What other more powerful calipers fit the XS650 ?

[OakBehringer]

I could be confused but because we're talking about bores at two different ends of the system, increasing master cylinder bore increases pressure at the caliper because it moves more brake fluid-- I think.

A smaller bore at the caliper would increase pressure at the caliper but it would also reduce braking forces as less fluid is being moved.

And please, if I'm confused, somebody school me.

Smaller MC bore makes your brakes feel stronger. I just switched to an 11mm MC (stock 81 caliper) and I can now one finger brake. SS brake line really helps, too.

Or you can spend a shitload on other full-on brake upgrades. They'll look cooler on stock. But the stock caliper is a fine piece of machinery. Just gotta get a smaller MC.

 

[XSLeo]

As you pull the lever you exert say 50 lbs of force on the lever. The lever has a say 3-1 ratio. This increases the pressure three times where it pushes the plunger. So 50 x 3 is 150 lbs. On the plunger. The plunger bore is say 14 mm. Now the math gets tougher. Area is Pi x radius squared. So 7 mm x 7mm is 49 x 3.14 = 153.86 mm squared . Divide the 150 by 153.86 = .97 lbs per mm squared.
Now lets use a 10 mm bore. 5 x 5 is 25 x 3.14 = 78.5. 150 devided by 78.5 = 1.9 lbs per mm squared. So as you can see the smaller bore gives more line pressure. More line pressure gives the caliper a stronger squeeze.
These numbers are just an example, the real numbers I don't know and to lazy to go check. But the relationship is the same. Decrease bore size increases the pressure.
Leo

 

[ReycleBill]

As you pull the lever you exert say 50 lbs of force on the lever. The lever has a say 3-1 ratio. This increases the pressure three times where it pushes the plunger. So 50 x 3 is 150 lbs. On the plunger. The plunger bore is say 14 mm. Now the math gets tougher. Area is Pi x radius squared. So 7 mm x 7mm is 49 x 3.14 = 153.86 mm squared . Divide the 150 by 153.86 = .97 lbs per mm squared.
Now lets use a 10 mm bore. 5 x 5 is 25 x 3.14 = 78.5. 150 devided by 78.5 = 1.9 lbs per mm squared. So as you can see the smaller bore gives more line pressure. More line pressure gives the caliper a stronger squeeze.
These numbers are just an example, the real numbers I don't know and to lazy to go check. But the relationship is the same. Decrease bore size increases the pressure.
Leo

Decreased MC bore size increases the pressure at the MC but it also results in less fluid being moved to the caliper. Could it be the positive results of using smaller MC bores has more to do with the levers that accompany the smaller MCs than the actual bore of the MC? A change in leverage would result in a change in stroke, whereby a longer stroke increases pressure and stopping power as it moves more fluid.

 

[retiredgentleman]

ok so maybe i missed this in the thread, but where did you get the bracket to do the rear setup? This swap looks awesome! The only concern i have, other than i need to put SS lines, is that stock rotors are heavy, even if you drill them. Any thoughts on other aftermarket rotors that would still fit but would still cut theweight down? maybe with other rotors, you wouldnt need to file down the caliper to clear xs650 rotor?

Just my two cents. Best of luck. Like to know what you find out when you get yours going. Keep us posted!

For the adapter brackets, I bought some 3/8" aluminum and custom designed them to fit. I used cardboard to make a template and then used the template to cut the aluminum.

Yes, the stock disks are 7 mm, but there are 5 mm disks available from other Yamaha bikes. I believe 5twins is using a 5 mm disk. Some of the Ducati disks, which are only 3 or 4 mm, have the same bolts pattern, so they are easy to use.

I just got out for a short 20 kms test ride, and I'm really pleased with the Brembo calipers. My stock disks and stock master cylinders work great. The front caliper gives much more powerful braking as compared to the stock caliper. The stock caliper needed 4 fingers, but the Brembo only needs 2 fingers. The rear caliper has a good braking feel as well.

 

[XSLeo]

I don't think the lever ratios will change much when the bore size changes. The distance from thre bore center line to the lever and the length of the lever are pretty much set, can't change them much.
The amount of fluid needed isn't much, so any change in volume won't change pressure.
Pressure is a force applied to a certain area. To chagne pessure you have to change the force or the area it is applied to.
To change the force you need stronger hands. That's not easy for most people. Much easier to change the area the force is appiled to. This is done by changing bore size.
Leo

 

[DirtyErnie]

re: smaller master cylinder: You get more pressure from a smaller master cylinder, so more breaking force at the caliper. Smaller master cylinder has to travel farther to supply the same fluid as a larger cylinder, so the brake lever will have a longer travel between initial grip and wheel lock-up. In the real world we call that more 'feel'

Small cylinder has better brake feel and better stopping performance. I second the 11mm master cylinder with the stock 38mm calipers, mine's awesome. Upgrading your brake pads is another worthwhile venture.

