"Happy Time" wristpin bushings

Discussion in 'General Questions' started by srdavo, Jun 24, 2007.

  1. srdavo

    srdavo Active Member

    But I'm not laughing.....1st, let me say this 48cc has been run (hard) since 2005. It still runs strong.
    the funny sound....almost sounds normal for a 2 stroke. you know....the popping, ring-ring-ring ya get when you let off the gas. really loud. At 1st I thought it was an exhaust leak, so I put a new gasket on....no change.
    ok...there is no unusual sounds while accellerating. Runs really well. but anytime I back off the throttle I get this loud metalic popping. It seems fine when the engine is under a load.

    any ideas?

  2. thatsdax

    thatsdax Guest

    It may be.....

    It could be your wrist pin bushing has some play in it . Check and see.
  3. srdavo

    srdavo Active Member

    yes, it was the wrist pin bushing!! Play wasn't the word for it. Slop?
  4. srdavo

    srdavo Active Member

    this wrist pin thing is contagious. This 55cc bike has started making the same sounds as the 48 I just almost fixed. will be 2 years old in August. maybe 2000 miles.


  5. gone_fishin

    gone_fishin Guest

    i'll just mention that in my case, see above, there was still just a tad of brass left, so i never had pin-to-rod contact/wear/damage, i expect a smooth repair, any tips would be most welcome.

    reality check: locally we've decided we need to treat the "happy time"s more like 20mph commuters and less like 30mph circle-trackers. we tore down quay-n-cruzin's just to be sure, all is well.
  6. srdavo

    srdavo Active Member

    sounds practical....prolly safer......but not as much fun. :lol:

    no tips from me....I did it the hard way.
    I have my new bushing installed.....but in the process off punching it out of my spare connecting rod....and pressing it into place on my connecting rod, the darn thing "swelled" inward. yes the wrist pin fit fine...before I messed with it. I slowly honed the bushing to fit my wrist pin. it looks & fits good. time will tell if it holds up.

    plus, I broke a ring re-assembing it. :lol: :p Yup...the hard way!!!

    I ordered rings & bushings from Dennis Foster this morning
  7. Tips

    Hi put your wrist pin bushing in the freezer, and it will shrink a little then press it in, Mike
  8. gone_fishin

    gone_fishin Guest

    too cool, mike...pun intended! :lol:
  9. azbill

    azbill Active Member

    Re: Tips

    that is a very good tip Mike
    I am sure it will get lots of use around here
  10. thatsdax

    thatsdax Guest

    I have them

    Seems to be a weak point..With some. What was your mix ratio? Out of several thousand motors I have had around 15 or so with a premature worn bushing. When you replace the bushing, drill two more smaller oil holes off center and approximately 120 degrees apart. If you can. Keep mix around 20:1 . Thanks..Enjoy the ride.
  11. Kielohawk

    Kielohawk Guest

    Thatsdax, Do you recommend synthetic? I thought when using synthetic you did'nt have to mix so much oil into the gas? Should I switch to dino 2-cycle oil and mix at 20:1? When my bearing went out I was running 25:1 synthetic. Btw, thanks for the cylinder! It's working great. I think i am going to be ordering another bushing to have a spare around.

  12. rcjunkie

    rcjunkie Guest

    Go with roller bearing replacement and then run at 32-40:1 oil with no worries. Longer life and more friendly on environment.

    Oh, synthetic offers no protection advantage over conventional 2 stroke oils other than cleaner burn. If you want better lubrication and protection from overheating or running hot then using Klotz techniplate 2 stroke oil which contains 20% degummed castor oil is your best bet. Its flash point is 400-440 deg F and Amsoil and other syn oils flash point is 200 deg F.
  13. thatsdax

    thatsdax Guest

    Where can one get?

    RC ...Where can one get a roller bearing replacement? Lets us know..Thanks....