Ducati Monster Motorcycle Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
76 Posts
Discussion Starter #1
Today was my first ride on my new to me 2015 Monster 1200S.

I bought this bike from Copart last July as a salvage bike with 6900 miles. It had been dropped on the RHS, the RH footrest mounting casting, lower triple tree and tank were the main damage. Not too serious really!

After riding for a short distance <3 miles I felt a fair amount of drag and the bike would slow un-naturally quickly on no throttle. I thought at first it was the rear brake, but on closer examination found it was the front. I let the bike sit for a few hours and prepared for a second short ride. When I pulled the front brake lever it came almost all the way to the handle bar.

First clue?

On the second ride the same thing happened, although at one point the drag seemed to reduce a little. When I got home the front discs were quite hot.

During the rebuild the entire front end of the bike, from the steering head forward was off the bike and rebuilt, but the front brake hydraulics were always intact, the same pads as came off the bike were re-used, master cylinder was never opened etc.

So what could be causing this brake drag? The front brakes work great! Almost too good!! But it seems that the brakes are staying on. I guess it could be hydraulic or mechanical.

I'm looking for suggestions and any help that may help me fix this so I can ride this amazing machine. Here is my list of possibilities:

Rotors not central in the calipers.
Piston stuck.
Master cylinder stuck.
Kinked hydraulic line.
Return flow blocked.
Too much brake fluid. Checked OK but removed a little.

I'm going to take a good look at this in the morning but would really appreciate any suggestions, experience etc

Many thanks,

Ian
SoCal
 

Attachments

·
Registered
Joined
·
76 Posts
Discussion Starter #2
One more idea . . .

Moisture in the brake fluid. The bike has sat for 8 months, although I am in SoCal so not the wettest climate!

I'll bleed all hydraulic systems with fresh fluid, just for good measure . .

Ian
SoCal
 

·
Registered
Joined
·
292 Posts
Sounds like fluid is not returning into the master cylinder...not familiar with your brakes...but the pushrod into the master cylinder needs free play...as the fluid heats it expands and will eventually lock the pads to the rotor and catapult you over the bars...very dangerous situation!!!

Opposite of the pushrod there may be apear to be a screw that takes a flat head...if thightend fluid can not return to the reservoir...screw it all the way in and back it out 1/4 turn
 

·
Registered
Joined
·
76 Posts
Discussion Starter #4
Hi,

Thanks for the suggestion. My first thought was something along those lines, but there is some information that suggests to me that this is probably not the case.

When the bike was delivered it was to a friends business, 5 miles from my home. I rode the bike, damaged, to my home and had no problems with the brakes. The distance was double to my ride yesterday when the brake problem showed up. During the rebuild the braking system was not disturbed, except for the calipers being unbolted from the forks, the master cylinder was not removed or worked on in any way.

The fact that when the system has cooled down it needs to be given one full brake lever pump to get the lever solid again leads me to think that it is probably a fluid issue, although not returning to the master cylinder/reservoir, or returning too slowly, is also a strong possibility, although with nothing changed its difficult to understand why.

I appreciate any further thoughts.

Ian
SoCal
 

·
Registered
Joined
·
292 Posts
Absolutely check the adjustment screw I discribed before you ride again... during disassembly it can easily be mistaken and screwed tight....it maybe the old fluid that allowed you to even use it in the first place...you remove the air and the fluid doesn't return you WILL crash...if the adjustment is as it's suppose to be make sure it's not blocked with debris
 

·
Registered
Joined
·
76 Posts
Discussion Starter #6
I will absolutely check the master cylinder, including the pushrod.

I'm missing something here so I need to go back to basics and check everything!

Thanks,

Ian
SoCal
 

·
Registered
Joined
·
76 Posts
Discussion Starter #8
I just checked, my bike is subject to the recall, I'll call on Monday to find out more.

I looked at the master cylinder to see about a pushrod that can be adjusted. The Picture below shows the arrangement on the 1200S. I've backed of the small adjuster nut a 1/2 turn; we'll see if it makes any difference.

Keep the ideas coming!

Ian
Socal
 

Attachments

·
Registered
Joined
·
76 Posts
Discussion Starter #9
Good news to report!

Breaking all the rules, I made two change at the same time! I backed of the pushrod in the front master cylinder and bled the whole system with fresh fluid, and my problem seem to be solved. I went for a very short ride, only 5 miles, but twice the distance that the problem occurred before, and had no issues at all.. I'll try a longer ride next weekend or maybe one evening if I'm home at a decent hour! I also bled the clutch system which seemed to have a strange take up point and the fluid was very grey- massive improvement! I've never had a bike where the M/C had a bleed nipple on it, but this is where I got most of the air on both the brake and Clutch.

BTW. I used Motul RBF 600 Racing Brake Fluid.

Thanks for the help and advice; I report back with any new issues!

Ian
Socal
 

·
Registered
Joined
·
532 Posts
@ianashdown
Brembo has a brake recall. Check to see if your bike's VIN is on the list.
This is Brian being glad that he has a 2014! The rest of the bike may fall apart because it's the first year but damn, my Brembo's are all good! :devil

Ian, Was the fluid discolored brown or whatever? If you had enough moisture in the system maybe you had a half hydraulic and half pneumatic system when the water evaporated from the heat! :smile
 

·
Registered
Joined
·
76 Posts
Discussion Starter #11
Hi,

I didn't put the original fluid in the bike so it's difficult to say how discolored it had become, but it did look quite dark to me. Actually darker in the M/C than the caliper. The Clutch fluid was also quite dark. So I don't think replacing it was a bad thing to do. The Motul I replaced it with was quite a bit lighter in color.

The bike sat outside at the salvage yard for a few weeks so it's possible it got rained on and there was enough moisture in the air to contaminate the fluid. I'd hope it wasn't that easy but . . .

As I said, by breaking the rules and making two changes at once, I now don't know which fixed the problem, but nothing was disturbed mechanically during the rebuild so my money's on the fluid!

Ian
SoCal
 

·
Registered
Joined
·
76 Posts
Discussion Starter #12
Hi,
I went for my first proper ride today; beautiful 76 degree sunny day in SoCal, only 20 miles but I had a chance to stretch its legs a little!

The brake problems seem to be resolved and all is well in that department. The clutch needs bleeding again, but it was useable with a little getting used to. The lower seat position is much better for me at 5'10". No other problems showed up si guess I'm good to take on a decent ride, once I've been through the DMV, CHP etc!

It's been about a year since I sold my 696 so I was definitely a little rusty, but the bike felt great, solid and stable right from the beginning. The bike is un-godly quick, but very happy to cruise up Ortega Hwy at 85-ish. I felt the bike felt more 'under me' even after a few minutes than my 696 did after years of ownership! Slow speed throttle response is a bit snappy, but maybe a 14T sprocket will help that.

It'll take a little while to get all the reflexes and timing so its second nature but I think this is going to be a beautiful relationship!

Ian
SoCal
 

·
Registered
Joined
·
76 Posts
Discussion Starter #13
Just a quick update.

I read that there was a Master Cylinder Piston recall on various Ducati and found out that my M1200S was included in the recall. I finally got around to getting to a Newport Ducati (Great guys!) to hav3 the piston replaced yesterday. The difference is huge! I wouldn’t have believed it could make such a difference. The brakes are enormously powerful on this bike, but now the lever has precision and feel.

If your bike is part of the recall, and you haven’t made the switch yet, I highly recommend that you do so.

Ian
SoCal
 
1 - 13 of 13 Posts
Top