RG, that is an awesome set-up, hope it's as HAWT on the road as it is to look at.

 

[ReycleBill]

Okay, so I'm very confused but for the life of me I'm unable to grasp how forcing less fluid into a brake line makes for higher pressures at the caliper. And with everything else being equal would a smaller MC bore not move less fluid into the brake line?

 

[turn left]

(...) stock rotors are heavy, even if you drill them. Any thoughts on other aftermarket rotors that would still fit but would still cut the weight down?

http://www.xs650.com/forum/showpost.php?p=667&postcount=13

 

[scott s]

For the 34mm forks, with the caliper on the front of the fork, which Brembo caliper should I look for? RH or LH side? Does it matter?
The pic of blackbetty's bike looks like he's using a LH caliper on the RH side with 34mm forks.....correct?

 

[scott s]

Or, upon closer examintaion, are the calipers reversible? I see some pics where it looks like they are the same, LH or RH and can be reversed.

What bikes, other than Ducatis, did they come on?

 

[turn left]

@scott_s if you're going the Brembo route, Pandemonium has a few sitting around their shop from test fitting their new brackets. They sold me one in excellent condition for $75 + bracket and hardware for $39. Everything bolted up. Best thing to do is call them as the calipers are not advertised in their web store.

 

[jd750ace]

RE: pressure- If you have a 6 foot long stick with a pivot at one end sticking up at a 45 degree angle, with a "foot" extending to the ground 1 foot from the pivot point, are you going to develop more PSI if that foot is 1 inch wide, or 6 inches wide? The answer is, the leverage is the same, but the smaller foot will develop more pressure per square inch, as the same leverage is applied to a smaller area. Make any sense? Volume of the caliper is easiest consumed with a big master cylinder. a smaller master may require more travel, but you have more peak pressure, because the pressure is even throughout. A large master may bite faster, but peak pressure will always be higher with a smaller cylinder, given the same lever ratio.

 

[dachillman]

Thanks very much turnleft for the list of rotors. I think i will definetly be getting this setup for the front, but im going with dual disks. Ill post pics soon of the upgrade. Thanks for all the help. I think im going to leave the stock MS for now and get her running and see how she goes. Wont be a while before i get that far but well see.

I assume the rear rotors are the same size and mounts? ill measure when i get home. Cheers!!

 

[XSLeo]

recyclebill, yes a smaller caliper will move less fluid. The amount of fluid moved has little to do with pressure.
Liquids can't be compressed. So in a sealed system no matter how long the stroke of the M/C once the pressure pushes all the movable parts as far as they can travel the pressure can only reach a certain amount. Once this pressure is achieved you won't pull the lever any farther.
Your hand strength is the limiting factor in the pressure in the system. The only way to get more force on the piston is lever ratios.
Most levers are about the same length and are mounted about the same distance from the bore centerline. These lengths and distances limit the ratio.
With most levers you can only produce so much force on the M/C piston.
With these restrictions the only way to change pressure in the system is to alter the M/C bore size.
The calipers need a certain amount of fluid to work. The stock M/C moves this amount with a certain amount of lever travel. A smaller M/C moves the same amount of fluid but uses a longer lever travel to move this amount of fluid.
The caliper needs a certain amount of pressure. The stock M/C can deliver a certain amount of pressure.
The smaller M/C creates the same pressure with less force applied to the lever.
The smaller M/C may use a bit more lever travel and stroke to move the required volume and create the required pressure, but this increases the power and feel of the brakes.
I'd like to suggest a web site that could explain how hydralics work in a brake application, but I don't have any. Maybe a search will help you understand better.
Leo

 

[ReycleBill]

The smaller M/C may use a bit more lever travel and stroke to move the required volume and create the required pressure, but this increases the power and feel of the brakes.

Leo

I think that explains it well enough. Thanks

 

[retiredgentleman]

ok so maybe i missed this in the thread, but where did you get the bracket to do the rear setup? This swap looks awesome! The only concern i have, other than i need to put SS lines, is that stock rotors are heavy, even if you drill them. Any thoughts on other aftermarket rotors that would still fit but would still cut theweight down? maybe with other rotors, you wouldnt need to file down the caliper to clear xs650 rotor?

