Question
Colorado High Back Cou
It was running great, always started on the first try, and ran well at anywhere from 5,000ft to over 11,000ft elevation. Now it will not start. Has compression. Has new battery, getting fuel to carb, spark plug cleaned and gap set @ 0.6mm, points gap set @ 0.35mm with the flywheel F mark aligned with the mark nub. Spark plug wire tested OK. Valve gap set(cold)@ 0.05mm. The ignition switch checked out OK, and the lights and horn work. Just before quitting, it was missing and back fired a few times, so I shut it down, now it will not start. I tried spraying a little gas directly into the carb, but that did not work. Only a thought, but I do not know how or if you can test the alternator (rotor & stator) assembly system. Any suggestions or help would be greatly appreciated, thank!
AnswerGary, "has compression" is a relative term. Best to test it directly. Should see about 140-150psi or so, at least. Honda's specification is 171 psi. Some of the models, back then, had little flapper doors on the carb's choke plate that were spring-loaded. After awhile, the springs failed, allowing the doors to flap back and forth rapidly, usually resulting in door failure and ingestion into the engine. Depending on whether it was the spring or the door, the compression would obviously be affected. So, just to be safe, check the choke plate mechanism and the compression first.
Beyond that, judging from the missing/backfire symptoms, you may have a failed condenser or coil, which are bolted together up inside the frame. Failed condensers reveal themselves when you observe the points arcing excessively with the key on cranking/running. Check the primary winding resistance on the coil with an ohm meter, after you disconnect the two small wires. Points ignition coils usually have about 4 ohms resistance values.
IF you are kicking it over a lot in the attempts to start the engine, you can easily fuel-foul the plug, which makes starting even more difficult when everything else is working correctly. Try a fresh plug and check for consistent spark at the gap. If erratic, then likely the condenser is bad and/or the coil is failing. Check for voltage at the points, which should be fairly close to battery voltage. Sometimes the KILL switch contacts can get corroded or the wire connections get shorted or loose. Check all electrical connections AND grounding points for clean and tight fitting.
The ignition system is battery-powered, so the alternator isn't a factor unless it is allowing the battery to go flat. Once you get it running, check output for around 7.5 volts.
FYI wiring diagrams are available here: http://oldmanhonda.com/MC/WiringDiagrams/MCwiring.php
Bill Silver
