = more AIR goes to the mix Nows a good time to check your how far your plug protrudes into the chamber, with your CHT sensor ring etc. fitted. If your CHT can use the red Koso cht sensor rings (same as the SIP speedo) then ive a few spare, mostly 14mm for the plug and im sure ive got a few 10mm for cylinder studs. Anyone else?? Price of P&P only. My cht sensor drilled direct into the head is still working perfectly. Its lasted longer than those rings used to thats for sure... Especially when it comes to plug chopping etc.
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Post by henri on Oct 1, 2015 18:25:14 GMT
if ya wanna see pressure testing done by the book , check this ,http://vespasmallframeforum.proboards.com/thread/19440/new-project?page=3 , guys a trained engineer n knows his onions,an other root vegetables , an if bugs bitten hard read the whole thread , tunings addictive eh , an to think about 12 months ago i was thinkin of banning you,sime,from using power tools for ya own safety ,come a long way eh , am quietly (not much,an unusual for me)proud of ya . really enjoying seeing this 1 come to life , H
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Post by vespasco on Oct 1, 2015 18:41:45 GMT
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Post by henri on Oct 1, 2015 18:50:52 GMT
thanks vesp, beyond my IT skills , an my IT specialist is away on summer camp with skool , an i cant afford the chocalate bribes anyway , tzsteves a known guy ,his sh*ts golden , in a way of sayin ,if he's postin its worth readin, for a scouser , am allowed to say that as 1 myself, read the whole thread , its a education , H
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Post by vespasco on Oct 1, 2015 18:58:55 GMT
I will be exploring that some more H dont worry. Interesting stuff Thanks for sharing
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Post by henri on Oct 1, 2015 19:29:17 GMT
theres more ,so much more , careful smallie world beckons , i thought i was strong n cud resist , but life makes fools of prideful men ,youve been warned ,whilst on the subject??? , am hopefully on my way to hartlepool to get a 63 v50n an a 78 primmy ,cheap , will be returning practically past ya door n stoppin in cambridge to see my oppo , go on ,tell me ya aint tempted n i'll call ya a liar . H
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Post by vespasco on Oct 1, 2015 20:14:23 GMT
Well youre more than welcome H, absolutely anytime. Im not sure it'll be on your way home from Hartlepool to yours but if it is please stop by I'm actually about 1hr from Cambridge, towards the east coast. Hhmmm, smallies... Ive had two stock primmy et3 and I always said my most ultra reliable scoot was a v90. I do like them. But i found i much prefer something a bit heavier on fast roads and lighter on the knuckles (when working on them). Im still admiring the cleanliness of that motor and look forward to seeing it covered in road dust, mud, rain, snow, fog, slightly-overcast-but-mild-for-this-time-of-year and of course lots of glorious sunshine
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Post by henri on Oct 1, 2015 20:36:38 GMT
simes is lookin gud eh , an ya forgot sheep sh*t , he lives with the turnip/carrot people , cant wait to see it runnin ,might even be worth a "run to the scum" ,just to hear it in real time , H
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Post by djloone on Oct 1, 2015 20:47:23 GMT
Whereabouts are you vespasco..i reckon we could be fairly close neighbours..you know Kings lynn/Wisbech?..im out that way..free party territory LOON-E
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Post by henri on Oct 1, 2015 20:52:22 GMT
oh sh*t ,another flatlander on the firm , worlds gone to pot/flat . only jokin , ya bogtrottin webtoed utd supported , am sure vesp is a delia/norwich fan , sh*t just got interesting , H
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Post by sime66 on Oct 1, 2015 21:05:00 GMT
Thanks chaps. ......and lots of different snippets of advice and info to cogitate too – nothing will be ignored, but tonight I wanted to get barrel on and torqued, and do some quick dims, just so I can satisfy myself the jobs a good'un, so.................
…..yes it is - - - spot on; well done New-Best-Friend-Lathe-Man!!
(showed the plug, vespasco) (not enough hands/fingers to show measuring DH, but trust me it's good).
That's with my two spacers (2.2mm), so port timings are exactly as intended with those, and I've got my 3mm skim spot on, so squish and volumes won't be far out; I'll check those as first job tomorrow. Then I really want to finish my CHT gauge on the scooter (tank out for wiring), so I can have some temps off that engine on a good, planned ride on Sunday before I think about taking that one out. My CHT will be on a stud, at least for now.
Noted about idle jets, chaps; all sunk in and will order bits in the morning or maybe Monday – I held off today in case I can think of any other bits I need to order. - On that subject, I spent some time going through Wasp site last night, and ordered loads of little bits quite late evening, and it's all dispatched today, 1st class, due tomorrow – well done Wasp.
That pressure test stuff is excellent, H; thanks. And that thread is a bit special too; I've bookmarked it and will have a good read during the long Winter nights – not now though, got loads to do now before Winter..........................
I didn't want to get too excited too early this afternoon, but now after a quick check I'm happy! Might have an extra orange juice.....
…....and what do you know about Run from the Scum!!!!!! - Dodgy bunch; Troglodytes - I'll post the info for next year when it comes out - will be about the weekend of my 50th.
Loon-e I looked your location up earlier and noticed you weren't so far from vespasco – I can feel something messy creeping up!
