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General Minitrail Talk
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1981 Z50R issues - weak spark
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<blockquote data-quote="rgriggs" data-source="post: 171381" data-attributes="member: 11043"><p>Hi, I have a 1981 Z50R that my dad bought at a yard sale years ago. I rode it as a kid, then when I outgrew it, we parked it in our storage garage.</p><p></p><p>Now, about 25 years later, I'm hoping my kids can enjoy this bike as much as I did. We pulled it out of storage, put in some fresh gas, checked the oil, and gave it a couple kicks. It actually started! However, it required full choke to run. </p><p></p><p>I cleaned the carb carefully and tried again - still required full choke to run at all, and died often. I adjusted the jets, etc.</p><p></p><p>After a bit more tinkering it completely stopped and wouldn't hit, even with ether.</p><p></p><p>Checking the spark plug, the spark was very weak and sporadic. So I got a new spark plug and the spark was still very weak and it wouldn't hit.</p><p></p><p>I did all the following to no avail:</p><ul> <li data-xf-list-type="ul">Checked the points gap (about 0.012)</li> <li data-xf-list-type="ul">Cleaned the points with emery cloth</li> <li data-xf-list-type="ul">Removed the flywheel and tested continuity on all wires, as well as verifying that the run/stop switch works properly.</li> <li data-xf-list-type="ul">Tested continuity of primary and secondary ignition coils</li> <li data-xf-list-type="ul">Ensured the points were not stuck and work properly</li> </ul><p>Finally I removed the spark plug cap and held the bare wire near the frame. I got a very strong bright blue spark. I replaced the spark plug cap and tested again with the spark plug. I was now getting a strong spark at the plug.</p><p></p><p>Replacing the plug, I cranked the engine and it started (carb needs adjusting).</p><p></p><p>However it ran for just a couple minutes before dying and again the spark is very weak. Even removing the spark plug cap and testing the bare wire yields a weak/sporadic spark again. Won't even hit on ether.</p><p></p><p>Any ideas? Would it be best to replace the condenser? Or does this sound like an ignition coil issue?</p><p></p><p>The ignition coil spark winding measures 5k ohms with spark plug cap removed, and 10k ohms with cap installed.</p><p></p><p>I'd appreciate any suggestions on how to troubleshoot/fix this and get this great bike running again.</p><p></p><p>Also, anything else I should check/repair/replace to help avoid injury and/or damage to the bike after having been in storage for 25 years? </p><p></p><p>Thanks!</p></blockquote><p></p>
[QUOTE="rgriggs, post: 171381, member: 11043"] Hi, I have a 1981 Z50R that my dad bought at a yard sale years ago. I rode it as a kid, then when I outgrew it, we parked it in our storage garage. Now, about 25 years later, I'm hoping my kids can enjoy this bike as much as I did. We pulled it out of storage, put in some fresh gas, checked the oil, and gave it a couple kicks. It actually started! However, it required full choke to run. I cleaned the carb carefully and tried again - still required full choke to run at all, and died often. I adjusted the jets, etc. After a bit more tinkering it completely stopped and wouldn't hit, even with ether. Checking the spark plug, the spark was very weak and sporadic. So I got a new spark plug and the spark was still very weak and it wouldn't hit. I did all the following to no avail: [LIST] [*]Checked the points gap (about 0.012) [*]Cleaned the points with emery cloth [*]Removed the flywheel and tested continuity on all wires, as well as verifying that the run/stop switch works properly. [*]Tested continuity of primary and secondary ignition coils [*]Ensured the points were not stuck and work properly [/LIST] Finally I removed the spark plug cap and held the bare wire near the frame. I got a very strong bright blue spark. I replaced the spark plug cap and tested again with the spark plug. I was now getting a strong spark at the plug. Replacing the plug, I cranked the engine and it started (carb needs adjusting). However it ran for just a couple minutes before dying and again the spark is very weak. Even removing the spark plug cap and testing the bare wire yields a weak/sporadic spark again. Won't even hit on ether. Any ideas? Would it be best to replace the condenser? Or does this sound like an ignition coil issue? The ignition coil spark winding measures 5k ohms with spark plug cap removed, and 10k ohms with cap installed. I'd appreciate any suggestions on how to troubleshoot/fix this and get this great bike running again. Also, anything else I should check/repair/replace to help avoid injury and/or damage to the bike after having been in storage for 25 years? Thanks! [/QUOTE]
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