Single 320MM rotor and fancy brake on the 950?

Discussion in 'Dakar champion (950/990)' started by Ricardo Kuhn, Nov 27, 2004.

  1. AntWare

    AntWare Lost In Translation

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    If the 950 came stock with a single front caliper, there'd be a huge aftermarket for a twin disk conversion kit :lol3

    For those that have gone single up front, how does the single disk feel with a loaded down bike or a passenger onboard?
    #41
  2. Stephen

    Stephen Long timer Supporter

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    :poser :poser

    Stop it, yer killin' me.
    #42
  3. Flanny

    Flanny Flanny-it-up!

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    The single 300mm is great off-road, but inadequate on the street, and in particular when the bike is loaded. That is why I'm looking to even out the overall compromise with a 320mm disk.

    I also think that getting the 4 piston caliper would alse very likely bring to bike back to similar braking power as with the twin disks, so I'm opting to go with the two piston caliper and 320mm disk as the "middle-ground" compromise.

    IMHO the single disk mod is really only a good idea if you ride enough off-road to get annoyed with the front end locking into turns and stuff. If you don't have a problem with the grabbiness to begin with, then you'll definitely not be impressed with the remaining braking ability on the road. :thumb
    #43
  4. AntWare

    AntWare Lost In Translation

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    Cheers Flanny, be interesting to see how things work out.

    Another 950 rider (who was thinking of making the single disk switch) and I rode to Big Bend a few months back. I think riding the loaded down bike on the highway gave him food for thought. Tucking the front at 50 on the dirt is one thing, having a deer run out in front of you at 120 is another :lol3
    #44
  5. Greg Minor

    Greg Minor The Trespasser

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    I could have used my other disk the day of my crash :vardy
    #45
  6. Stephen

    Stephen Long timer Supporter

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    Y'know, this thread has me thinking (uh oh) about the pads. Galfer Greens chaned the KLR front brake utterly, stronger at full pull, yet far less grabby. Perhaps there's a middle route besides Flanny's; I find the initial grabbiness disconcerting in the dirt, too, and maybe some Galfer Greens would help.

    I should mention that the stock setup is not nearly so grabby once it gets warmed up, but I've noticed that it takes some good squeezes to make heat.

    Hmm, and maybe the Galfer Black will cure the squealing in back...

    I like the Galfer pads, as they work well. They do wear pretty quick, don't know if quicker than KTM stock.
    #46
  7. Gummee!

    Gummee! That's MR. Toothless

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    [hijack]Hey Greg! Howya healin? I'm in escrow (selling the condo) and am gonna have $$ for a DS bike here in about 26 days. Any ETA on yer "get back to ridin day?"

    M
    [/hijack]
    #47
  8. KTMax

    KTMax Ninth of the Nazgul

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    This is a jawdropping thread if there ever was one.... :lurk
    #48
  9. motozilla

    motozilla Long timer

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    NO THEY WILL NOT!!!!!

    I have a set right here and first of all, the calliper is the same. Secondly the calliper hanger is different and won't work.
    #49
  10. Rbott

    Rbott Been here awhile

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    Motozilla,
    What about using a 450 EXC caliper with a 320mm rotor and relocation bracket? I was thinking a Braking 4 piston supermoto caliper and a Braking Wave rotor. I will see if it will work when I get my 950 wheels back, unless you already know the answer.

    Ryan
    #50
  11. motozilla

    motozilla Long timer

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    That *might* work....I have a 320 mm rotor here and I went to mount it on the 950 but it was a no go. The hanger is the problem (wrong bolt spacing) but the spacing might be correct for the 450. I can tell you the the Braking 4 piston unit is too wide for the 950 wheel (It hits the spokes) but it looks as though the motomaster works.
    #51
  12. BigMac

    BigMac Been here awhile

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    The stock twin disc front setup doesn't accomplish a whole lot on road or in dirt. It however has little-nothing to do with braking power, imo, it has to do with feel. The stock setup simply lacks feel and ability to modulate either on road or dirt. What the exact cause for this is could be several factors including pads, rotor, caliper, line crossover routing, fluid or master cylinder...or a combination of several.

