Barn find spark issues

Don

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Sorry if this is covered, but I have been trying to find a solution to getting my first bike firing. If it’s been covered, please point me to the right direction. Anyway, my friend found a couple of old bikes in a barn and got me the 1982 xs400 with 18,181 kms on it. It had been sitting for over 10 years, low compression on the one cylinder, clogged carbs, and a jammed rear brake. We got the cylinders honed, and new rings in it, now it has a really weird sparking issue. One side sparks almost constantly, the other side seems to spark only when I let go of the starter button. Sometimes it’ll spark while it turns over, but rarely. Here’s the things I’ve done……switched the coils (does the same with each one) got a new rectifier (didn’t change) gone through the whole bike for ground fault (found a couple not connected, didn’t change) checked the points (one was a little dirty, didn’t change) checked the starter (cleaned it up and checked the polarity, all the wires are fine and didn’t change) the only thing that I haven’t checked was to see if the timing was out, but I assumed it was still fine from when I put it back together. I’m at the end of my rope. Has anyone had a problem like this and solved it?!?!?
 
Yes, the constant sparking is due to grounding issues in that circular timing plate where you adjust the points.

You'll need to clean all of that up, possibly replace the plate/points/gaps parts and see if you can isolate the grounding issues
 
I thought the 82's had electronic ignition, but if it still has points you really want to make sure they are cleaned and gapped correctly. Hit the contact points with a little fine sand paper. I just fold a little chunk of 400 grit in half, rotate the engine until the points are closed then open them, slide the sand paper in and tug the paper in and out a dozen or so times and check them. Then clean them with a paper towel soaked in alcohol in the same manner. Setting the static timing is also very easy with points, it just requires a lot of patience to get it perfect. This guy's video on setting using an old brake light bulb and some wires is pretty good, though some camera angles are not great. Setting the Timing on a Yamaha 1978 XS-400E - YouTube. Also, it's possible your condensers are shot and not absorbing the voltage spikes anymore. This video will give you an easy test for that as well. How to test a Condenser or Capacitor - YouTube. Good luck and let us know what you find.
 
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