Before you wright off your discs try rubbing them down with scouring pad or grit paper. Do both sides of the disc well so the surface of each disc has been scratched up so to speak.
I had problem again recently after my rear disc was apparantly diagnosed as causing the problem. well before my 800 miles Wales trip a couple of weeks ago I cleaned my bike and noticed rusty marks on the rear disc. I used a rough scourer, satin pad, and resurfaced the rear disc both side. The pulsing dissapeared instantly.
I noticed on my trip also that the front brakes seemed to snatch at low speed when braking. I intend to buff them up also.
On another note! I have a worse pulsin problem on my RD350 when the discs warm up. Well I recently changed the chain + sprockets and whilst I was at it I removed the rear disc and polished it on my bench grinder/polishing machine with satin mops. This rescratched the surface. The bike seems to brake much better since then!
So, I wonder if this problem is also caused by glazed discs + pads, not just warped discs?