    My solution for last 8k miles has been to jetison the right front rotor, caliper and crossover line, install Galfer Green pads on left caliper, install a Brembo GP 16mm radial mc and Motul 600 fluid. The feel is dramatically improved, literally night and day difference. Having spent many of these miles in dirt, mud, wet rocks, gravel and the occasional wet roads, I am sufficiently satisfied with this setup that I am not presently considering a 320mm full-floater setup with 4 pot Brembo Goldline I had previously being considering. I have not however been involved in any situations that have required emergency stopping power...thankfully not yet! If I had to guess, I'd think the new master cylinder and fluid were the primary contributors to the improved feel and modulation although I do think the Galfer pads improve stopping power over the KTM OEM units. Take care.
    #52
  13. Greg Minor

    Greg Minor The Trespasser

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    Mike I'm several months away I'm just starting my physical therapy today I walked for a little while without my crutch. After I'm healed up I then have to convince my wife to let me ride again As of now, its you ride I leave (mind you with half) She's afraid I end up like Chistopher Reeves I hoping time will help Good news on the bike :)
    #53
  14. sakurama

    sakurama on an endless build

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    Hey flanny, I'm working on trying to reverse engineer the setup on Ricardo's friends bike. Can you tell me the center to center distance of the 640's fork's brake mount tabs. The 950 is 96mm so I'm trying to figure out what KTM Ricardo's kit was supposed to fit. It's not the 525 I now know so I'm guessing it must be a 640 setup.

    Gregor
    #54
  15. Flanny

    Flanny Flanny-it-up!

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    I'll measure tonight and post for you later.
    #55
  16. sakurama

    sakurama on an endless build

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    Well I can tell you that you really need to be committed if you want to do that Motomaster swap. I just finished it and it wasn't easy. The main problem you will run into is the spacing between the spokes and the caliper. This is the reason that 2-piston calipers are used. To move the caliper out requires moving the disk out. Moving the disk out requires machining either the caliper bracket or the forks caliper bosses in order to keep the spacing.

    I wanted to do this project with the stock Motomaster kit and caliper bracket with the minimal work so it could be duplicated. At worst I was hoping that we could make a small run of caliper brackets that would solve the problems and sell them here to those really wanting to go this route. In the end it's a bit more complicated. Spacing is so tight that in order to get things to fit, and to leave enough meat on the bracket, I had to machine 3.83mm off the caliper mounting bosses on the forks. I don't have everything solved as for some strange reason my speedo is now reading 170% high - or maybe it's double which might make more sense.

    The good news is that the single Motomaster caliper and 320mm rotor end up being about the same power as the stock double disk setup which is what I was hoping for. I left the stock master cylinder for now since I figured it was calibrated for four pistons (spread over two calipers) and I'll let the brakes bed in with this setup and then I'll swap out to the 16mm Brembo radial master cylinder to see how that effects things. I suspect it will improve the feel greatly since it's done that on all the other bikes I've put them on.

    I'll post some photos on Monday but I think the conversion seems to be a success so far.

    Gregor
    #56
  17. 950TRANSALP

    950TRANSALP Been here awhile

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    Any one try Galfer wave rotors , ADVMOTO.com , front and rear they have slotted vents and should keep the rear from locking as easy. Front should be more progressive , etc... lighter etc...cooler etc... Let us know ! K.B.
    #57
  18. MooreRon

    MooreRon Banned

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    Didn't read through 4 pages of replies, so forgive me if this has already been said, but if you ride the 950 off-road, a floating rotor is a bad idea. Dirt, mud, sand, etc., will get wedged in the area that makes the rotor 'float' and it will not float anymore. You will then have a rotor that is not true.
    #58
  19. XtreemLEE

    XtreemLEE insignificant being...