Just my two cents. Best of luck. Like to know what you find out when you get yours going. Keep us posted!

I'm a very hands on type of guy. I bought some 3/8" aluminum flat stock, and then made a cardboard template that would mount the caliper on the rear axle. Made a cardboard template for the front caliper as well. I then used the template to mark the aluminum flat stock.

I used my drill press to a series of small holes following the template lines. Follow that with cutting along the holes using a hack saw. A coarse file cleans up the edges. Drill some mounting holes, and that's it.

Yes, the stock rotors are 7 mm and they are heavy. I saw no reason to spend more money on thinner rotors, so some grinding on the calipers does the trick for me. I believe that Ducati rotors are a direct bolt on to out wheels, and they can be found in 4 mm or maybe even 3 mm thickness. Its your choice..............pay more money for thinner, lighter rotors or modify the caliper and be cheap (frugal) like me.

My opinion of these calipers............... just a huge improvement in braking. If you think safety is important while biking then these calipers are the way to go.

 

[DeftQuiver]

This weekend I plan to throw on a 10mm master cylinder and pads... I'll post on how the stock caliper fairs with the smaller MC as soon as I know. I have a feeling I'll just find out that the braking is way better, but my front suspension sucks

 

[ReycleBill]

List of Bikes with 320mm rotors and 80mm 6 bolt circle (may offset differently.) I think! Please verify before you buy.

