900 mile teardown report...

Discussion in 'Motorized Bicycle General Discussion' started by jburr36, Oct 14, 2008.

  1. jburr36

    jburr36 Member

    Joined:
    Jul 17, 2008
    Messages:
    284
    Likes Received:
    0
    Ok. Summer's over and I want to be ready for next year. I hate surprises so I had an itch to see what kind of wear 900 miles did to these cheap engines to get a heads up on any problems that may arise. So I took my 80cc apart and stripped the paint and degreased all the parts. I repainted the parts that needed painted and closely inspected the critical parts.

    Here's what I found.

    * The cylinder has slight vertical scratches but it didn't affect performance.
    * Lots of carbon build up. Removed carbon and all seems ok there.
    * Bearings on clutch shaft had translucent grease...like vaseline or something. Also one had some metal flakes inside the bearing that gave it a gritty feel. I sprayed some WD-40 to clean it out and repacked both bearings. Seems okay now.
    * The clutch plate and friction wheel has ball bearings that had no oil or grease. There are 3 holes that access the ball bearings in the back of the clutch plate. I shot some grease in there being careful not to put too much. The clutch pads won't work well with grease on them.
    * at close inspection of the bottom of the cylinder I noticed a peice that look liked it was cracked however it is a casting problem (see pic). It hasn't been an issue so far so I'm not going to worry about it.
    * Cylinder head has some real cashing issues. It looks like some severe cracking but it is bad cashing. No cracks, just looks ugly (see Pic).
    * Piston looks absolutely fantastic for 900 miles after I cleaned the carbon off.
    * Needle bearings look great and so do the main crankshaft bearings.
    * Replacing all the screws and washers with stainless steel due to the climate here.
    * Yes, That's why I painted my magneto green and the magneto rotor vivid purple.

    Now it's time to reassemble the motor. I'm thinking of electroplating a new motor I might get instead of painting it.

    Time to get to work.

    P.S. That starter motor will work nicely once I maching the parts to make it fit. Will take some time for that though.
     

    Attached Files:

  2. jburr36

    jburr36 Member

    Joined:
    Jul 17, 2008
    Messages:
    284
    Likes Received:
    0
    More Pics...

    P.S.S. Your eyes aren't deceiving you, that is 3 intake manifolds there. Boy Go Fast auctioned off a lot of 3 for $12.00 or so.
     

    Attached Files:

    #2 jburr36, Oct 14, 2008
    Last edited: Oct 14, 2008
  3. old motorbike

    old motorbike New Member

    Joined:
    Sep 21, 2008
    Messages:
    352
    Likes Received:
    0
    Nice job and great pictures. It looks as though the Chinese are getting their casting a bit better than it was.
    I wonder what can be done with porting for a little more power?
     
  4. Cr9ck

    Cr9ck New Member

    Joined:
    Sep 7, 2008
    Messages:
    57
    Likes Received:
    0
    nice man let us know how it goes. Im really interested about your freewheel and electric / pull start.
     
  5. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

    Joined:
    Jan 8, 2008
    Messages:
    11,529
    Likes Received:
    3
    Nice report...keep us updated.
     
  6. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

    Joined:
    Jan 8, 2008
    Messages:
    11,529
    Likes Received:
    3
  7. jburr36

    jburr36 Member

    Joined:
    Jul 17, 2008
    Messages:
    284
    Likes Received:
    0
    I'm contemplating on a new head because it does look like [email protected] but when I turn it over it looks beautiful.
     
  8. Goat Herder

    Goat Herder Gutter Rider

    Joined:
    Apr 28, 2008
    Messages:
    6,251
    Likes Received:
    3
    Acumma Mentadata [ from the cartoon] don't worry be happy its all good!By the way Bobby Mechfarren The song Don't Worry Be Happy he commited suiside, I still dig it your good man ride on me boy(^)its gonna be ok
     
  9. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

    Joined:
    Jan 8, 2008
    Messages:
    11,529
    Likes Received:
    3

    In this case, that's all that matters.
     
  10. Dan

    Dan Staff
    Staff Member

    Joined:
    May 25, 2008
    Messages:
    12,641
    Likes Received:
    62
    Don't think my last chinagurl looked that good when it was new. Nice job!

    Oh man, ya scared me! I had to research Bobby Mechfarren thing. (great song!) Turned out to be a rumor, Thankfully. snopes.com: Bobby McFerrin Suicide Rumor

    Sorry. I ramble off topic again
     
  11. amealnet

    amealnet New Member

    Joined:
    Sep 19, 2008
    Messages:
    21
    Likes Received:
    0
    do you think a gas/oil mixture adjustment would improve engine wear? or maybe a sparkplug change would help?
     
  12. jburr36

    jburr36 Member

    Joined:
    Jul 17, 2008
    Messages:
    284
    Likes Received:
    0
    Depends on what you are adjusting it from or to and what type of plug you choose. I usually follow the oil manufacturer's instructions for the oil and I go for the forum member's recommendations for the plug. Their experience with the correct plug temperature is based on trial and error.

    I was quite surprised to see how well my engine was lubricated when I tore it apart.
     

Share This Page