Hi everyone, I have recently purchased a 84 Honda Shadow 700 with just 19k miles. Got it for my first project & bike, I only know a little about cars from working on my old Chevy and now my 8th gen Civic si. So on the day of inspection, owner claimed the battery won't charge, I had my car jumped the bike. It took a few try but we got it started and ran for least 20mins no problem, after purchased I had it sat inside for over a week until I tried starting up again. I had the battery charged up and connected with a jumper cable, It kept turning but won't ignite, after a few try it start to turn weak going on and off. So I stopped, thinking it could be out of fuel and I'm putting too much air in the engine. Another week passed, I moved it into my newly built shed. I poured 3/4 gallon of 93 and about an ounce of seafoam in, all lights came on fine on run position but it did nothing when I try to start. No turn and only hear a click sound from the rear after releasing the start button, that's also when I noticed my battery voltage gone down to about 10 after sitting for over a week. Had it charged up to 12.5V avg and tried again the next day, bike turned again but with no luck on igniting. It just kept turning for a few and stopped, then it gets weaker to not doing anything again. Tested the battery afterwards and find it dropped to about 11.5V, some people are telling me it's the relay, the starter or the rectifier. Any other ideas on what's causing this problem?
Here's a video of it starting to start