Question about 2002 Hyosung RX 125

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Hyosung RX125 I have had an oil leak ever since I dismantled the engine last month. There was a slight knocking, however I went out on it last weekend regardless. The bike started to lose power after 2 hours. I checked the oil level, which was pretty low. The bike now only has approx 40% power now. Does anyone know what the problem could be? I am suspecting either the piston rings or timing, however would be grateful of some advice before stripping the enging.

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  • John Jun 17, 2009

    There is no smoke from the exhaust, it's clear as normal. You say the valves may be out of adjustment; does this mean the timing is out?

  • John Jun 21, 2009

    I've checked the timing and it does seem out but only very slightly. I've also raised the head to gain access to the piston. The rings are in place but seem loose. Is this normal? How can you tell if the rings are damaged? There are traces of metal filings on the piston head, but only vey few.



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Is your bike making blue/blueish smoke while running? From the stuff you told us, it is either worn piston rings or worn valve seats, but i would personaly bet it's the valves, because the knocking sounds would be the valves being severely out of adjustment, leading to a huge loss of power and many noises. Hope i helped you :)

Posted on Jun 16, 2009

  • feralcrew Jun 20, 2009

    If there's no irregular smoke, it makes considerably less power, burns oil - I'd bet my money that the timing is severely off - it means that the valves open and close not at the perfect time that they should - too soon or too late. This hinders power, decreases fuel economy and makes unusual noises in the engine. However, it could be that the timing is right, but the valves need to be adjusted individually, using special spacers(sorry if i used the wrong word, english is't my first langage).



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