Stuck gear

Discussion in 'Mounting Techniques for Bicycle Motors' started by Kaye, Sep 27, 2019.

  1. Kaye

    Kaye New Member

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    Ok so I'm very new to motorized bike ownership. I recently purchased a nel luso beach cruiser used from fb marketplace (paid 150$, then purchased a used motorized american blades mountain bike for 135$). The bike first shredded the back tire while my hubby was riding it to work, so I quickly learned how to change that out and adjust it to not scrub the frame or the chain (which is what shredded it to begin with), hubby was riding the bike 23 miles a day back an forth to work, after a few weeks or so the back tire seized up while he was riding it. So he pedaled the rest of the way to work. After getting it back home, he now rides the mountain bike. After reading many forum posts and looking at many youtube how to vids, AND today FINALLY being able to compare the two bikes with the clutch gears cover plate off, finally figured out why tje back tire seized up, ABSOLUTELY NO GREASE whatsoever on the gears inside, which I'm pretty sure seized up the smaller gear which i will post a pic of, that will not turn AT ALL. When the clutch is engaged the bike moves smoothly. Disengaged, no movement. The large gear moves less than a 1/8 of an inch, the small gear moves NONE. I desperately need help to get this thing unstuck. Uploaded pic of the gear I'm talking about. Not sure of the proper names of the engine parts.
     

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  2. Greg58

    Greg58 Well-Known Member

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    Welcome to the forum, first take the spark plug out and try to role the bike, the engine should turn over, if not the piston is siezed.
     
  3. Greg58

    Greg58 Well-Known Member

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    The small gear is on the end of the crankshaft, the bearing is on the crank not in the small gear.
     
  4. Kaye

    Kaye New Member

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    Already took out the spark plug. bike rolls fine. How do i get to the bearing??
     
  5. Kaye

    Kaye New Member

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    Also, ty for the welcome.
     
  6. Greg58

    Greg58 Well-Known Member

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    Is the engine turning over? You should hear the piston cycling
     
  7. Greg58

    Greg58 Well-Known Member

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    Did you take the screw out that holds the small gear on?
     
  8. Greg58

    Greg58 Well-Known Member

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  9. Kaye

    Kaye New Member

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    Yes i took put the screw out. It was VERY loose when i first took off the cover plate. Also, I'm pretty sure the piston isn't moving. It doesn't even try to start or turn over when the clutch is released. My hubby unintentionally ran it without oil mixxed in the gas. I'm thinking that may have stopped parts from being lubricated enough to continue necessary movement of certain inside parts???
     
  10. Kaye

    Kaye New Member

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    Short of taking the engine apart, is there a way to unstick the insides? Can I spray or squirt some carb cleaner or something similar into the engine via the spark plug hole or would that be insane to do and ruin the engine???
     
  11. Greg58

    Greg58 Well-Known Member

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    No, the piston and cylinder are probably destroyed.
     
  12. Greg58

    Greg58 Well-Known Member

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    You can take the head off and see how bad it is, it’s only four nuts.
     
  13. Greg58

    Greg58 Well-Known Member

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    At this point you can’t hurt it, take it apart and see how bad it is. Depending on how much clearance you have sometimes you don’t have to take the engine off the bike.
     
  14. Kaye

    Kaye New Member

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    Ok tyvm. I'll get started on that asap.
     
  15. MEASURE TWICE

    MEASURE TWICE Well-Known Member

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    Since advise has been given about just removing the cylinder head, on the 2 stroke engine in question, I felt maybe this be mentioned. Not sure how 4 stroke Briggs compares, but I believe an engine I think had an oil scraper ring get stuck, I freed up by taking the head off and putting like 1/4 cup oil in with the piston down a bit and forced the ring/piston/crank to get dislodged and spin smooth. I will one day take off the crankcase cover and remove the piston to see what happened, but I had another engine I used so no sweat. I thought oil scraper ring as at one time a lot of smoke out the muffler and oil got used up quick in the 4 strokes crankcase. I saved a set of used rings when I replaced them many years back. Trying to get parts is not so easy for the 80's era Briggs's. Maybe a real quick hone and swap back the rings for some extra backup engine again.
     
  16. curtisfox

    curtisfox Well-Known Member

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    MT 4 strokes are different, think 2 strokes have pins to keep rings form turning, and mainly for compression only as oil is in the gas.
    Go to a John deer dealer with your model # and see if you can get rings, Most might be still available.
    Next time you have stuck motor use Acetone 50/50 with atomic trans fluid, let it set with plug in because Acetone evaporates fast...........Curt
     

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