How to replace crank?

Discussion in 'Newbie Scooter Tuning' started by Joe.write, Feb 19, 2020.

  1. Joe.write

    Joe.write New Member

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    18
    I have a piaggio zip 50 2t here and have bought a 70kit and a new crank for it (along with all other stuff like carb etc) and I’m very confused, I’ve never done anything regarding scooter tuning and didn’t realise how hard this would be, has anyone got any guides or videos that would help me as I can’t seem to find any, or (if I’m allowed to post location on here) would any kind person want to come help me out? I could throw a bit of cash your way but not loads as I spent it all on parts haha
     
  2. MARSH

    MARSH Whooooo!

    Messages:
    3,020
    Rides:
    Piaggio Typhoon
    Try a scooter repair shop, they will be able to help you.
     
  3. Joe.write

    Joe.write New Member

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    I have been considering this however there are not many near me and wouldn’t it end up costing me something like £300 lol
     
  4. scubabiker

    scubabiker NITROJUNKIE

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    7,321
    Pretty sure there are some on YouTube.
     
  5. Joe.write

    Joe.write New Member

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    18
    There are a couple but none are really very good or in depth, I’ve yet to find one that also shows the process of taking the engine apart, most just show a vauge description of how to put the crank on with some annoying music and text lol
     
  6. scubabiker

    scubabiker NITROJUNKIE

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    7,321
    Try carlsalter.com and have a check for a manual there.
    The Honda common workshop manual is on that site which is a goldmine of how to tips.
     
  7. MARSH

    MARSH Whooooo!

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    3,020
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    I don't want to pee on your fire but if you don't have the knowledge or have the necessary tools, then you could end up making more of a problem !
     
    Mark Emerson Trentham likes this.
  8. Joe.write

    Joe.write New Member

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    Yeah exactly that’s why I’m not sure if I want to proceed,especially with no help
     
  9. Rickard Pingol

    Rickard Pingol Active Member

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    Ive done it. Its not that hard." And i did it when there was no youtube or other help but hearsay from people who supposedly knew" But it takes some work and disassembly. And off course you need proper tools. Theres loads of videos out there. Try the one that you like. When invited my girlfriend for the first time m to my home. She had a little shock. When i had the whole engine on the living table :).
    Just search: change scooter crankshaft on yt.
    But theres a few no no's. Like dont ever drop you crank. Can get out of balance. And its better to pull the crank in place with a proper tool than. In worst case having to slam it in place a bit with a hammer. Just ask us if there some particular part you are unsure about
     
  10. Joe.write

    Joe.write New Member

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    18
    Thank you mate i will definitely ask if I need it, I’m going to give this a go at the weekend, I’ve seen on some videos that they put the crank in the freezer and the bearings in the oven (or vice versa I’m not sure) is this nessecary as I have some polymer bearings
     
  11. milo2025

    milo2025 Trip to Trumpton

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    Whichever it is you want to get it the right way round! :p At a guess it would be the crank in the oven and the bearings in the freezer but please don't quote me on that or take my word for it - I still value my life. :)
     
    Last edited: Feb 19, 2020
  12. Rickard Pingol

    Rickard Pingol Active Member

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    205
    Most vids gives a great tutorials on the subject. Just go ahead and do it and reach level 2 in scooter mechanics :).
    I dont know it is for somebodys interest. But mine failed. Because of faulty casting. The holes that allow some of the gas/oil mixture to pass through the bearings. Was gloggged because of the casting, so it didnt get proper lubrication. The bearing failed, and the crank axle on the variator side started to wobnle slightly. So that it destroyed the sealing. Leading to loss in compression in crankcase. And scooter didnt want to run
     
    Last edited: Feb 19, 2020
    milo2025 likes this.
  13. scubabiker

    scubabiker NITROJUNKIE

    Messages:
    7,321
    I would advise getting a heat gun, it's a useful tool to have and pretty much the only "special" tool you will need
     
  14. Joe.write

    Joe.write New Member

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    Hahaha definitely, I’ll watch one of the vids over and make sure when I do it
     
  15. Joe.write

    Joe.write New Member

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    18
    I’ll have a look and see if I can find a fairly cheap one on eBay, if not I’ll use my mums hairdryer :D :confused:
     
  16. Joe.write

    Joe.write New Member

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    18
    Did it break any parts when this happened? Or was it just a case of putting it back together?
     
  17. milo2025

    milo2025 Trip to Trumpton

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    727
    LOL
     
  18. MARSH

    MARSH Whooooo!

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    3,020
    Rides:
    Piaggio Typhoon
    If you intend to do it then we'll try to help. As said tools needed- heat gun, copper mallet, hammer, torque wrench, socket set, spanners.
    Once engine is stripped, give it a good clean inside and out. This is how I do it!
    1. Put the crank in the freezer for 24 hours.
    2. Freeze main bearings for a couple of hours.
    3. Test fit cases so they fall together, clean up locating dowls so cases go together/ apart easy, real easy.
    4. Get both sides of the cases hot using heat gun, usually until they smoke a little (not melting !)
    5. Fit bearings quickly to cases using a small hammer, tapping round bearing outer NOT INNER RACE, you'll hear them change sound when bottomed down.
    6. Liquid gasket sealer on mating faces of cases.
    7. Heat both bearings gently round n round.
    8. Get your casing bolts ready, cleaned threads and copper slipped ends.
    9. While heating bearings, get someone to get the crank out the freezer (wife in my case).
    10. Quickly fit crank to flywheel side case, you should hear crank bottom out in bearings, hold crank in tightly so it don't fall out then fit to main case, it should butt up straight in first go.
    11. Fit casing bolts, but don't use them to pull cases together, they should have gone together up tight.
    12. Torque casing bolts to 10Nm ? being 6 mm. The crank should spin freely, leave for a while to warm through, fit crank seals.
    This works for me, others may say different. See how you get on.
     
    Rickard Pingol likes this.
  19. Rickard Pingol

    Rickard Pingol Active Member

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    205
    The bearing seat on the crank was destroyed. I had ridden a while like this. And the Bearing. And seal was replaced
     
  20. milo2025

    milo2025 Trip to Trumpton

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    727
    Whoops I got that wrong.
     
    Last edited: Feb 19, 2020
    Rickard Pingol likes this.

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