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1982 GS1100G - missing

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by duncan_bayne, Sep 16, 2012.

  1. Hi All,

    My GS100G (a.k.a. Maggie) is now running really well (when I remember to turn off the heated grips, and when I avoid running over nails). Except ...

    ... she misses. Not frequently, just the odd pause-shudder-continue at idle, and I think this may be related to a burbly-occasional-backfire noise on slight closed throttle or on the over-run.

    Anyone have any suggestions? Mototecnic has already tested the coils (OK) and replaced the plugs, HT leads and plug caps ... all to no avail. I'm running her on 98 octane unleaded but again, no difference.

    Back in the day I used to ride an RD350 ('74 model, wonderful bike ... had a fearful pedestrian warn me in all seriousness that my bike was on fire because of the smoke). I remember seeing a few aftermarket ignition systems for those ... has anyone heard of similar for an old GS? Or better yet, had any experience with them?

    TIA for any suggestions / war stories ...

  2. For a start, I'd ditch the 98 and go regular. Even if its the corn based stuff.
  3. It's unlikely to be the ignition black box (assuming it has one, rather than points, being an 82) as they usually function perfectly or not at all. The seeming last remaining ignition possibility is the pick-ups which, if I remember my Suzuki four anatomy correctly, will be on the end of the crank. They tend to deteriorate and can display intermittent faults, particularly when hot. It's difficult to pinpoint, though, without having a spare set of known good pick-ups to slap on. They can also be expensive if bought as motorcycle spares. However, Jaycar list a Hall Effect Sensor which may be a direct substitute (I know it is for my K100 but other bikes may vary) for $25 a pop. Two would be required for a four pot bike.

    If it's a carb fault instead, I'd be squinting suspiciously at the pilot jets, given that the fault manifests at idle.
  4. Dyna s ignition will solve any pickup problems. backfiring and odd burble may also be a vacuum leak, ie crack or hole in inlet manifolds,
    Possibly too lean in the pilot jets, will cause backfiring when backing off.
  5. I agree
  6. but......corn???