Ducati Monster Forum

Moto Board => Tech => Topic started by: COP TZR on February 07, 2013, 07:45:48 PM

Title: "pee" cup reservoirs, using the small one for front brake?
Post by: COP TZR on February 07, 2013, 07:45:48 PM
Can anyone confirm if its safe to use the smaller pee cup (clutch reservoir) for a front brake reservoir?  I've seen many of the Radical Ducati bikes using them.  Other than aesthetically being more discreet, are there any pros or cons to this?

thanks
Title: Re: "pee" cup reservoirs, using the small one for front brake?
Post by: bigiain on February 07, 2013, 08:18:16 PM
The downside is that the smaller cups don't have enough "spare" volume to ensure that you won't suck air onto the master as your front pads wear down. As the friction material wears, the space needs to be "filled up" with brake fluid behind the caliper pistons. By the time you've worn the whole 1/4" or so of useable material from your pads, you need to put more fluid into the calipers than the small cups hold.

So long as you're comfortable with keeping an eye on the fluid level, and topping it up as the pads wear, it'll work fine.

Keep in mind, the consequences of inattention could be very high - grabbing a hand full of throttle grip when you really want front brakes could be a _really_ bad thing.

I'd probably feel OK doing it on my own bike, but not if I planned on lending it to other people regularly - people who I'd most likely forget to mention "oh yeah, and check the front brake fluid level every now and then, it might need topping up..."

big
Title: Re: "pee" cup reservoirs, using the small one for front brake?
Post by: Speeddog on February 07, 2013, 08:46:04 PM
I've had my bike set up that way for a *long* time.
No issues.

As Iain said, keep an eye on the level.
Title: Re: "pee" cup reservoirs, using the small one for front brake?
Post by: SpikeC on February 09, 2013, 06:26:26 PM
 As the reservoir is pretty much in your line of sight, I would think that monitoring it would be fairly easy.
Title: Re: "pee" cup reservoirs, using the small one for front brake?
Post by: DucatiBastard on February 11, 2013, 07:03:14 PM
What's the consensus on using just a bit of Tygon tubing or similar? I've seen it used on the rear brake on a modded  monster or two.  I've also seen it on one custom bike, its been posted here, I think it started as a Yam Virago? Anybody remember that bike?

It looked clean as hell, made me a bit nervous.  Although the tubing is clear, shouldn't be difficult to watch...

-edit-

here it is
http://www.bikeexif.com/wp-content/uploads/2012/06/yamaha-virago-xv750-2.jpg (http://www.bikeexif.com/wp-content/uploads/2012/06/yamaha-virago-xv750-2.jpg)
Title: Re: "pee" cup reservoirs, using the small one for front brake?
Post by: COP TZR on February 11, 2013, 09:16:32 PM
Quote from: DucatiBastard on February 11, 2013, 07:03:14 PM
What's the consensus on using just a bit of Tygon tubing or similar? I've seen it used on the rear brake on a modded  monster or two.  I've also seen it on one custom bike, its been posted here, I think it started as a Yam Virago? Anybody remember that bike?

It looked clean as hell, made me a bit nervous.  Although the tubing is clear, shouldn't be difficult to watch...

-edit-

here it is
http://www.bikeexif.com/wp-content/uploads/2012/06/yamaha-virago-xv750-2.jpg (http://www.bikeexif.com/wp-content/uploads/2012/06/yamaha-virago-xv750-2.jpg)

I thought about that for my rear brake as well.  What do you cap it with?  Must be a pain in the arse to fill & bleed.
Title: Re: "pee" cup reservoirs, using the small one for front brake?
Post by: He Man on February 11, 2013, 09:24:10 PM
no bs. looks like a m5 bolt lol.

as long as it doenst go empty you are good to go.

the issue is the margin for error.  if you can handle the margin of error then go for it.
Title: Re: "pee" cup reservoirs, using the small one for front brake?
Post by: JohnEE on February 12, 2013, 04:46:26 AM
(http://www.kurveygirl.com/tygon2075/Tygon%20-%20Rear%20MC.jpg)

The cap used on Kurvey girl is a honda part, follow the link for more info (http://kurveygirl.com/shop/product_info.php?cPath=106&products_id=279)
Title: Re: "pee" cup reservoirs, using the small one for front brake?
Post by: graydo on February 14, 2013, 09:14:16 AM
I understood brake fluid to be hygroscopic so the cap would want to be pretty good to keep the moisture out, too much moisture absorbed and the boiling points drops significantly, not a problem with a clutch but a brake?
How about using the pee cup and the clear tubing? at least if the fluid drops out of the cup you can still see if there is some in the line and be confident to ride out for more fluid? easier to fill as well.
Title: Re: "pee" cup reservoirs, using the small one for front brake?
Post by: ollie on February 15, 2013, 03:41:22 PM
Quote from: Speeddog on February 07, 2013, 08:46:04 PM
I've had my bike set up that way for a *long* time.
No issues.

As Iain said, keep an eye on the level.

This could be a good option for me, I'm in the process of lowering the gauges and headlight on my 620, and icve got issues with the double banjo bolt off the master cylinder not clearing the gauges due to my clip on setup.
Is it simply a matter of finding a stock clutch reservoir and plugging it into the system - will there be any issues with it trying to get it to work on the 620 brakes ?
Title: Re: "pee" cup reservoirs, using the small one for front brake?
Post by: Speeddog on February 15, 2013, 03:54:12 PM
IIRC, you'll have to re-bend the reservoir bracket.
But it's been a long time since I've done it, and I don't have a bike with a stock large-reservoir on it at hand now.

Other than that, plug it in, fill it, and don't ignore it for thousands of miles.