A little electrical help needed - Motorcycle-Journal Forums

jone30 · 05-19-2007, 04:11 PM

I'm new here. How's it going?

So, I work on BMW's/Volvo's/some Merc's for a living. My boss bought a really cool old school bike at an auction a couple of months ago. It's a 1988 Yamaha FZ 600. It didn't want to run when we got it, cleaned out the carbs, put new gas in it, threw a new battery in, and we rode it around the neighborhood next to our shop every saturday for a while. I went to take it down the road to put some gas in it and before I was able to pull out of the shop, it died. We had to jump it to get it to run. I pulled it out today to try and see what the problem was after letting it sit up for a few weeks. Checked the battery, it is holding a good 11.07 v according to my multi. Jumped it, checked the volatage. Turns out it is only putting out about 10 v or so at idle and quickly killing the battery without the jump box. If you rev it a little, it will jump up and provide a little more voltage and allow the headlights to become brighter.
Now, I don't know that much about working on bikes other than being able to work on the carbs. I know there is no actual alternator to do the charging. What should I look at next? Is there a voltage regulator in there somewhere, like there is in an alternator? Any help would be greatly appreciated, I would love to be able to ride this bike on a nice sunny, cool weathered day, like today.

Thanks,
Jon