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Thread: Poor performance

  1. #1
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    Poor performance

    Hello, I've been having some problems with my gilera dna 50cc ( same as aprillia sr engine), wondering if someone could help
    So first of all my Dna doesnt idle no matter how many turns i turn my idle screw in, and second of all my Dna has poor acceleration if I give full thottle, my bike is having huge trouble moving, after moving a little bit it will start accelerating and will run good when not stopping. Bike is pretty much stock except giannelli extra v2, 4.75g roller weights, red clutch springs, oh and also my jet is 80 everything in the engine is new, can't find the problem

  2. #2
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    Quote Originally Posted by Klaudutis View Post
    Hello, I've been having some problems with my gilera dna 50cc ( same as aprillia sr engine), wondering if someone could help
    So first of all my Dna doesnt idle no matter how many turns i turn my idle screw in, and second of all my Dna has poor acceleration if I give full thottle, my bike is having huge trouble moving, after moving a little bit it will start accelerating and will run good when not stopping. Bike is pretty much stock except giannelli extra v2, 4.75g roller weights, red clutch springs, oh and also my jet is 80 everything in the engine is new, can't find the problem
    Oh and also whenever my bike goes into power band it's all good.

  3. #3
    apriliaforum expert
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    better check the reed valve/the idle jet and the sparkplug. the main jet is too big i think. have you messed with the airbox?

    then put the stock roller weights back maybe. you need a rpm gauge to find 8000-8500rpm with the rollers anyway.
    --- diploma for engine repair in 2012 ---

    derbi bullet 2006 - piaggio AC - malossi T.C. half - custom GPS dash - TPR 70CC - topperf crank - vl13 reed and spacer- yamaha rt180 kickstand - giannelli shotV4 - phbg 21mm - doppler mesh top venturi filter

    complete wtp volta bmx 2012 - sanko seamless japanese cromoly heat treated and blue printed frame - 21lbs

    1992 lt250r suzuki quadracer - maier plastics -chromed shearer pipe - chromed works suspension - ++++++++ - 220lbs

    previous vehicles - subaru legacy turbo 1991 - mazda mx6 turbo 1990.

  4. #4
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    Quote Originally Posted by sublunacy View Post
    better check the reed valve/the idle jet and the sparkplug. the main jet is too big i think. have you messed with the airbox?

    then put the stock roller weights back maybe. you need a rpm gauge to find 8000-8500rpm with the rollers anyway.
    Reeds are brand new, the airbox has been messed with around when i bought the bike, there is two small holes in the airbox.
    Well my friend has exact same setup and everything is ok for him, his jet is 80 also.

  5. #5
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    well it must run very good if you dont want to do a 2 stroke tune up. maybe your right. it could be be black magic or perhaps the russians did it.

    Quote Originally Posted by sublunacy View Post
    better check the reed valve/the idle jet and the sparkplug. the main jet is too big i think. have you messed with the airbox?

    then put the stock roller weights back maybe. you need a rpm gauge to find 8000-8500rpm with the rollers anyway.
    --- diploma for engine repair in 2012 ---

    derbi bullet 2006 - piaggio AC - malossi T.C. half - custom GPS dash - TPR 70CC - topperf crank - vl13 reed and spacer- yamaha rt180 kickstand - giannelli shotV4 - phbg 21mm - doppler mesh top venturi filter

    complete wtp volta bmx 2012 - sanko seamless japanese cromoly heat treated and blue printed frame - 21lbs

    1992 lt250r suzuki quadracer - maier plastics -chromed shearer pipe - chromed works suspension - ++++++++ - 220lbs

    previous vehicles - subaru legacy turbo 1991 - mazda mx6 turbo 1990.

  6. #6
    apriliaforum prov-nov
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    Quote Originally Posted by sublunacy View Post
    well it must run very good if you dont want to do a 2 stroke tune up. maybe your right. it could be be black magic or perhaps the russians did it.
    Yea it's just picking up rpm's slowly, and impossible to get it to idle no matter how many turns do i turn in idling screw.

  7. #7
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    get a new sparkplug. look at spark colour is thin and blue or hot white/yellow kernel.

    remove the reed and try to suck past the valve. it should snap open evenly on both sides and pop closed perfectly tight.

    remove and clean both jets with wd40 and a toothpick and get a fuel filter.

    remove the aftermarket rollers or actually check the rpm with a gauge.

    look for fluid leaks - they are air leaks on two strokes.

    finally you can tune the needle clip height since everything has been fixed/tuned up.
    --- diploma for engine repair in 2012 ---

    derbi bullet 2006 - piaggio AC - malossi T.C. half - custom GPS dash - TPR 70CC - topperf crank - vl13 reed and spacer- yamaha rt180 kickstand - giannelli shotV4 - phbg 21mm - doppler mesh top venturi filter

    complete wtp volta bmx 2012 - sanko seamless japanese cromoly heat treated and blue printed frame - 21lbs

    1992 lt250r suzuki quadracer - maier plastics -chromed shearer pipe - chromed works suspension - ++++++++ - 220lbs

    previous vehicles - subaru legacy turbo 1991 - mazda mx6 turbo 1990.

  8. #8
    apriliaforum prov-nov
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    Quote Originally Posted by sublunacy View Post
    get a new sparkplug. look at spark colour is thin and blue or hot white/yellow kernel.

    remove the reed and try to suck past the valve. it should snap open evenly on both sides and pop closed perfectly tight.

    remove and clean both jets with wd40 and a toothpick and get a fuel filter.

    remove the aftermarket rollers or actually check the rpm with a gauge.

    look for fluid leaks - they are air leaks on two strokes.

    finally you can tune the needle clip height since everything has been fixed/tuned up.
    Well spark plug is new, the colour of it is Brownish, just like cappuchino or caramel.

  9. #9
    apriliaforum expert
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    better get a mechanic since you cant locate any problems
    --- diploma for engine repair in 2012 ---

    derbi bullet 2006 - piaggio AC - malossi T.C. half - custom GPS dash - TPR 70CC - topperf crank - vl13 reed and spacer- yamaha rt180 kickstand - giannelli shotV4 - phbg 21mm - doppler mesh top venturi filter

    complete wtp volta bmx 2012 - sanko seamless japanese cromoly heat treated and blue printed frame - 21lbs

    1992 lt250r suzuki quadracer - maier plastics -chromed shearer pipe - chromed works suspension - ++++++++ - 220lbs

    previous vehicles - subaru legacy turbo 1991 - mazda mx6 turbo 1990.

  10. #10
    apriliaforum newb
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    Don't know if you are still having problems (2 weeks later)... Assuming you are getting good compression from the new parts, if the engine won't idle and the plug is not fouled, then you almost certainly have a problem with your carb idle circuit, or possibly your float level. In the old days you could measure float levels but I don't know if that is practical on one of these carbs. If it was OK before, and it was treated gently and assembled correctly, then it is probably OK. If the floats got bent or you are unsure about their setting then you should look into it. With the idle circuit, make sure that carb cleaner will come through all of the orifices and channels that make up the idle circuit. Dried gas (from sitting many months) can clog up those passages and kill your idle. Is your idle mixture screw set right? If it was out for cleaning (which it should have been) was it put back in the right number of turns? If you don't know, start with 1,75 turns.
    Good luck.

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