Needles in the place of the bearing.

Discussion in '2-Stroke Engines' started by FelipeCobu, Sep 9, 2011.

  1. FelipeCobu

    FelipeCobu Member

    This morning I went to a machine shop to have my crank disassembled, since I got an engine lock due bearing fail I will change all bearing and will have my crank aligned and balanced too. When I machinist come to me with my crank in two parts we saw that instead off a cage bearing (at the big end off the rod) it haves only needles - 23 off them to be exactly, although the rod pin diameter is 6mm and the big bore 21mm so I will replace it for a INA kzk 16x21x10 bearing that I found here.

    Felipe Cobu
     

  2. motorpsycho

    motorpsycho Active Member

    needle bearings are actually better than cage bearings.
     
  3. HeadSmess

    HeadSmess Well-Known Member

    NIGHTMARE TO STICK EM IN BUT IF YOU CAN GO FOR IT.

    stupid caps lock!
     
  4. Paratrooper

    Paratrooper New Member

    A TON of gooey 90wt grease will make it stay together a lot easier until you get it together.
     
  5. Big Red

    Big Red Active Member

    90 weight?

    Don't think I would recomend using 90 weight wheel bearing grease to hold in the needle bearings. First, It was not made for "high speed bearings" A wheel bearing does not turn at six to eight thousand RPM. Also, that heavy a grease will apply added pressure to the bearings untill it "washes out" with the 2 cycle mix. Putting in bearings can sometimes be a real pain in the a$$, but the only thing you really should use is a good 2 stroke oil as a pre-lube. I can't count how many top ends I've rebuilt and I've never used anything else.
    Big Red.
     
  6. FelipeCobu

    FelipeCobu Member

    So you guys think I should keep the needles on instead of change it to cage bearing?

    Thanks a lot.

    Felipe
     
  7. Big Red

    Big Red Active Member

    Bearings

    Needle bearings are better simply because there is more support between the crank end and the wristpin then the cage bearings give. You use more "needles" then what are in the cage bearing so it has more to "lean on" so to speak. Plus more bearings to take the total wear so they are supposed to last longer. I've never had problems with either one. If you're trying to build a high performance engine, go with the needle bearings. Otherwise, It's just easier to install the cage bearings.
     
  8. FelipeCobu

    FelipeCobu Member

    Big Red,

    Thank you for the reply. Will keep the needles in their place.

    Just to leave it registered the needles dimensions are 2.5mm x 10mm for
    those who can't thrust the OEM China bearing, and are having bad times
    trying to found quality K16x21x10 needle cage. And 23 needle rollers are needed.

    I don't used a bore gauge nor a micrometer to but perhaps it may need some reaming in order to use the rollers instead the cage bearing.

    Felipe Cobu
     
  9. Big Red

    Big Red Active Member

    Then have a machine shop do it.
    Big Red.
     
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