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mucho backfire while in gear downhill

Discussion in 'Bling and Appearance' started by DUK35, Aug 28, 2007.

  1. went on the usual Eastside weekly coffee meet last night and we went down the hill at coogee going towards maroubra. while I was going down hill I left the bike in 3rd gear and took my hands of the bars to stretch a little while the bike rolls down the hill smoothly. However - I kept hearing the pipes backfiring rapidly - not quite a *BANG BANG* backfire but a *I sound like a drag car gearing down* backfire.

    plop ploploplop ploplop ploplop - yeah you get the idea.

    it happened a few times but last night it was louder than usual.... or maybe cos I was riding with my visor up so I could hear everything.

    mind you - my baffles are completely out and the back plate went with it so my pipes are pretty much hollow at the tip.

    it this the sound of the bike asking you to re-jet it? or is it time to change my oil? or prolly both? or is it telling me that it's about to fall apart? :p
  2. try winding the idle mixture screws out a bit.
  3. And the problem is ?
    Every bike I've ever owned that I have debaffled or put a 4 into one exhaust on, has always backfired down hill in gear.
    The natural venturi effect of engine braking drags excess fuel into the cylinders and not all this gets burnt until it hits the 'hot' spots in the exhaust.

    If you don't like it don't ever by a big twin cyl bike. :p
  4. Yeah, it's just a lean mixture caused by idle over run at high rpms. It's a lovely sound, get to enjoy it!
    Lean is fine in this instance, as there is no load.

    Regards, Andrew.
  5. Duk35 mate! why are you complaining about that glorious sound?
  6. well I do like the sound! just paranoid if it may brake my engine - I find it hard enough already keeping up with you hoons! lol

    I guess it sounds good then - nothing to worry about :p
  7. Engine braking is one of my favourite features on my debaffled VTR. Specifically the burble sound with occasional backfire thrown in :)

    Just dont do it when the cops are around.
  8. Of course it fraps and bangs on the overrun. It's a vee for goodness sake.

    They all do it unless you retain all the stuff that the factory spent billions of yen developing to stop it. As soon as you change anything like the pipes or air filter, it come straight back.

    It's particularly nice following a minimally baffled vee down a long hill at night when you can watch the little blue flames from the pipes.