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VTR250 Power Surge / Bog

Discussion in 'Technical and Troubleshooting Torque' started by brainfried, Feb 17, 2015.

  1. #1 brainfried, Feb 17, 2015
    Last edited: Feb 17, 2015
    Hi guys,

    I looked through some of the older threads and they didn't exactly cover my problem, so I thought I'd post a new thread and see what people's opinions are.

    I have a 2003 VTR250 with 52000Kms on it. It is due for a service now. My bike had been totally fine on Friday, when I last rode it, and I filled it up at a new petrol station with 95 about 15 minutes from home then rode home. Today, when I went to leave, I got about 250m away from my place when my bike started 'bogging'. Basically, it struggles to get past 4,000RPM-ish (unless I really push it) and it has that deep rumble sound of something being flooded or power not getting pushed through. That was as of the test ride 5 minutes ago. If I stay on the throttle, it seems to 'surge' as the power kicks in sometimes. There seems to be no problem with changing gears (smooth, easy neutral) and my clutch cable has about 10mm of free play. My question is this, is it likely that this is a fuel issue or something worse? Could my clutch be inadvertently slipped on and caused this? Or is it more likely to be fuel etc before I jump to having to get a new clutch.

    It's weird because when stopped at neutral, it revs fine as far as I can - no obvious sputtering . It is only once I have started moving, usually the top of first (and at the same rev range on subsequent gears) that it seems to happen.

    Something I have noticed - the fuel cap on my tank seems to not create a full seal (bit of movement). My bike is outside while I am at work and it has rained a bit, could rust or something similar be a factor?

    People have also said a stuck float needle, would that make sense in my circumstance?

    I am going to check the spark plugs, air filter, oil filter and oil on the weekend. Is there anything else I should check? Should I dump the fuel and get a fresh batch to test with? Is running a carby cleaner as a fuel additive to the new batch good enough in terms of cleaning the jets?

    Thanks in advance.

    EDIT: Forgot to add, that the idle speed seems fine, and the choke seems to be working as intended (as far as I am aware). DOUBLE EDIT: I had been running my bike on reserve, is there a chance I've gummed it up with sediment from the bottom of the carby? Moisture / grime?
  2. That surging and sputtering in my experience comes with either - forgetting to switch the fuel tap on, running out of fuel or little bits of crud (rust?) probably clogging up somewhere.
    I've got an inline filter, but sometimes it happens.

    For you, I'd be checking the carb if you feel competent to do so.
    You may have some junk in the float bowls etc.
  3. Crap fuel? If you think you've picked up some which might have a bit of water in it, or filth, you can easily test this by getting a syringe and a hose and pull a sample from the bottom of your tank. Supercheap auto sells nice syringes of about 150 ml. They come in handy for all sorts of things - remedying oil overfills, bleeding brakes. It's good to test the easy things first.
    • Agree Agree x 1
  4. I'd be thinking you've got some water in the fuel.
    Set the fuel tap to it's normal position and then drain the carbs.
    If it is water it should settle to the bottom of the tank. If there is water in the tank putting the bike on reserve will allow the water to be pulled to the carbs.

    google VTR250 carby drain if you need a picture of what to look for.