YN50 Bogging Down

Discussion in 'The Workshop' started by mrpetrepp, Apr 20, 2017.

  1. mrpetrepp

    mrpetrepp Member

    Messages:
    35
    Hi guys.

    Today I was putting new rollers (5.5g) into my Yamaha Neos (2004). All went well then I went for a quick ride around the block, I got to the bottom of my hill and paused at a junction then the bike cut out - after that, it would start, idle fine etc but it will bog down under full throttle. I have checked the airbox and when I block off the snorkel using my hand, the bike continues to run -- could this mean that there is an air leak?

    I plan on checking the color of the spark plug. Could someone tell me what the symptoms of a rich running / lean running bike is?

    My next bet is to change the main jet, I purchased an 82 and an 86 main jet because I suspected it wasn't jetting right due to bad fuel economy (30.4mpg), lag in the throttle, issues with idle and power when the bike was warm. because I was wondering what else could be causing this issue. I don't have any oil in my air filter but it was at least ride-able before I changed the rollers.

    Any help would be appreciated
    I'm selling the bike in a week or so because I'm upgrading to a Honda NS125R, so really need to get it sorted because I want to enjoy the fun and simplicity of a ped while I have it :) Gonna miss my little Neos.
     
  2. Stevep

    Stevep Well-Known Member

    Messages:
    5,895
    If blocking the snorkel changes the way the bike runs, then you've answered your own question.
    Too much air getting in.
    Could be that while you did the rollers it's managed to pick up some crap into the carb jets.
    Not a big job to strip it out and blow it through, even if it's just to rule it out the equation.

    Plug needs to be a nice dark rich ginger colour, too black it's rich, too white it's lean.
     
  3. gilburton

    gilburton Active Member

    Messages:
    558
    Did you have to move the air filter housing to get the belt cover off? If so check all hose connections.
    If all you did was replace the rollers then as said the fault must be airbox/carb related or(as said) possibly disturbing the filter has allowed dirt to get in.
     
  4. mrpetrepp

    mrpetrepp Member

    Messages:
    35
    Blocking the snorkel doesn't affect how the bike runs at all. I didn't have to move the air filter to get the belt cover off although I may have disturbed it when I was stripping the bike down. I will take the filter apart and give it a clean.

    Thanks for the suggestion.
     

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