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  1. #1
    Join Date
    Oct 2009
    Location
    Rocklin, CA
    Posts
    5

    Default Intro

    I wanted to introduce myself for those who don't me. My name is Mike Guidera and I own EMS. I started the business 10 years ago with one product, the 2V shim kit and now have many products that I offer including shims and kits for all Ducatis and many helpful tools to assist in the valve adjustment
    process.

    I have quit a bit of experience with Desmoquattro motors, though I have never owned an 851 or 888. All my experience with these types of bikes have been with two different 916's and an ST4 which is my daily ride.

    If you have any questions concerning valve adjustment or any products dealing with valve adjustment (MBP Retainers, etc.) feel free to post up and I will try and answer them.

    thanks
    Mike

    www.emsduc.com

  2. #2
    Join Date
    Sep 2009
    Location
    westbury
    Posts
    977

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    Welcome Mike
    Are the mbp type collets avaliable again?
    Regards Steve

  3. #3
    Join Date
    Oct 2009
    Location
    Rocklin, CA
    Posts
    5

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    Hi Steve,
    The 7 mm MBP Collets are being machined as I speak. Once machined, they get heat treat, tumbled, and EDM wire cut. Hope to have them on the shelf in about 4 weeks.

    Mike

  4. #4
    Join Date
    Aug 2007
    Location
    FRANCE
    Posts
    865

    Default

    Welcome Mike,

    I'm quite convinced that some of us would appreciate further infos regarding MBP collets, compared to OEM half rings ...

    Thanks

    Phil911

  5. #5
    Join Date
    Oct 2009
    Location
    Rocklin, CA
    Posts
    5

    Default

    A little history first on the MBP retainers.

    The stock half rings in the desmoquattro bikes are somewhat on the edge of an adequate design. If the closer clearances get too large, or if the bike is run at sustained high revs especially with radical cams, the half rings can break during use. Usually, catastrophe is avoided as the half rings are contained under the opening shim and even the broken pieces will still hold the closer shim onto the valve stem. Another problem with the stock half rings is that they are rather soft and do deform over time, thus increasing the closer shim clearances.

    Back in the late 90's, Guy Martin of MBP came up with the idea of machining the the retainers out of tool steel and then harden them. The result was a superior design that resists breaking and deforming during use. During a race at Daytona in the 90's, a 748 race bike kept breaking the stock half rings with the result of blown motors. The MBP collets were then installed and the bike went on to podium finish.

    Here are the differences between the stock half rings and the MBP retainers:

    Stock Half Rings- made from spring steel. Made on a wire forming machine, formed around a mandrel. Surface Hardness around Rc 45. Ends cut mechanically, and not necessarily square. Deforms with use, can break under extreme conditions. Round in cross-section. Not very stiff.

    MBP Retainers- made from tools steel, precision machined. Cut in half after machining with a wire EDM machine (very precise, ends square). Surface Hardness around Rc 63. Does not deform during use. Is also stiffer than stock half rings due to larger bending moment of inertia (geometry is different with more material. Withstands extreme conditions (race, track use). Approximately doubles the valve adjustment intervals.

    If MBP retainers are used in 4v motors, then modified opener shims must be used, because the MBP retainer protrudes up past the groove in the valve stem and will interfere with the bottom of a stock opener shim. The modified opener shims has a counterbore in the bottom to make room for the MBP retainer.

    The MBP retainer is a superior mouse trap. You will see the advantages of the design the harder you run the motor. The stock half rings are adequate, but if you want a better retaining system the MBP retainers are a good choice. I have put many miles on ducatis with and without the MBP retainers. I have 55,000 miles on my ST4 with stock half rings. I now adjust the valves every 10,000 miles, but have changed out shims every time I do the adjustment. I had a 916 track bike and put on 3500 track only miles. I am and ex road racer, so could run the bike very hard, hitting the rev limiter routinely. After 5 years of track days, I checked the valves and only one closer clearance changed by .001 inches. All other clearances remained the same.

    In the past the fit of the retainers have been somewhat of an issue. This is because they are made from tool steel, are stiffer and do not deform easily during installation. The stock half rings are fairly soft and much less stiff. They also have fitment issues but deform easily to snap into place if needed to.

    One problem we were having was that during heat treat the MBP retainers would deform slightly thus causing them to fit tight. But they all would not deform the same amount, which made it really tricky to get them all to fit the same. I came up with an elaborate inspection method to determine the extent of deformation and using electropolish would then remove a very small, precise amount of material to get them to fit properly. I came up with a change in the design of the retainer that should alleviate this problem. Turns out the 8 mm MBP design, do not deform during heat treat. So we came up with a design similar to the 8 mm for the 7 mm retainers. We found the problem to be gross change in cross section of the old 7 mm design. The new design minimizes cross sectional change, but still keeps the same contact area with the closer shim.

    I hope this explanation has shed some light on what MBP retainers are all about.

    Mike

  6. #6
    Join Date
    Aug 2007
    Location
    Cornwall S.W. England
    Posts
    5,019

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    Hi Mike and welcome to the forum,

    I bought some spare MBP retainers from you around Christmas time and posted on here that they were still available from you.
    I've a huge collection of shims that I've kept topped up over the years by buying shims from you.
    I've spent quite a bit of time on the lathe (a couple of days at least) converting them to fit with the MBP retainers, by counter boring them wearing out at least 3 specially made tools...
    Not cheap even when doing the actual work myself.

    Some time back I saw on the MBP website a different way to modify them, the drawing showed them just being shortened by 1mm instead of counter boring them by 1mm.
    What's the craic here then? Is it OK to just face them off by 1mm?

    Steve R

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