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1 cylinder cuts out

Discussion in 'Great Lakes U.S.' started by Stonesfarm, Mar 25, 2020.

  1. Stonesfarm

    Stonesfarm XS650 New Member

    I have a 1981 Special. 1 Cylinder will just randomly cut out while I'm riding then maybe a mile later will run on both cylinders again. But now it will only run on 1 cylinder.
  2. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Either a spark plug fouling/failing, or a carb that needs cleaning...
  3. thuban

    thuban Horse Scratcher Top Contributor

    How far do you have to go before it stats cutting out on that one? Or is it starting and running on one?
  4. Stonesfarm

    Stonesfarm XS650 New Member

    The last time it happened I had ridden about 50-60 miles. I had ridden and stopped about 3 times. After the last stop I rode about 3 miles and it cut out while I was riding. That lasted for about a mile, then it came back to life and started running on both cylinders until I got home. Now it starts and runs on 1 cylinder
  5. Bushyeyed1

    Bushyeyed1 Cafe Racer

    You seem to be losing spark imho. With the problem being intermittent I would check plug wire then ignition coil and then ignition wiring. Definitely check the plug too maybe it is on its last leg and barely making spark. Also comparing the color of the plug with the other side when it’s not cutting out will help in Determining if maybe your carb is running too rich or lean on that one side. If the cylinder isn’t firing though the plug will be wet with fuel so it will need to have been running prior to shutting it off to get a legit reading. You could swap plug wires since the coil fires at the same time and see if it switches side.
    TwoManyXS1Bs, Mailman and thuban like this.
  6. wildav

    wildav XS650 Enthusiast

    Used to be an intermittent problem with my bike Sometimes a points issue , other times a carb blivet. Stuck floats twice which was easily detected by gas pouring from breather out on the crankcase. The points usually included some backfiring. Pamco iggy fixed that.
  7. thuban

    thuban Horse Scratcher Top Contributor

    I'm with Bushy. I'd check Fire first. Mine was doing the exact same thing. When it ran it would run great and then start banging out on one. One + wire feeds both of the coils so you know you have power right before the power splits to right and left coil. Pull the tank. ( Check it for water while your at it) Double check the connections, plug-ins at both coils and wire to points. Mine were loose in there connections. As a stop gap measure, I cleaned and crimped them just a bit then zip tied the bundle to the frame to keep them from flopping. (It's on my list to replace the plugs with high quality model aircraft plugs)
  8. Mailman

    Mailman Hardly a Guru Top Contributor

    All good suggestions regarding going through all of your connections. I had a cylinder that started cutting out once and as I was going through things, I tugged on my spark plug wires and on the cylinder that had been cutting out, the wire pulled right out of the spark plug cap with almost no effort. If you’ve never had your spark plug wires apart , I’ll tell you that in the center of the cap ( and the same for the coils ) is a screw like thing that you screw your spark plug wire into. They get burnt and corroded, you can pull things apart and shine that connection up with a wire brush Dremel and re make your connections. You might have to snip off a little of the burnt spark plug wire, or go crazy and buy some new ones if they look bad. Good luck!
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