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how long do spark plugs last

Discussion in 'Technical and Troubleshooting Torque' started by traveller, Oct 19, 2009.

  1. Hi everyone

    Had the bike cbr rr250 serviced about 4 months ago and it has been starting fine untill 2 weeks ago now it wont start. the baike has only been riden 5 - 6 times since serviced but started at semi regular intervals. Today i took the plugs out and gave them a wipe and clean they were black at the ends and pop them back in still no go!!!! The battery also got changed. It trys but nothing. Should i just by new plugs and it should start??? Why dont spark plugs last very long??
    Anyone have any ideas??? please!!!!!

  2. Spark plugs should last a long time (years). Sometimes replacing them seems to solve a problem, but you may just be solving a symptom. Things such as running too rich or having a dirty engine can cause spark plugs to clog up. Incorrect gaps can cause rough running which in turn can cause spark plugs to become dirty.

    Often you can clean spark plugs and they will be as good as new (this involves removing all carbon deposits and crud that has accumulated in the areas around the business end of the plug). If you have other engine problems though, this is only a temporary solution.

  3. Spark plugs shouldn't be running black. Sounds like the mix is rich. If it gets bad enough it will make it difficult to start. Also it can clog plugs till they won't fire.

    If the plugs are black they possibly need more than a wipe. Did you check they actually sparked? Cleaning plugs may get you started but as stated above this may only be a temporary solution.
  4. In a correctly tuned, running engine, spark plugs can last tens of thousands of klms.
    Spark plug failure is mostly the result of other problems. Replacing your plugs are only a short term solution. Sounds to me, you have a fuel mixture problem or you have fuel leaking into the cylinder whilst the bike is not been ridden. ( You plugs will be WET ).
  5. thanks for the replies. When taken out the plugs were dry and the black just wiped off. Maybe its been so long since it has been regulary ridden there a build up somewhere. It been garaged the last 2 years and only started or riden on really short rides due to having to carry equipment for work. Im not very mechanic monded and my knowledge stops at getting spark plugs out or changing a clutch cable. So what should my next step be??
  6. Ignore this if the CBR is Fuel injected.

    My mate just had a problem with his near new Ninja 250 only running on 1 cylinder. What happened is ants were attracted to his carby's overflow pipe so they crawled up there and died. It turns out the head of an ant is enough to clog the jets. Could be that?
  7. Do not leave the choke on full when starting CBR250's. They are very prone to fouling spark plugs. Start the bike with choke &back it off as far as you can without it stopping. Most people pull the choke on full, start the bike then put on the riding gear. Better to gear up first & warm the bike with as little choke as possible.
  8. I realy can't say how long spark plugs last on a bike as I've not replaced a set on any of the modern bikes I've had. My red VFR had an additional 85000kms on it over the mileage when I bought it and I never looked at the plugs.

    I will say this, though. I know that the Mitsubishi Magna used to have a sticker under the bonnet that said that spark plugs should be "checked" after 100000kms!!

    So, I'm guessing that modern spark plugs in modern engines are going to last a long, long time.
  9. This is true for the rear bank plugs in v6 Magna but only because they are fitted with platinum tipped spark plugs, I doubt the cbr would be

    A good(conventional) spark plug will have an electrode with nice square edges, I would chaeck for that and correct gapping.

    Have you tried cranking the bike with full open throttle, no choke incase it is flooding?