Motorcycle Repair: 1981 yamaha 400 electrical, amp fuse, yamaha 400

Question
on my daughters 1981 Yamaha xs400 special starter bike, the main and ignition fuse keep blowing. i cannot find a short. can you help me solve this dilemma? it's a very well kept bike other than this problem. thank you for your time.

Answer
The first thing I would check is the fuse the right amp. Or has someone put the wrong fuse in before you got the bike.It may be that the fuse is really to small for the application.Check with your dealer for the proper amp fuse to use.If it is the right fuse get back to me and we will try some test. Jerry