TW125 Uphill issue
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  1. #1
    Junior Member manxjason's Avatar
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    May 2015

    TW125 Uphill issue

    Hello chaps, hope you don't mind me including this post under the technical topic - I'm assuming the mechanics are pretty similar between the 125 and 200 models.

    I was out on my 02 TW125 last night. In a couple of areas, on the flat and in second gear, the bike felt quite gutless - it didn't want to accelerate. Later on the ride I took it up a relatively steep hill where I began losing revs. After dropping in to second, the revs continued to drop to the point where I was going very slow indeed - it felt like the bike wanted to give up. I had to pull in, and pull away again in first to get the revs back up. It was bloody windy mind, and i think it was a headwind.

    I took another hill home, this time got up to 2nd gear in high revs and managed to keep it that way to the top.

    This morning, the bike felt great. No acceleration problems - in fact it felt much better. This was all downhill and on the flat.

    I replaced the air filter. I have a replacement plug to go on it too. Oil levels seems fine, bike ticks over nicely and starts straight away every time.

    Think there could be a fuel/air mix issue with the bike or just the little engine struggling to carry my fat 16stone arse up the hill in windy conditions?


  2. #2
    Super Moderator Purple's Avatar
    Join Date
    Mar 2015
    Ynys Môn
    Sounds like a fuel /air mix issue.

    If you ride close to sea level - ignore what I’m about to say — if you ride at altitude, it might explain a bit about your predicament.

    With TW200’s, the only time they lose “significant” power on hills (assuming the bike is set up correctly), is at altitude. Even at 16 stone, into a head wind, up a hill — you should have been able to get up to 40mph on that 125.

    But on that particular night, the high winds indicate a change in barometric pressure — either high pressure or low pressure will have an effect on the air/fuel mix — and if your carb is set up “border line” for your altitude, then this may have been just enough to tip it over the edge.

    The fact that the bike was fine the next day tends to confirm this.

    Of course, if you’re nearer sea level, then I’m talking out of my arse ……..

    Sorry I can’t be of more help — but this forum is set up for TW200’s — not TW125’s. There may be similarities between the two, but anticipating your next question (what should my jet size be at xxxx Ft above sea level) — I have no idea.

    If you want some honest advice — at 16 stone in a hilly area — you might want to consider getting the 200 — then we would be able to answer in more detail ……….
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  3. #3
    Senior Member scotti158's Avatar
    Join Date
    May 2013
    Groton, NY
    Quote Originally Posted by manxjason View Post
    or just the little engine struggling to carry my fat 16stone arse up the hill in windy conditions?

    Know anyone with aTW125 you could ride to compare with? How heavy is 16 stones?
    2013 Yamaha TW200

    1996 Yamaha TW200

    1995 Kawasaki KLR650

    2002 Yamaha RoadStar 1600 with sidecar

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  5. #4
    Senior Member Fred's Avatar
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    Dec 2011
    Turtle Wrangling the Sierras
    A stone weighs 14 US pounds so 16 stone = 224 pounds.
    I first thought clogged air filter at beginning of thread until OP said filter was new. Perhaps the filter was over oiled?
    2003 TW200 "Betty Boop"
    2006 TW200 "Nibbler", a.k.a. “Mr.Gizmo"
    Hidden Content All Things Considered I’ld Rather Be Motorcycling

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