SX3’s Ciao perso [English]

Home Forums Perso’s Projecten SX3’s Ciao perso [English]

Dit onderwerp bevat 210 reacties, heeft 27 stemmen, en is het laatst gewijzigd door Seru.ch 3 dagen, 23 uur geleden.

15 berichten aan het bekijken - 196 tot 210 (van in totaal 211)
  • Gebruiker
  • #788361

    sx3-swe
    Topic starter
    Berichten: 239

    Sucess!! The kop fits like a glove and centres perfectly. 🙂
    Even though my caluculations wasn’t 100% I’m still in the ball park!
    I only measured a 46mm Polini head gasket, and it was 0,5mm, I have ordered 43mm gasket and only assumed it would be 0,5mm aswell. Perhaps it’s a bit thinner? Or soft meterial that reduces 0,1 or something:)

    When you guys reflect over the below scenarios, have in mind:
    – DR 43, 13mm, Proma CC, Vario

    Scenario A:
    Head gasket: —
    Base gasket: 0,5mm
    Squish: 0,6mm
    Conclusion: Too low

    Scenario B:
    Head gasket: 0,5mm
    Base gasket: 0,5mm
    Squish: 1,1mm
    Conclusion: A little bit in the higher regions, I was aiming at 1,00 to have some marigins to 0,8 which would be a sweet spot.

    Scenario C:
    Head gasket: 0,5mm
    Base gasket: 0,3mm
    Squish: 0,9mm
    Conclusion: This would be a sweet spot!.

    Scenario D:
    Head gasket: —
    Base gasket: 0,8mm
    Squish: 0,9mm
    Conclusion: This would be a sweet spot! Also the head would be steering 0,7mm inside the cylinder, better durability I think.

    It isn’t all about squish, as @martino said, the port timining will be affected in a small manner when playing with base gasket.. I know too littlle about 2-stroke tuning to know which scenario would be the best. Maybe you guys can help me out choosing? 😀

    I want a strong machine, rather than fast machine.

    @Herr Flick, I can only agree with you. I haven’t been happy with any Polini-Ciao parts lately.
    Carter, kop and vorvario.. The don’t put any love into the production. I can only hope for their own sake that they do better scooter parts.

    • Deze reactie is gewijzigd 1 week, 2 dagen geleden door sx3-swe.
    #788366

    zevenenergie
    Forum Goeroe
    Berichten: 2497

    I think you will benefit frome a hotter port timing.
    So I whould go for for scenario C, whit the 0,8mm base gasket. 😛

    And compliments for the awsome work and thanks for the video,s :thumbs

    • Deze reactie is gewijzigd 1 week, 2 dagen geleden door zevenenergie.
    Draaiwerk, freeswerk, carters kotteren? Reparatie of tuning?
    Klik hier.
    #788370

    Crullie
    Donateur
    Berichten: 1706

    Scenario D+:
    Always a fan for thicker base Gaskets :thumb
    More feeding time means also higher compression so the squish at 1.0mm to 1.2mm for a more comfortable ride and more reliability.
    Succes, always a pleasure to see your work  😛

    TICKLING BARN
    #788402

    sx3-swe
    Topic starter
    Berichten: 239

    Thanks guys!
    I got the head gasket today, it was 0,4mm full-aluminium gasket (not alu-coated copper-gasket).
    So tried out with this gasket + 0,5mm cylinder gasket, giving me 1mm squish.

    Experience:
    1. Compression is high (haven’t measured it, but it much higher than before, thats for sure!
    2. vibrations, vibrations vibrations.. They have escalated since last run. It’s really not nice to hold the handles at full throttle. After a while I can’t feel them 😀
    3. When I rev up and let go, it returns to Idle but in some occasions it could take 1-2 seconds for the idle to settle down.. I think you can hear it in the video below.
    4. the head seem to leak a little bit, I think it’s because of the stiffer-type aluminium head gasket (same type as cylinder base gasket that are rubbish.
    5. The bolt that holds the Proma in the cylinder head, wasn’t included.. Cheap bastards!! (the silencer is F****ng joke, not just the sound, but also finnish looks garbage)

    Unfortunatly, I have made some other changes too, since last run.. Variator,  pinasco flywheel, proma CC are installed so I can’t really tell what causes my experience.

