Having problems with my from discs warping etc. Have been told that this may be due to poor quality oil in the forks ?
I am looking t change the oil to a thicker / heavier grade sae 10 ?
any ideas if I can drain the forks or will I have to remove the forks to change the oil [/b]
Can’t say I’ve heard of that one before.
How do the forks behave? If they work fine it’d be a shame to lose that.
There’s an idea in the US that the Breva, Norge and Stelvio forks work better with 15W.
The Guzzi manual list 5-20 grade so there’s room for manoeuvre.
Hopefully you’ll get a more complete response soon 
Good luck
Steve
Are you sure that the rotors are warped? I had pulsating brakes on my Breva 1100 until I took to the rotor buttons. I twisted them back and forth by jamming a nail punch into them held in multigrips and squirted them with brake cleaner to free them up. Did this twice over a couple of weeks and never had a problem since.
No way that Fork Oil can affect the Discs, other than if it leaked out onto them!
As Mackers mentioned, quite often the ‘Bobbins’ in Floating Discs can get tight, either through corrosion, or a build-up of Brake Dust or other c##p.
Try giving them a clean, Brake or Carb Cleaner Spray is good, and try to ‘work’ them in some way to help free them off.
As for the Oil Weight question, I find Bike Forks tend to be a bit too ‘soft’ from the Factory, Damping-wise, and usually fit a grade or two heavier Oil.