neos 70cc

Discussion in 'Scooter Tuning' started by metalizzer, Oct 5, 2021.

  1. metalizzer

    metalizzer New Member

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    13
    Hi all
    my scooter starts fine runs great . but after a few minutes it looses power. did it with original 50cc and does with the naraku 70cc kit. I thought it could be a burned head gasket but the head was clean no leaks. I`m using the original carb with an 85 main jet. Already bought a chinese dellorto 21 and a conical filter to install also gonna put an aerox exaust.
     
  2. The Messenger

    The Messenger Active Member

    Messages:
    163
    it sounds like you maybe running too rich,

    you can get away with running rich on a cold engine, but once the engine heats up it wont run great.. if at all.

    take the spark plug out and see what colour it is, if its very dark or black thats your problem.
     
  3. metalizzer

    metalizzer New Member

    Messages:
    13
    yes it seems so. i opened 3 small holes on the original air box and gave 1 more turn out on the air screw. she´s not perfect but much better. I just recieved the 21 chinese dellorto today and thinking of changing the exaust for an aerox one... what do you think?
    thanx for your reply and help.
     
  4. The Messenger

    The Messenger Active Member

    Messages:
    163
    The chinese carbs can be a bit hit or miss for quality, your much better off with a genuine Dellorto carb.
    but as you have already bought it I guess its worth a try.

    The Naraku 70cc is quite a low revving cylinder kit with a modest improvement over the stock cylinder, and will work perfectly fine with a std carb and exhaust. You can of course fit a sports pipe to get a little more power but dont go mad, a really revvy pipe will push the revs past the point the kit makes power. A leo Vince TT or similar is all you need really...
     
  5. metalizzer

    metalizzer New Member

    Messages:
    13
    i can get an original Yamaha aerox exhaust very cheap. is nt it better then Original Neos one?... a leo vince is always expensive here. around 150€ an aerox used one i can get around 30€. thnx
    https://www.olx.pt/d/anuncio/peas-yamaha-aerox-IDGnyR8.html?reason=observed_ad
    https://www.olx.pt/d/anuncio/escape-de-scooter-aerox-IDGGP3I.html?reason=observed_ad
     
  6. The Messenger

    The Messenger Active Member

    Messages:
    163
    About 15 years ago, I had a speedfight 50 LC as a get to work bike.

    I fitted a 70cc sport cylinder, and ran it with the nice quiet stock exhaust, and the std 12mm Gurtner carb and stock air box.

    It was abit quicker than 50cc scooters with a noisy sport pipe, a few who tried got left behind scratching their heads trying to figure out why :D
     
  7. metalizzer

    metalizzer New Member

    Messages:
    13
    o think this scooter has a problem that i did´nt figure out yet... she still looses power after hot and today she did the same that it did the other day before you told me it could be to rich. i´m going on full throtle and she turns off... then it starts again!
     
  8. The Messenger

    The Messenger Active Member

    Messages:
    163
    it sounds like you have the wrong main jet in still.

    what is the stock main jet size for your carb, and what size are you running now?
     
  9. metalizzer

    metalizzer New Member

    Messages:
    13
    had a 72 and now 85
     
  10. The Messenger

    The Messenger Active Member

    Messages:
    163
    going from a 72 to an 85 is a massive jump up, about 19% bigger.

    I would try a smaller main jet something around the 78 region, and see if that improves the wide open throttle issue.

    a mild sport 70cc kit with a stock pipe should only really need a 5% increase in jet size.

    A sports pipe however would need about a 10% increase.
     
  11. metalizzer

    metalizzer New Member

    Messages:
    13

    it was the one i asked for but they only had 75 and 85. i bought both... should i try the 75 or do it when i find the 78?
    thnx
     
  12. The Messenger

    The Messenger Active Member

    Messages:
    163
    put the 75 in and report back
     
  13. pembo_99

    pembo_99 Member

    Messages:
    164
    Find a jet kit. Polini do a set of dellorto jets, usually about 8 -10 in a pack going up in small increments. These kits are worth the weight in gold. Start quite rich and ride it. Change to a leaner jet next then ride again. Keep changing them step by step, until it has most power and overrev. When you get to a point that the next jet down hasn't improved power, and sounds possibly too clean, consider one jet richer to be on the safe side. Long winded but quite simple and a good learning kinda job.
     

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