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    Why not have the best of both worlds?

    Beringer who makes the supermoto conversions for the RFS motored line of KTM's also makes...

    A twin disc setup that is two discs on one side with a caliper that has three brake pads in it. One on each side and a double sided in the middle.

    http://www.beringerbrakes.com/4d.html

    Trying to stop that big bike with a single disc I think you are going to have heat problems. I would try a one sided 4d system (2d) before letting a sngle disc do the job.

    My new EXC450 has the beringer super moto 4 pot brake on it and it stops the damn thing, but the weight is quite a bit less.
    #59
  20. MvZee

    MvZee Been here awhile

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    ... for me to respond to this thread seeing as I am the friend of Ricky's to whom this bike belongs!

    First off, I want to publicly thank Ricky for his help in getting the bike ready for it's "extended Beta" ride to test the new brake system. THANKS RICKY!!!!

    First let me say, the only machining that was necessary, involved a hack saw and file to remove the ear on the left fork leg that holds the old fender in place. It was in the way for the new placement of the metal wire brace for the brake line, so after a couple minutes of debating whether we would regret the decision later, it was exercised with extreme prejudice!

    Now on to some details. Rotor and caliper spacing is critical for the caliper to not hit the spokes. We ended up spacing the rotor out a little over .100" and then shimming the caliper to recenter it on the rotor (as near as possible) and provide clearance for the spokes. We used bearing shims behind the rotor, available at a local bearing house. With the rotor spaced out, there was clearance problems with the stock bolts that hold the rotor to the hub. High grade button head screws were used to provide the necessary clearance for the bolt heads. As the bolts appear to do double duty to hold the rotor on and provide a sensor (or in this case 6 sensors) for the speedo pickup, they run sufficiently close enough to the stock pickup, that the speedo works flawlessly without any changes necessary. I'm still not entirely satisfied with this solution, and Ricky and I have recently discussed rebuilding the front wheel with a single rotor hub with the needed offset built-in and the wheel dished to recenter it. Since the rim was bent on the fore-mentioned "extended Beta", it needs to be replaced anyway.

    Shortly after the conversion, the new system was put to test. Here are some pictures of the vehicle during this test phase:

    Here is the test vehicle on its "Extended Beta" with newly installed brake at the "Earthquake Capitol of the World" -- Parkfield, California
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    Somewhere south of Parkfield
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    On the Carrizo Plain between Highway 5 and 101 (http://www.carrizoplain.com/)
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    Morning rush hour traffic on the Carrizo Plain
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    In Northern Baja approaching Parque Nacional Constitucion:
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    Still in Northern Baja coming out of the mountains
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    Brake dust can be a problem with the big 320mm rotor and 4 piston caliper. This is easily rectified as shown. This is on the mainland coming over a set of mountain ranges from Talpa de Allende (about 50 miles east of P.V.) en route to P.V.
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    The test vehicle on the edge of the road approaching Real de Catorce
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    Overlooking the valley in the hills around Real de Catorce
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    There were some straights where you could achieve a little speed to test the straight line stopping ability of the brakes
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    And there were some curves that permitted use of the brakes as well
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    Some twisty dirt roads were thrown into the test program
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    A little cold weather testing was performed
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    Yet more unpaved road testing
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    A small break during testing was allowed to greet fellow AdvRiders
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    Returning via Highway 1 on California's coast I was met with a procession of sightseers and motorhomes as far as the eye could see. Wait... that's not it at all. This is what the traffic on Highway 1 was like between late winter storms
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    All told, 8000 miles were racked up in 2 1/2 months of testing the brake system in a variety of conditions. The brakes held up without a problem, and there were no problems with the floating rotors losing their ability to "float" regardless of the conditions that were thrown at them! Further testing and development continues.... Stay tuned!
    #60