Motorcycle Repair: 1981 yamaha special electrical problem, electrical problem, electrical component

Question
how can i tell if my rotor is bad?i have already looked for shorts and cant find anything;if i unhook my top brushwire the thing will startup but if i hookup the top brushwire as soon as i turn the key on it blows the 20amp fuse right away;so i put foil around the fuse and when i turn the switch on the brownwire coming from the stator hookup starts to smoke i think the brown wire is the top brush wire.do you know anything that will help me if so please give me some suggestions i have already talked to someother guy and did a lot of test with a multimeter but wasnt really sure how to read the thing im just a backyard mech thank you paintdoctor

Answer
Hi Harry,

If I had your email as requested, I could return electrical test information.

I recommend buying the service manual for your MC. It will explain all the testing procedures for every electrical component on the MC. It will pay for itself with the first repair.

I cannot diagnose the problem without seeing the MC and making some checks. Do not put any object or materials in place of a fuse. This may damage the whole circuit, including electronics (CDI). They are very expensive to replace.

Send your email to: mshively1@woh.rr.com

Respectfully,
Mark Shively