Home Forums 2-Cycle Racing BEARING COLLAPSE

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    • #21984
      Jim Silverheels
      Participant

      Anyone having trouble with the crank bearings on their Leopards losing the plastic ball bearing spacer? This has just happened again to me. It has happened 3 times in the last 50 engines I have done. The cranks are dead nuts on run out. The bearings come from a reliable vender also. I do place the balls facing in and the spacer facing outward. Any clues appreciated. thanks, chi wa wa

    • #21992
      Glenn L Riggs
      Participant

      I had a batch of fag 6205 shifter bearings that would fail the same way. They are good bearings but made in different countries forgot which country I had the problem ones. Maybe this might help. also have to watch endplay if slightly tight heats up and melts the plastic part. Hope this may help

    • #22024
      Walt Gifford
      Participant

      Go to full compliment.

      Gif

      FAA certified jet engine and aircraft technician,
      Nicholson Speedway class champion 2001,
      Yamaha KT100 Service Center,
      41 years karting experience

    • #22030
      Jim Silverheels
      Participant

      Giff, where do I buy them please? Full comp means more rollers? not really up on that term, thanks

      • #22209
        Jim Gerard
        Participant

        I would be interested in trading some parts for dyno time if your interested.

    • #22218
      Walt Gifford
      Participant

      It’s like all star wrestling all balls no cage. lol, I think you have to make them, that’s what I did.

      Gif

      FAA certified jet engine and aircraft technician,
      Nicholson Speedway class champion 2001,
      Yamaha KT100 Service Center,
      41 years karting experience

    • #22235
      Jim Silverheels
      Participant

      Giff, I did check this out  with my guru from Plattsburgh Ny and he made a point. Take the cage out and add balls would make more friction with ball rubbing on ball. Now that’s a ball of a deal like Mr Gerard  wants, sure Sunday will be fine but early. Daytona comes on at 1pm.

    • #22239
      Walt Gifford
      Participant

      Your guru needs more meditation. The balls rotate in their own spaces. If you’ve blown 50 engines I’d try something different.

      Gif

      FAA certified jet engine and aircraft technician,
      Nicholson Speedway class champion 2001,
      Yamaha KT100 Service Center,
      41 years karting experience

    • #22241
      Jim Russell, Jr
      Participant

      Check your seals. Leaking seals can cause loss of lubrication and hot spots. Then the bearing fails.

      Otherwise it could be a bad batch of separator material.

      We have had the best luck with the SKF bearings.

      Jim jr.

    • #22247
      Jim Silverheels
      Participant

      Giff, with no cage your saying they don’t touch?  c’mon

      Mr Russell, the seals were new, the axial clearance was .012,balls inward, and crank dead nuts. thanks for the input

    • #22348
      Walt Gifford
      Participant

      After installation and the cases cool, can you feel some play on the inner race? Are you using C4 fit? When you put the bearing in do you weight it down with a big aluminum block to keep the bearing cool and seated? The hot case can push the bearing up. There is supposed to be a hole that connects the transfer passage with the space between the bearing and the crank seal, is it open? This draws lube through the bearing from differential of pressures. After you run it on track does it still have end play in the crank? The bearings could be drifting out of the pockets. Do you have a bent axle or sprocket that could be jerking the engine shaft, does your chain pulsate are your tires balanced, frame cracked? Pull the spark plug and crank the motor over fast and listen for any metallic clank, piston hitting something. Does the piston twist going up and down? Sorry for the unicorns I ran out of zebras.

      Gif

      FAA certified jet engine and aircraft technician,
      Nicholson Speedway class champion 2001,
      Yamaha KT100 Service Center,
      41 years karting experience

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