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Flames from exhaust

Discussion in 'Bling and Appearance' started by max pwr, Apr 3, 2009.

  1. I lent my bike to a mate for the last few days and he let the tank run dry. When he filled it up with premium and tried to start it it ran really rough and shot flames from the exhaust. I haven't seen it myself cos he delivered my bike back to me on the back of a ute. Bike is a 95 cbr900rr. Never had any issue before at all. We are thinking it may have water in the fuel although looking in the tank it looks fine. Plan is tonite to drain the fuel, replace with fresh stuff and try to restart. Wondering on anyone's ideas or suggestions?

  2. is the flame a bad thing?
    my mate's ninja 636 does it like all the time
    i reckon it looks sweet
  3. So it is backfiring? Incomplete combustion?
  4. you may have fouled the plugs. change the plugs as well
  5. hmmm.. unburnt fuel, not running on all cylinders.... ?

    I'd start by pulling out the spark plugs and cleaning/gapping them.
  6. Milz?

    +1 :grin:
  7. might have sucked crap into the carbies?
  8. I found your problem:

  9. bingo :)
  10. From Most of the chatter here as well as personal experience I was undr the understanding that 91 & 95 RON Was O.K. For Carbied Bikes, But 98 usually made them run like crap. So if by premium you mean 98… then that could explain the behaviour of the bike.
  11. oh? I've been running my 250R (parallel twin with carbs) on 98 RON since day one.
    should i switch to 91 or 95?
  12. Whatever it states in the owners handbook or on a tank sticker, as that will be what it has been factory tuned for. Anything else will result in performance that is 'different' - may be better, but chances are it may not be.

    If you plan on running a dedicated fuel other than the standard recommedation (ie 91 or 95 RON), I'd rejet the bike and possibly dynotune it. This way you'll get the best performance from your bike, and know that you are getting the best out of the fuel you put in.

    Cheers - boingk
  13. I ran my April on BP Ultimate without any problems... maybe that was a bad idea?

    as an aside... looks like I'm lining up one to buy this week! w00t
  14. My previous bike, curvy sv650, was shooting 30cm blue flames (as well as back firing)....turned out that a vacume had fallen off of one of the carbies and it must have been dumping too much fuel into the combustion chamber. Looked bloody awesome at night time and it stopped cagers tailgating me. :twisted:
  15. Hey Simon, at my motorbike maintenance night, they said that premium (98) is crap for bike engines because it ruins your plugs. A guy had a GSXR750 in there getting serviced, new plugs and a retune because the premium had fouled the plugs. And Premium goes 'bad' a lot quicker than regular unleaded (i.e use by date is less than a month) so if you get a dodgy batch, it will stuff the performance of the bike.

    I used to this running 98 was the way to go, but since I've switched to 91 the bike has been running much better.
  16. cheers drew, i'll give it a crack and see how it goes :)
  17. yep, don't know any bike that need to be run on 98 its just over fueling if you do. 95 is perfect.
  18. I've also been using premium-will simply switching back to regular unleaded be ok, or have i done permanent damage?
  19. flames good. :grin: :grin: :grin:
    I love swapping bikes with my mates cause when i'm following at night i can see my sv spitting blue flames when you downchange. :cool: :cool:
  20. Brings back fond memories of the 2007 Icicle Ride, chasing a few other 250s (all of us with straight-through glasspack exhausts) across the moonlit plains at 4-5am on a cloudless night, with every gearchange accompanied by a brief blue flicker from the exhausts. :)