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  1. #1 Need help please 
    C-Moto Noob
    Join Date
    Apr 2019
    Location
    Belgium
    Posts
    6
    Im going to cut a long story short Smile My wife bought me a semi used bike with 9000km as a gift. It was dropped off at my home by seller qnd his wife. Just for the record; my wife knows nothing about bikes. She really just wanted to surprise me. Problem is bike has some issues and I would like to hear and get some info and advice before doing anything to it.

    Its a KSR Grs 125cc 2017 QJ157FMI-2B.

    From what Ive read this is a chineese copy of the Suzuki GS125 engine

    These are the problems:

    1st gear+2nd gear bike pulls and rides ok. ( at least i think it feels ok for a 125cc )
    3rd gear gets to about 61/67 km/h but it takes long to reach that speed depending on head wind. Road is a flat. I would think that this is very little.
    4th gear top speed +- 71/76 km/h. Really feels like its lacking power and struggles to keep that speed.
    5th gear : forget about it. Speed drops down queit a bit:

    This is the speedometer reading of speed in km/h

    From what I have read , bike should do around 95 km/h. I know its a small bike, im a heavy bloke (103kg pure beer belly::: i mean pure muscle) Smile , but surely it should reach 90 km/h no problem. I have read some ppl get 100/110 km/h out of this bike.

    I can change gears no problem, but I have also noticed that cluch feels like its worn. If you are riding and pull clutch in and drop it quickly, you should feel that jerk of engagment, but it almost feels like a slip disk clutch (hope im making sense ). It takes long for clutch to engage again and its on the end of the lever;

    Could that be the problem of lack of speed and power?

    I checked the air filter today. Its a new one.
    I checked spark plug and compared to chart and its burning ok. Looks new. It is correct spark plug according to manual.
    I checked the chain tention and i tightened it to spec as it was very loose.
    Engine turns and sounds healthy. If I open choke with motor warm, it cuts out engine, which is normal.

    Saturday im going to open up to have a look at clutch for signs of wear and tear.

    Hope Ive been able to explain well enough. Any questions feel free to ask.

    *** UPDATE ***

    26/04/2019 : 11h26
    Just a small update. Ive taken apart the bike to reach the carb to clean it. There is a small black box that goes to engine and main air filter intake pipe. I noticed it had water in it. It has a little tap connected to it. I opened it up and drained water. Guess it is not supposed to be with water. After lunch I will be cleaning carb.

    26/04/2019 : 13h50
    Cleaned carburator out. Did have some brownish like dirt water markings in float cup. Assembled it back together and took it for a spin. Little better but still 4th in the 76/78 km/h range.

    26/04/2019 : 14h55
    Took out filter from inside filter box. Took it for a spin and it did have peak moments of 85 km/h. So more air intake = little more speed/power
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  2. #2 Re: Need help please 
    Senior C-Moto Guru humanbeing's Avatar
    Join Date
    Dec 2008
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    1,493
    QJ = https://en.wikipedia.org/wiki/Qianjiang_Motorcycle often branded as Keeway in int'l market QJ157FMI-2B shop manual https://shop1897.hstatic.dk/upload_d...vicemanual.pdf
    If it's a CV carb. The diaphragm may torn a pinhole somewhere
    Anyway the bike had such mileage. At least check the valve clearance & electric system (GS125 need reliable DC supply) 1st
    Don't 100% trust that owner's manual. Just replace it w/ a new Japanese brand (NGK/ Denso) equivalent. Suzi said replaces it every 8000 km. QJ said relaces it every 6000 km.


    Heat rating: Similar to NGK
    R Resistor type NGK= R
    T Projected (凸 Tū) center electrode insulator NGK= P
    C Copper core center electrode NGK= S
    Chinese "B" (10mm) = NGK "C" | Chinese "D" (12mm) = NGK "D"
    Last edited by humanbeing; 04-27-2019 at 09:52 AM.
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  3. #3 Re: Need help please 
    C-Moto Noob
    Join Date
    Apr 2019
    Location
    Belgium
    Posts
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    Quote Originally Posted by humanbeing View Post
    QJ = https://en.wikipedia.org/wiki/Qianjiang_Motorcycle often branded as Keeway in int'l market QJ157FMI-2B shop manual https://shop1897.hstatic.dk/upload_d...vicemanual.pdf
    If it's a CV carb. The diaphragm may torn a pinhole somewhere
    Anyway the bike had such mileage. At least check the valve clearance & electric system (GS125 need reliable DC supply) 1st
    Don't 100% trust that owner's manual. Just replace it w/ a new Japanese brand (NGK/ Denso) equivalent. Suzi said replaces it every 8000 km. QJ said relaces it every 6000 km.


    Heat rating: Similar to NGK
    R Resistor type NGK= R
    T Projected (凸 Tū) center electrode insulator NGK= P
    C Copper core center electrode NGK= S
    Chinese "B" (10mm) = NGK "C" | Chinese "D" (12mm) = NGK "D"
    Hello Humanbeing

    Thanks for info. Was helpfull

    I reset valves and now its responding and driving much better :-)

    Thanks
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