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Bad fuel - Bike now starving?

Discussion in 'Technical and Troubleshooting Torque' started by Toefa, Oct 20, 2007.

  1. Hi Guys, hoping someone may have a quick fix for this problem....

    I was in desperate need for fuel a few weeks ago and had to pull up at a small no name servo, where i filled up with straight unleaded. It was crap fuel and caused what felt like a loss in sharpness to throttle response and a overall dullness... I ran the shit through as quickly as possible and chucked in some 98RON at my next fill up. I noticed a difference almost straight away. BUT..... Even after a couple of fresh tanks later, the bike is still not 100%. In certain points of the rev range it sounds as if the bike is starving for fuel. Almost like the sound the bike makes just before i need to switch to reserve? I am assuming the crap fuel has somehow 'dirtied' my carbs but cant be sure... Is there anyway to clean her back out? I really dont wanna have to rip the carbs off and have them cleaned at this stage, cause the bank balance doesnt allow for it. Anything you guys could suggest? Am i even looking for problem in the right place?

  2. If you're sure you have a problem get down to an auto parts shop and get a bottle of fuel system cleaner. Good servo's sell it to. It's sold under many brand names.

    As for your issue it could be many things.
  3. It's really not recommended you run premium unleaded in cbr250rr's, the detergent & all that other crap they trow into the petrol doesn't help your engine & carbs. Find a good shell & fill up with basic unleaded. I also hear bp ultimate is a good unleaded for the bike, but i find the cbr250 pull a shit load better with shell unleaded(try 2 tanks & get back to us with wat you think)
  4. My FZR250R runs like crap with PULP in it. Always stalls and bogs down. My FZR was just not jetted to run on PULP
  5. Thanks guys, the thing is... my normal routine was run two tanks of normal unleaded, then one of PULP and it has never missed a beat.

    I thought that a fuel system cleaner may hurt the bike, if thats not the case, i will definitely run some through?

    To further describe the symptoms, the exhaust note is tinnier, again like when your fuel is running out. The bike is less responsive in the low end, but when worked up to 12-13K+ RPM seems to come back to normal.
  6. everyone has their own preference for fuel - just make sure it's a reputable brand and fresh.

    I use ultimate and don't have an ounce of issue with it. used optimax once a couple of years ago and fouled the plugs. everyone has a fuel story.

    put a good inline filter in - sintered bronze ones work well.

    if you have dodgy carbs, take them off and soak them in methylbenzine for 24 hours. make sure you pump it through thoroughly before leaving them immersed. this will remove any shellac and scum deposits in the float bowls and in the passages.

    flush them with clean MB after removing from overnight bath.

    i have 28K on the clock so it might be a little different for others with high km cbr's

    beware: lots of people fk with cbr's and end up causing more problems than they started with.

    follow the KISS principle. and as soon as you can clean those carbs. a proper job will keep you rolling for a long time - unless you put another tank of sht fuel in it.