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Post by sime66 on Oct 2, 2015 9:47:45 GMT
I might as well keep this going here. This morning I've checked my squish and volumes, and rechecked my compression ratio calcs with new numbers; comparing calculated against measured after skim. I think they make pretty good reading; you have to recall previous discussion concerning causes for errors in the measuring methods I'm using; it's not a lab, it's my desk and workbench and some cheap kit, so the volume measures particularly are really a double-check of calcs from measuring, which are accurate. In any case the discrepancy is slight, and the slight difference is an improvement, so the calcs show good ratios and the measures shows slightly better: Calculated:CR = 10.24:1 CCR = 6.56:1 Measured:CR = 10.35:1 CCR = 6.6:1 Previous Calcs, overmarked with new measure (pink/yellow highlighter):
Volume Measure:
Squish Measure (good – as expected):
I'll be guided by you clever chaps if you think it needs any checking or tweaking, but when you consider the slight discrepancy against the potential inaccuracies in measurement, the difference must be within those tolerances, in which case I'm leaning towards leaving well alone, bolting it up and buying petrol................................
If so, I'll retorque the whole job, put my rings in, bolt barrel and head down with sealant, and give it the pressure test. I won't do the presure test until everything else is satisfied though, and I'll leave this for a few replies; I'm thinking now about making some stud sleeves to centre the head a bit more precisely. There's also a lot of stuff posted lastnight that I need to read through properly; I was doing my engine whilst you lot were planning a party!!!!
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Post by djloone on Oct 2, 2015 14:03:11 GMT
I salute you Si, you really are going for a perfect motor...sh*t i,ll be happy if mine runs..think im gonna stay stuck in the 80s when it comes to engine/electric/body work..chuck it on..kick it over..and pray ya start..run..get there..and make it home LOON-E
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Post by henri on Oct 2, 2015 14:13:28 GMT
yep , bolt it up n pressure test , to be sure .tho i'd probably bolt up n throw in scoot an let the seat of my pants make a judgement on it , H
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Post by vespasco on Oct 2, 2015 16:01:50 GMT
Those figures still look pretty darn good to me. Id leave it and bolt it together etc. I didnt check your figures just yet but im sure i dont need to. I'd be well chuffed.
Hey loone... I was riding around kings lynn a few weeks ago (again, about 1hr from me)! Had quite a few twist n go-ers pulling up at traffic lights expecting to beat me off the line. They had no chance. Although it wasnt easy keeping my front wheel on the ground
And i know too well there are some good free parties out that way (and all over the Norfolk countryside) Or there certainly used to be. I used to go to loads in the mid/late 90s. Im not sure i ever recovered! I do remember the Littleport parties.
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Post by pxguru on Oct 3, 2015 5:27:22 GMT
Calcs all work out fine. As you have everything there you could do the volume check with the head on and rings in. Use a heavy oil. At TDC fill it to the botton of the plug hole. A bit messy but a valid check. The dome volume is usually the dodgy one. Most piston domes are not a single profile and the numbers go down! Sleeves to centre the head are a good idea. Off centre heads cause detonation and we dont want any of that! 2 sleeves diagonally opposite are plenty. These are the 200 ones from SIP. Your lathe man friend could easy make some. And way quicker that SIP delivery too! www.sip-scootershop.com/en/products/centring+bushes+cylinder+head+_m2615774Have you reviewed the porting degrees in the same way? Just for the record at this stage of the build, what do you think will do on Microdyno?
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Post by sime66 on Oct 3, 2015 6:23:15 GMT
Thanks everyone; I was just doing a quick general reply, waiting for it to get light so I can crack-on with scooter jobs outside when your post popped up, pxguru, so I'll do that too. I did do a volume check with head on at TDC, not with rings, but with grease around dome and the same 2 stoke oil. It did come out slightly lower, but I put that down to the grease and possibly air trapped inside the head, though I did use a level to try to get the plug hole top and level. Actually the DH volume is 2.65 and the dome volume (as a simple arc) calculates at 2.73, so they should have cancelled each other out anyway, and the volume should have been the same, but it was more like 18.75, but I dismissed it as being less accurate, or within tolerances of my method and equipment. If you think that measure difference is significant, I will recheck more carefully, but I thought I was OK. I have time to do it because I want to paint the barrel before final torquing down and pressure test; maybe I'll put the rings on and repeat it. It's simple enough to take a bit out of the dome if we're getting close to concern and a bit more volume would ease the doubt. My port timing degrees are identical to previous check – unchanged with the 2.2mm spacer and gasket; skimming didn't change that – DH has changed, but TDC to port dims haven't. I have considered that a bit of sealant might raise the timing a smidge, and also increase the chamber volume ever so slightly, which was another reason I left that volume measure there. I made some sleeves out of a sardine tin – do you think this is taking bodgery too far? - it's vespasco's fault; he used an old pen! - I had intended to find something more suitable – a bit of tube if I can find right ID and OD – but my lunch yesterday gave me inspiration to try making these little beauties:
I have no idea what Microdyno might give us; I think I recall you saying around 15, which sort of stuck in my mind, but I really don't know. For me it'll be how it pulls me up the hills round here that I'll hope to notice some more power. My timings are for max power at 7500rpm, and my gearing puts that at 71mph:
It's not too late to check anything where there's doubts; I don't need to rush – this bit did go quicker and smoother than expected because the numbers came out so close to what was intended (because he did exactly what I asked), but time isn't as important as getting it right – I'd kinda quite like to stop spending now though!!
(just bought me shocks - (Carbone), and already budgeted next month's spare cash on rims and tyres)
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Post by pxguru on Oct 3, 2015 7:24:02 GMT
Once run in this will make easy 15bhp. I can't believe it won't do over GPS 70mph either!
I'd like a re-run of the port measurements all done fresh, just to be sure. transfer to deck exhaust to deck boost to deck This is the important bit, as it is where most of the power comes from!
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