Eagle sports 125

Last post 04-28-2014 11:58 PM by pyrah. 3 replies.
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  • 04-28-2014 06:58 PM

    Eagle sports 125

    This may help some guys!

    A month ago a young mum asked me to check out why her Eagle Sport  125cc Scooter would not start.

    12,700 km on clock . 2007 model.

    (I only muck about with cars normally.)

    Checking.-Nothing at all.

    Someone had fitted a kill switch between battery negative and frame.

    Then it cranked over Ok.

     No spark - side stand has a limit switch, put on full stand- a weak spark then appeared.

    Still no ignition.

    Carby intake filter removed, carby throat blanked with a sheet of rubber for a few revs. Plenty of fuel observed  from metering needle on main jet. Throttle wound full open and piston on main jet held open with a screwdriver. Fired up OK. Ran very well.

    Quite surprised me how much power it had.

    Stopped and started a few times normally.

    Next day when cold- no ignition.

    Ripped the carby apart.

    It’s an SU type operated by a diaphragm

    Has 3 jets .Main, idle and choke. Puzzled out how it worked and pondered over an electric choke. Is it a solenoid control ? No it’s a heater!!!

    Everything was blown through  and proved clear. All gaskets renewed, all flexible hoses renewed( as they were dribbling petrol)

    Everything appeared to be hunki-dori with the carb. Still no ignition.

    What about the weak spark?   Ignition coil primary winding resistance 0.2 ohm. Lowest I’ve ever come  across. CDI unit was fed from 12v and discharged abt 30v open circuit.

    Checked spark timing with timing light. Seemed a bit close to TDC but no adjustment available on pickup coil. It’s resistance was OK.

    Pulled the carby apart again and plugged the float chamber vent hole above the electric choke jet with a steel ball and supa glue to get a bit more liquid through.

    Bought an Iridium plug for $18. Nice blue spark.

    Guess what- no ignition!!

    Borrowed a compression tester from a neighbor .The car one I normally use wouldn’t fit in the confined space of the scooter.

    Bashed the guts out an old spark plug for the 10mm fit to cylinder head.

    Silver soldered some fittings to it that fitted the flexible hose on the tester.

    Cranked over. Only 80psi. That’s been the problem all the while!!

    Had not wanted to start ripping engine apart as moulded  gaskets  etc might be hard to get.

    But now I have to

    Rocker cover removed.

    Wow it’s an overhead camshaft!

    Where’s the clearance on the exhaust? Backed off the tappet until I could jiggle the rocker.

    Now compression 150psi. Great it’s not a ring or burnt valve problem.

    Bit of sealant on rocker cover.

    Removed steel ball from carby.

    Bingo - after 2 revs it fired.

    Been riding it around and I must admit it’s quite exhilarating.

    I’m thinking that the clearance had reduced on the exhaust valve as the seat in the cylinder head may have been pounded into the alloy over the years.  When hot expansion of the head had removed the clearance so it ran OK.

  • 04-28-2014 08:40 PM In reply to

    Re: Eagle sports 125

    Welcome steamseadog

    Wow well done most scooter shops wouldn't have touched a Chinese scooter with a barge pole Yes

  • 04-28-2014 09:08 PM In reply to

    Re: Eagle sports 125

    And the prize for "Best first post on the forum" has just been decided!


    Welcome, and please stick around. I for one would enjoy hearing more stories of mechanical ingenuity.

    4 years and 20,000 K's later, I'm still scootering, and you guys are stuck with me!
  • 04-28-2014 11:58 PM In reply to

    Re: Eagle sports 125


    And the prize for "Best first post on the forum" has just been decided!


    Welcome, and please stick around. I for one would enjoy hearing more stories of mechanical ingenuity.


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