    1/2: So the question is, is the low squish/high compression one reason for vibrations?
    @crullie, you said 1-1,2mm squish for a comfortable ride, is that because of vibrations or something else?

    3. Leaking? The cylinder head?

    4: Hmm, I think the gasket is to stiff.. the alu-coated copper gasket was coming from a 46mm polini gasket kit.. I wonder if Athena och Malossi gasket kit for 43mm will give the softer gasket or the stiffer one..
    Am I correct that Liquid gasket isn’t good for this aplication?

    4. Almost dropped the exhaust, gotta get that bolt 😀

    (The rattling sound in video is the Vario belt slamming against the frame.)

    So, when I noticed that I’m almost dropped the exhaust, I had to bicycle home.

    And a small treat for every one who have read above 😀 As you can see, the machine ain’t fixed, as one “ear” have been chopped off 🙁 Hopefully this is only cosmetic and the part will be useble anyway!

    Resized_20190707_205759

    • Deze reactie is gewijzigd 1 week, 1 dag geleden door sx3-swe.
    #788440

    zevenenergie
    Forum Goeroe
    Berichten: 2497

    Quote
    @crullie, you said 1-1,2mm squish for a comfortable ride, is that because of vibrations or something else?

    When the compresion ratio is high, a two stroke engine tends to runs a bit raw or nervous.
    I kind of like it 😎
    But it has noting to do whit vibrations, Like you can feel in your stearing handels or saddle.

    Making a squihs lager then 1mm is a foulisch action, because the whole idea is to cool off the gasses in the squihs band. And that doesn’t happen from 1mm and up.
    The result can be detonation. And that may well be the case. But I don’t know what your compression ratio is.

    You can still try to make the squihs 0.6 mm.
    A Dr43 doesn’t make a lot of revs so I don’t think your piston will hit the head.

    At 0.6 mm your compression will be a little higher, but the smaller squihs space will prevent detonation.
    Detonation makes a  ringing metal sound. like as if there is a marble in your combusting chamber.

    I don’t know what causes the vibrations. Maybe the pinasco?

    • Deze reactie is gewijzigd 1 week geleden door zevenenergie.
    Draaiwerk, freeswerk, carters kotteren? Reparatie of tuning?
    Klik hier.
    #788466

    sx3-swe
    Topic starter
    Berichten: 239

    Hmm, I don’t think I have detonations.. Haven’t heard them atleast but I might not be able to tell the difference.

    My compression is almost 12,5 Kg/cm² (measured with open throttle, and using the pedals like a tour the france race)

    Edit: I took the flywheel off and grinded it a bit like @jelle needed to do, the key wasn’t riding smooth. However it didn’t help..
    Another thought is that I haven’t fastened the Proma on the cylinder head, perhaps it’s causing resonans and vibrations because of this..

    IMG_20190709_120621

    • Deze reactie is gewijzigd 6 dagen, 22 uur geleden door sx3-swe.
    #788481

    ArvidW
    Donateur
    Berichten: 6243

    In this topic Zevenenergie discusses his cilinderhead. If I’m correct he’s talking about 1:11 to 1:13.5 uncorrected compression ratio. This is the theoretical value that doesn’t take into account the exhaust port being open for a substantial part of the compression stroke.

    Your measured value of 1:12.5 sounds very high to me. A quick google search mainly shows 250cc road racers / high end dirt bike running a measured >1:12 compression ratio.

