My bike is an '01 M900 Dark which has cup-style reservoirs and gold master cylinders with the four-way adjustable levels. AFAIK the 900 Darks came with coffin-style master cylinders, so I'm guessing one of the previous owner upgraded these.
When I pulled her out of the garage this year to ride, the brake master was a little spongy. It got worse over a few weeks, but slowly so I didn't notice it. I checked the calipers and found no air bubbles, so I bled the master cylinder and it seemed better.
After a few weeks it got spongy again and I bled it again, this time more carefully. It was rock solid after this for a few weeks and then again it got spongy. I'm on bleed #3 now and it's about to need another. I'm thinking the master needs to be replaced.
Sorry for the long winded story - wanted to give an accurate background.
My questions:
1) Is it possible that the master on the bike is incorrectly sized and therefore air is getting into the system somehow? I'm wondering if a PO added it and bought the wrong one.
2) I've seen a few different sizes of the gold masters. How do I check which I have?
3) Assuming it's the master, should I just buy a new one, or is there a rebuild kit option?
Thanks in advance folks!
1) Yes, possible it's the wrong size, but it won't suck air because of that.
2) They're stamped, I don't have the 'code' at hand.
3) No rebuild kits that I know of.
Thanks Speeddog. I guess step 1 is checking for the stamp.
How do I know which size I need? Are the calipers stamped accordingly as well? Ideally I'd like to verify I have the proper size to begin with before I replace it. Looks like yoyodyne has masters in all shapes and sizes at somewhat reasonable prices.
I don't remember the whole code as it is stamped on the cylinder, but it is a 16 mm. bore and, AFIAK, in '01 all 900s came with pee cup masters. If rebuild kits are still available http://www.yoyodyneti.com (http://www.yoyodyneti.com) will have them. If not, a new master is not terribly expensive, or you might want to upgrade to a radial master. Call and speak to Fred for fitment and advice.
I have an 01 M900S and have the cup style. I think those were stock on all 900's that year. But don't know for sure
Thanks guys. I know Ducati likes to mix things up a bit with model switchovers and the '01s are the first injected models so it isn't surprising that they'd have the cup-style.
I'm tempted to go with a radial master, but then I'd need to buy a radial clutch, and radial calipers, and then new forks . . . it's a slippery slope. :)
Thanks again!