View Full Version : 1976 yamaha xs500 COIL PROBLEMS HELP

02-25-2016, 12:37 AM
So my coils burnt up on my bike , I didn't think much of it considering its a ancient pos and replaced em . Well those ones burnt up as well. Any one have any idea what would be wrong to cause this?

02-25-2016, 7:21 AM
Being a 76, I'd assume it it has point, I'm not very familiar with the 500s. If so, check the points adjustment, maybe you're running current to them way too often or way too high of voltage.

02-25-2016, 10:44 AM
I agree with checking charging system with voltmeter to ensure no overvoltage. When they were working did you get good spark? A shorted condenser can, rarely, kill a coil but then the bike wouldn't run since the short would be to ground.

BTW I don't leave ignition switches on without engine running on older bikes as if the points are closed current can flow through the coil and fry it.

These folks might know what to look for on a Yam that old. Different brands have different problems: https://yamahaclub.com/forums/