Fitting A Piston?

Discussion in 'The Workshop' started by Hursty, Nov 22, 2007.

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  1. Hursty

    Hursty New Member

    Messages:
    806
    im fine with top ends ive watched alot of people do them.. just wanna clear a couple things up

    the arrow faces on the piston faces the exhaust port rite ?

    how do i get the gudgeon pin clips in ?

    and best way to get the piston into the cyclinder?

    infact.. a clear up of how to fit the piston from the start lol

    any help is apreciated

    cheers

    ben.
     
    Hursty, Nov 22, 2007
    #1
  2. xenovia

    xenovia New Member

    Messages:
    220
    For the circlips, I used needle nose pliers to grip the clips, then put them in at an angle. Then I used a screwdriver (carefully) to push them the rest of the way in until they clicked.

    For getting the piston into the cylinder, I just gripped the piston rings until they were flush with the surface of the piston, and slid it in (making sure the gaps in the rings line up with the pips).

    And yes, the arrow does point down, and the port to the top.
     
    xenovia, Nov 23, 2007
    #2
  3. monty9120

    monty9120 Active Member

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    i always put one edge of the circlip into the groove then use a flat screwdriver gently to prise them in

    make sure you put something like a rag over the hole though if the circlip comes pinging out (happens alot) and it goes in the crankcase there will be trouble

    piston. make sure the rings have oil. do one ring at a time make sure there butted up properly as they will compress over the peg. be careful dont rush if its not done right it shouldnt go on simple as so not really a hard job at all

    you can put one circlip on the piston with it off. the side you cant get too well which is handy
     
    monty9120, Nov 23, 2007
    #3
  4. Hursty

    Hursty New Member

    Messages:
    806
    rite.. the circlips are the ones like.. well they are nearly a circle but with a bit taken out.. or the round clips with a bit comin off ?
     
    Hursty, Nov 23, 2007
    #4
  5. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

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    i pout em in by hand in most cases.. just put the gap towards the hole laterally and push, as it squeezes together let it fall to the right or left and it will pop into place.

    rings the best way is put them on the piston then push them flat with your thumb on the exhaust side.. then make the gap on the pegs even and only then compress them all together.. if done right 3 fingers will hold it all in place.

    use shit oil for build lubrication, excess synthetic oil will churn to mayonaise with the ammounts you need to use. thin mineral oils let the parts wear quicker and doesent go stiff when agitated.
     
    MiNoR cOnFuSiOn, Nov 23, 2007
    #5
  6. wobbly_trials

    wobbly_trials Active Member

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    what ring gap should there be on a 70? bloody malossi kits are never gapped right. Sory to hi-jack the thread, its kind of on the same topic
     
    wobbly_trials, Nov 23, 2007
    #6
  7. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

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    depends on na few things like piston, ring and bore material. but minimum of .28 and max of around .71 i usually go to..depends on application too. should be in the literature that comes with the kit tho. there always too tight.

    some kits ive had to move the peg insert inwards... probably the wrong rings but they worked fine.
     
    MiNoR cOnFuSiOn, Nov 23, 2007
    #7
  8. wobbly_trials

    wobbly_trials Active Member

    Messages:
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    its a malossi iron kit after honing it was reading 5 thou so i left it at that.
     
    wobbly_trials, Nov 23, 2007
    #8
  9. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

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    dont be so cheap.. get yourself some METRIC fela guages :D
     
    MiNoR cOnFuSiOn, Nov 23, 2007
    #9
  10. wobbly_trials

    wobbly_trials Active Member

    Messages:
    6,676
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    imperial FTW, i prefer to work in thou. it sounds far more sophisticated.
     
    wobbly_trials, Nov 23, 2007
    #10
  11. Hursty

    Hursty New Member

    Messages:
    806
    done the whole top end myself for the first time!! what a peice of piss :D

    ben.
     
    Hursty, Nov 23, 2007
    #11
  12. wobbly_trials

    wobbly_trials Active Member

    Messages:
    6,676
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    RD350, SR125, ICE125
    what torque have you taken the head down to?
     
    wobbly_trials, Nov 23, 2007
    #12
  13. Hursty

    Hursty New Member

    Messages:
    806
    havent bolted the head down yet.. just on loose what should they be ?
     
    Hursty, Nov 23, 2007
    #13
  14. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

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    12-15 they sudgest on 10mm threads. i smack em up to a gentle 20 tho..

    and thou just makes you sound 60 not sophisticated :D
     
    MiNoR cOnFuSiOn, Nov 23, 2007
    #14
  15. wobbly_trials

    wobbly_trials Active Member

    Messages:
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    would that be ft/;bs minor?

    and thou is sooo much easier (for me working on a land-rover anyway), although nothing is that close tolerances, more like feet, thats just the plug gap.
     
    wobbly_trials, Nov 23, 2007
    #15
  16. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

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    well, that, yopur valve clearances and youre dire old piont's and condencor dizzy setup (unless you fitted a decent luminition kit)
     
    MiNoR cOnFuSiOn, Nov 23, 2007
    #16
  17. wobbly_trials

    wobbly_trials Active Member

    Messages:
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    Rides:
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    nope stuck to the dizzy but fitted an early Mini one to make the motor a little more revvy.
     
    wobbly_trials, Nov 23, 2007
    #17
  18. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
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    lucas 45 or the old shitty one?
     
    MiNoR cOnFuSiOn, Nov 23, 2007
    #18
  19. wobbly_trials

    wobbly_trials Active Member

    Messages:
    6,676
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    think its a lucas one, it's one my step-dad had from yonks ago.
     
    wobbly_trials, Nov 23, 2007
    #19
  20. Hursty

    Hursty New Member

    Messages:
    806
    whats that in nm ?

    ben.
     
    Hursty, Nov 24, 2007
    #20
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