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HELP! Spark plugs

Discussion in 'Technical and Troubleshooting Torque' started by dishy, Mar 23, 2007.

  1. I tried to change my sparkplugs today. I thought this would be a relatively simple procedure, with the exception of removing the fuel tank and radiator to get to the plugs. (this is a Hyosung GV250)

    Removing the tank was unexpectedly easy. The problem came when I got to the plugs. I tried to remove the cables connected to the spark plug gently, but that did not suffice. So, I pulled harder on the electrical cable. Suddenly it came away, and I thought I had broken the cable.

    The cable is connected to an "L" shaped adapter, and it appear the only electrical contact here is the end of the cable and a screw in the "L" adapter. After removing the cable, I was able to unscrew the adapter from the top of the sparkplug, and remove the sparkplug.

    I put a new sparkplug in, and screwed the "L" adapter back onto the new sparkplug. Then came the problem - how do I re-attach the cable (in a stiff rubber "condom") to the plastic "L" adapter?

    I'm not great when it comes to mechanical things, but I have a reasonable amount of experience with electrical and electronic circuits. The bare cable connecting to a screw does not seem like a reliable electrical connection to me.

    Because the cable is enclosed in the rubber condom, I can't be sure if it makes good electrical contact with the "L" adapter. Even if it wasn't enclosed in the rubber condom, I would never rely on on an unsecured contact connection between a bare cable and a screw in my own electrical work.

    So, what am I missing? Is this just stupidly designed, or am I being stupid?

    I have the full service manual for the bike, but it never mentions anything like this. It just says "remove the sparkplug" or "replace the sparkplug" but never mentions any of this crazy connector stuff.

    I have all the right tools, such as a torque wrench to ensure the plug is tightened correctly - but never anticipated that the electrical connections would be so strange.

    Thanks in advance for any help you netriders can offer.
  2. Success

    So, I gave in and called the service department.

    Seems what I was overlooking was that the ignition cap pulls off the spark plug, rather than screws off. After accidentally pulling the lead off the cap, I thought this was to allow the cap to turn and screw off. And the top of the spark plug looks like a screw thread.

    Also, the lead screws into the cap, and is supposed to remain attached. When it pulled off so easily, I thought it was designed that way.

    Still, even though the cap does screw on to the lead, it doesn't really seem like a very adequate way to make an electrical connection. Why don't they just put a proper plug and socket on the connector? It seems pretty dodgy to me, considering how it is a vital part of the ignition system.


    Anyway, I got it all back together, and the engine runs a little better now. I changed the plugs because it needed a lot of choke to run, and my dealer's service department said it shouldn't need any.

    It will now idle at a lower RPM without stalling, and with a little less choke. But even when it's warm, I still can't get it to keep idling without any choke. I'm trying to get to the next step - setting the idling speed. But I'm not sure how to get there, when I can't get it to run without choke.

    It's hard to get the RPMs to sit still, they fluctate quite a lot with the smallest changes to the choke. And it's strange how the choke works, with about half choke, it runs at about 2,000 RPM, but then as I close the choke, it revs higher and higher, up to about 4,500 RPM - but then I close the choke a little more, and the revs immediately drop and it stalls.

    Is this normal, or is there something funky going on with my engine?
  3. Re: Success

    It actually sounds like its running quite lean.
    I suggest getting a shop to have a look and having it fixed pronto.
    Using the choke richens the mixture. You wont be getting full power and using more fuel that you need to. You could also try fresh fuel from somewhere different if you dont fill up often. Run it on premium.
  4. Thanks.

    Can you recommend anyone for this kind of service? I was originally going to take it into Peter Steven for a full service, but they said it was probably the spark plugs, and my 4,000km service is still 1,200km away.

    They said it would cost around $300 for my 4,000km service, which seems like a lot. What should I expect to pay for just a check-up on this issue?

    I know dealers tend to be expensive for servicing. I want to eventually do most of it myself, but at least have the dealer stamp in my logbook up to the 4,000km service. But a general bike mechanic would be great to find for the smaller stuff, especially if s/he is willing to help me learn to service the bike for myself.
  5. Any bike shop should be able to get it going better.
    $300 would not be unreasonable. Bikes are not cheap to operate :)

    Having an honest relationship with your local shop goes a long way. Fing a good mechanic and stick with them. Most wouldnt mind if you did the basics but they hate fixing someone elses stuff ups.

    Your profile only says Melb so cant really recomment a shop. You could do better than the Elizabeth St dealers I reckon.
  6. Just to continue on this thread I thought I would ask a related question, is one spark plug any better than any other? Also when I was a kid we always changed our leads on our cars to "hi performance" blue ones, do they make a difference or was it for bling? If they do make a diff can you do this on a bike??

    Thanks guys. :grin: :grin:
  7. Re: Success

    It actually sounds like its running quite lean.[/quote]

    I agree, classic symptom and probably correct. But it could also be a symptom of the idle simply being too low. In any case, I would as a test increase the idle to see at what rpm it will idle without choke.