    AW50-4t | 13.13 | Gianelli Citypower | 3.2Nm@5800rpm | 2.8pk@6500rpm
    Home made engine dyno
    #788483

    sx3-swe
    Topic starter
    Berichten: 239

    Thanks for the Input Arvid, I have read that thread  a couple of times and I have misunderstood Zevens question. my 12,5kg/cm² is just the compression.. (showing no leakage in rings, gaskets and so) It isn’t the compression ratio that is relevent to the question. 🙂 So I make, what we call in sweden “a poodle” in this manner.

    I have read and understood the formula for CR in squish-thread, and I will hopefully tomorow measure it with the engine oil method. I will report back what my CR is.. But I wouldn’t suprised if my CR is in the upper level with the HD-kop + squishband starts inside the cylinder.

    #788488

    ArvidW
    Donateur
    Berichten: 6243

    I’m very interrested to see the result of your CR measurement. It’s most likely way higher than the compression you’ve measured.

    AW50-4t | 13.13 | Gianelli Citypower | 3.2Nm@5800rpm | 2.8pk@6500rpm
    Home made engine dyno
    #788501

    sx3-swe
    Topic starter
    Berichten: 239

    Okey, I managed to measure the CCV.. The test isn’t the most scientific but I did my best.
    It was hard to tell when I had reached the threads for sparkplug but something around 5,4ml oil, perhaps 5,3 was the limit but I missed it.

    If I’m not incorrect, the compression ratio would be 12,56 (5,4ml) and 12,77 (5,3ml)

     

    CR

    So what can we conclude from this? I would need 102 octane race fuel for my daily driver to not have detonations? 😀

    Getting theese values I have used a 0,5mm cylinder base gasket and 0,4mm cylinder head gasket.
    The squish is 1.0mm sharp.

    • Deze reactie is gewijzigd 5 dagen, 21 uur geleden door sx3-swe.
    #788505

    Seru.ch
    Bijdrager
    Berichten: 23

    All your values sounds perfect (squish, Compresion ratio).
    When you have detonations, you can see sperical (half round) holes at the borders of the piston and head. The heavy vibrations coms from a other part. Do you have a original Flywheel to test it?

    #788543

    sx3-swe
    Topic starter
    Berichten: 239

    I guess they are Okey, but not perfect. 🙂

    0,6 in Squish will give 1:14,00 compression ratio
    0,8 in Squish will give 1:13,23 compression ratio

    The Malossi DEPS-2 have 1:13,5 something..
    But it all depends on how I elaborate with gasket thinknesses, in some cases the cylinder rises, which will give other positive effects on port timings.

    Using 0,8 base gasket and no head gasket would gick 0,9mm in squish and 1:12,88 CR
    Using 0,3 base gasket and 0,4 head gasket would give 0,8 in squish and 1:13,23 CR.
    Usen 0,5 base gasket, no head gasket would give 0,6 in squish and 1:14.00 CR

    • Deze reactie is gewijzigd 4 dagen, 3 uur geleden door sx3-swe.
    #788546

    Seru.ch
    Bijdrager
    Berichten: 23

    My Opinion: Take the 0.5mm basegasket and no headgasket (squish 0.6mm) and then making the combustionchamber biger so you reach a compression ratio of ca. 12.5:1.

    And mashining my head to so nicely like yours. 🙂

    #788547

    Seru.ch
    Bijdrager
    Berichten: 23

    My Opinion: Take the 0.5mm basegasket and no headgasket (squish 0.6mm) and then making the combustionchamber biger so you reach a compression ratio of ca. 12.5:1.

    And mashining my head to so nicely like yours.

    #788549

    sx3-swe
    Topic starter
    Berichten: 239

    Designing a combustion chamber is far out of my knowledge and is a science of its own. I would need remove 0,6ml of volume and I’m not sure how much material there is to work with inside of there.

    • Deze reactie is gewijzigd 4 dagen geleden door sx3-swe.
15 berichten aan het bekijken - 196 tot 210 (van in totaal 211)

Je moet ingelogd zijn om een reactie op dit onderwerp te kunnen geven.