Hole in the middle of the Crank...

Discussion in 'Motorized Bicycle General Discussion' started by jonvb69, Aug 1, 2011.

  1. jonvb69

    jonvb69 New Member

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    Hey, just a quick question just to make sure I'm doing things right. I took apart my motor realized the piston was smacking my head of my motor which is odd but it was happening... might have tightened the head to much? Anyways ill get that taken care of i believe its 10-12ft pounds of torque to put it down. My crank though I took the casing off to get the chain off to remove my motor completely from my bike and when I tipped my motor a little bit and noticed a bearing and cyclinder looking thing fall out of the hole in the middle of the crank. Is there only one bearing and that cyclinder or two bearings? I was thinking maybe one rolled away. I just wanted to double check b.c. I know everything needs to be perfect. Which order do I put them back in? Ball Bearing then cyclinder?
     
  2. DaveC

    DaveC Member

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    Yes, ball bearing then bucking bar and grease them with the thickest grease you can find, like suspension grease. Assembly grease and Lubriplate aren't really thick enough but will do in a pinch. This assembly is under constant pressure and always turns when the motor is running..

    About the piston slapping the head. That can happen with uneven torques on the head studs. If you have acorn nuts throw them away and get some good nuts from ACE or Lowes or best is a speciality nut and bolt house like I luckly have right down the street. Run your torque to spec in stages using a pattern of some kind like an "X" or "Z". I use a "Z" pattern and after each round of four nuts tightened shift the pattern around 1 place and go to the next torque. I bought my beam-type torque wrench years ago at a used tool place. Now you can get the click-type at Harbor freight for under $15 for a 1/4" wrench. The 3/8ths one is too inacurate in the lowest settings so I'd avoid that one.
     
    #2 DaveC, Aug 1, 2011
    Last edited: Aug 1, 2011
  3. jonvb69

    jonvb69 New Member

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    Alrighty thanks for the info bud much appreciated : )
     
  4. rustycase

    rustycase Gutter Rider

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    Can I sneak in my 2cents?

    Is it possible this engine has a lot of hours on it and wear to the extreme and the crank is throwing the piston too high causing it to hit the head?
    Wore out bearing could do this in an engine that already had a close clearance???

    Perhaps a thicker base or head gasket???
    rc


    DaveC... I just found my old inch/lb snap-on the other day... no clue on it's state of calibration, but it's got a 1/2" drive! lol
     
  5. Al.Fisherman

    Al.Fisherman New Member

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    First I'd mill the head. Then put two gaskets on and torque the head down to 100 inch pounds. Check to see if the piston is still hitting the head. If so repeat with another gasket. Once everything has the clearance, remove the head gaskets, spray both sides of each gasket with Copper Kote or something like it. Replace the head and torque to 150 inch pounds.
     
  6. MarkSumpter

    MarkSumpter New Member

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    Actually my GT5 has thrown the piston way high since the day I got it and the piston smacks the head. I use 2 .020 home made cylinder base gaskets and 2 head gaskets and it runs great. The best way to grease the buck bar and the rest of the clutch shaft is to remove the clutch cable post and insert a m10x1 45 degree angle grease zerk in its place and remove the clutch ring assembly and pump in grease till it just comes out of the bearing on the clutch side. I use a right angle clutch pull and have no use to reinstall the clutch cable post so I leave the zerk in place.
     
  7. Al.Fisherman

    Al.Fisherman New Member

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    Mark...Good idea. I installed my clutch roller and the post is of no use to me. I have to remove the post to lube. At the moment I use a CV joint boot needle. I'll have to look out for a 10mm zerk fitting....Thanks
    Roin
     
  8. dmb

    dmb Active Member

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    rustycase; inch pound 1/2 inch drive,were you a diesel mechanic? used them to set injectors on cummin's engines
     
  9. rustycase

    rustycase Gutter Rider

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    @ dmb

    Wow, you're good!

    Yup, worked on the dump trucks, way back when... then I drove 'em roundy round for a few years, before I started draggin around oilpatch freight... I wasn't tough enough for that... laid me up for a few years. :-(

    ...love the smell of diesel in the morning... :)
    it feels like, well, a paycheck!
    rc
     

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