APRILIA AF 1 FUTURA 125 1990-1992
APRILIA RS 125 2006-2008
APRILIA RS EXTREMA REPLICA 125 1993-2005
APRILIA PEGASO FACTORY 660 2005-2007
APRILIA PEGASO STRADA 660 2005-2007
APRILIA PEGASO TRAIL 660 2005-2007
APRILIA SHIVER 750 2007-2008
APRILIA MANA 850 2007-2008
APRILIA RSV - SP 1000 1998-2000
APRILIA RSV - SP 1000 2001-2004
APRILIA RSV R 1000 1998-2000
APRILIA RSV R 1000 2001-2004
APRILIA RSV R FACTORY 1000 2004-2008
APRILIA SL FALCO / R 1000 2000-2004
APRILIA TUONO R 1000 2006-2007
APRILIA TUONO R FACTORY 1000 2006-2008
BENELLI TORNADO LE 900 2002-2003
BENELLI TORNADO RS 900 2004-2005
BENELLI TORNADO TRE 900 2003
BENELLI TNT CAFE' RACER 1130 2006-2008
BENELLI TNT SPORT 1130 2006
BENELLI TNT TITANIUM 1130 2005-2006
BENELLI TORNADO TRE 1130 2007-2008
BIMOTA V-DUE 500 1997>
BIMOTA YB9 SRI 600 1996-1999
BIMOTA SUPERMONO 650 1995-1996
BIMOTA SUPERMONO BIPOSTO 650 1996-1997
BIMOTA DB 2 SR EDIZIONE FINALE 900 1997-1998
BIMOTA MANTRA DB3 900 1995-1998
BIMOTA DB 4 904 1998-1999
BIMOTA DB4 I.E. 904 2000>
BIMOTA SB 8 K 1000 2000-2004
BIMOTA SB 8 K 1000 2005>
BIMOTA SB 8 R 1000 1997-1999
CAGIVA MITO EURO 2 125 2004-2006
CAGIVA MITO EV 125 1994-1999
CAGIVA MITO EV 6 speed 125 1999-2000
CAGIVA N1 PLANET 125 1998-2003
CAGIVA RAPTOR 125 2004
CAGIVA SUPERCITY 125 1997-1999
CAGIVA RIVER 500 1995-1998
CAGIVA RIVER 500 1999
DUCATI MONSTER 400 2005-2008
DUCATI MONSTER 600 1993-1999
DUCATI MONSTER 600 2000-2001
DUCATI SUPERSPORT 600 1994-2001
DUCATI MONSTER 620 2002-2005
DUCATI MONSTER DARK 620 2005
DUCATI SPORT 620 2003
DUCATI MONSTER 695 2007
DUCATI 748 748 1999-2002
DUCATI MONSTER 750 1996-2002
DUCATI SPORT 750 1974-1976
DUCATI SUPERSPORT 750 1999-2002
DUCATI SPORT 800 2003
DUCATI SUPERSPORT 800 2003-2004
DUCATI SUPERSPORT 800 2005-2007
DUCATI 851 BIPOSTO 851 1991-1992
DUCATI SPORT 851 1990
DUCATI 888 888 1993-1995
DUCATI MH EVOLUZIONE 900 2001-2002
DUCATI MONSTER 900 1993-1999
DUCATI MONSTER 900 2000-2002
DUCATI SUPERSPORT 900 1992-1997
DUCATI SUPERSPORT 900 1998-2002
DUCATI 916 BIPOSTO / STRADA / SP / SENNA 916 1994-1998
DUCATI 916 SPS 916 1997
DUCATI 996 996 1999-2001
DUCATI 998 998 2002-2003
DUCATI SPORT CLASSIC PAUL SMART 1000 2006
DUCATI ST3 1000 2005-2007
DUCATI SUPERSPORT 1000 2003-2006
GILERA GFR 125 1993-1994
KTM SUPERDUKE 990 2005
LAVERDA GHOST 650 1996-1997
LAVERDA GHOST 650 1998>
LAVERDA SPORT 650 1995-1997
LAVERDA SPORT 650 1998-2002
LAVERDA STRIKE 750 1998-1999
MOTO GUZZI BREVA 750 2004-2005
MOTO GUZZI NEVADA CLASSIC 750 2002-2005
MOTO GUZZI DAYTONA 1000 1991-1994
MOTO GUZZI DAYTONA RACING 1000 1996>
MOTO GUZZI BREVA 1100 2005-2006
MOTO GUZZI CALIFORNIA EV SPECIAL 1100 1997-1998
MOTO GUZZI CALIFORNIA EV SPECIAL 1100 1999-2000
MOTO GUZZI CALIFORNIA EV TOURING 1100 2003-2005
MOTO GUZZI CALIFORNIA JACKAL 1100 2000>
MOTO GUZZI CALIFORNIA STONE 1100 2002-2005
MOTO GUZZI CALIFORNIA TITANIUM 1100 2003-2005
MOTO GUZZI GRISO 1100 2006
MOTO GUZZI SPORT 1100 1996-1999
MOTO GUZZI V10 CENTAURO / GT 1100 1997-1999
MOTO GUZZI V11 CAFE' SPORT BALLABIO 1100 2003-2005
MOTO GUZZI V11 COPPA ITALIA 1100 2003-2004
MOTO GUZZI V11 COPPA ITALIA 1100 2005
MOTO GUZZI V11 LE MANS SPORT-NAKED 1100 2002-2005
MOTO GUZZI V11 LE MANS-NAKED 1100 2001-2002
MOTO GUZZI V11 SPORT 1100 1999-2000
MOTO GUZZI V11 SPORT 1100 2001
MOTO MORINI 9 1/2 1200 2007
MOTO MORINI CORSARO 1200 2006-2007
YAMAHA DTR 125 1989-1991
YAMAHA TZR 125 1999>
YAMAHA TZR R 125 1992-1998
YAMAHA FZX-ZEAL 250 1993>
YAMAHA TDR 250 1987-1992
YAMAHA TZ GP 250 1996-1997
YAMAHA TZR 250 1989-1992
YAMAHA SRX 400 1991-1995
YAMAHA SRX 400 1996>
YAMAHA SZR 660 1996>
YAMAHA FZR 1000 1989-1991
YAMAHA FZR 1000 1992-1993
YAMAHA FZR GENESIS 1000 1987-1989
YAMAHA XJR 1200 1995>
YAMAHA XJR 1300 1998

 

[Signal]

With the help of information generously supplied by KevC, 650 Central and Vintage brake I have fitted a Brembo floating disc with a10mm Brembo master cylinder, Yamaha R1 calliper, and a braided line.

The work involved making an adaptor plate (KevC even posted drawings!) for the calliper and a spacer for the disc. It was a tight fit so I took a bit off the inside of the lower fork to give a bit more clearance for the disc rivets.

Someone in Europe has even managed to fit dual Brembo discs with R1 callipers.

The disc and master cylinder came from 650 Central. The ratio of the 10mm master with the R1 calliper gives the feel I like. I can't remember exactly what the ratio is but Vintage Brake has an excellent look up table on their webpage.


This set up is lighter than stock and works really well.

 

[jacksdad]

I built up my XS with a standard single disc, but the master cyl was usless so I fitted one off an XS with twin disc conversion, maybe an XJ 650? Its a 17mm bore, and the brake was garbage, just no bite at all unless I squeezed it to death!
Just rebuilt the standard 14mm M/Cyl, put back on with same lines and caliper as before, the brake is now fantastic, totally different than before, more feel and more bite
So I reckon the best size to go for...is the one that Yamaha built it with!