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Hi folks,
I bought a bike about half restored. '78 XT500E. Many new parts, but the previous owner said he couldn't get it to spark. 

The coils look brand new, points and condenser as well. I haven't actually removed the flywheel to see the stator coils yet. 

Previous owner removed: battery, rectifier, and kill switch to run as a dirt bike only.  Key ignition switch is still intact. 

I unplugged the key ignition switch for these tests to eliminate that possibility, and I did a few tests. 

When I kick the bike, and hold the spark plug to the motor or other ground I get ZERO spark. 

When I remove the plug and cap, I got zapped when holding the wire and kicking.

When I take the Black/White wire leading to the coil and hold to a ground I get a noticeable blue and rhythmic spark. So power is making it to the coil. 

I got the following readings with my multimeter, though some of these jumped around a lot. 

Black wire from 4-wire stator loom to ground = 2.5ohm --- can't find spec
Primary Coil (Black/White wire male blade to ground) = 1.2 ohm -- spec is .75, so high...maybe too high?
Spark Plug Cap to ground = 11.73k ohm 
Spark Plug wire w/ NO cap to ground = 7.03k ohm - spec is 5.75K ohms, so again, high.  

Also, new plug, and even bought a new Emgo universal coil to test. Similar results, tho I think it’s got lower resistance than the other coil I’ve got which appears to be a newer after market unit. The gray one that it seems everyone has and sells for XT500. 

Also, attaching a pic of my points for reference in case something is majorly off there. 

Any help would be greatly appreciated.

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I thought of that too! I swapped one from my CB650 that I know works. No improvement. 

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Posted (edited)

If the frame has been powder coated there can be issues with grounding, where the coil mounts etc. + 1 on checking the points

Edited by DPete

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Ground is good, but yes the frame is painted. Scraped with a chisel, and buffed with 400 grit. 

The points are stil a big question mark. Leaving town this weekend, but gonna clean the points real well, and make sure I’m not grounding somewhere I’m not supposed to.

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if the points are clean and have the right gap, but the timing is out, you will get a weak spark or none at all. if the timing is in the right place but the condenser is faulty its the same. replace with a new one for piece of mind. (they dont last for ever)

stew

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