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Center Stand Tabs PDF Print E-mail
Written by BMWVMCA NEWS   
Sunday, 08 April 2012

from Richard Sheckler

  Gentlemen,

       Here's the dope on the center stand brackets. Donald is asking $35.00 per set of two. If you have one or more plunger frame bikes with damaged or worn out center stand tabs, these are what you'll need to make repairs.  Expect to add $9.00 for postage for up to 5 sets, and about $13.00 for up to 15 sets.

       Donald sprang for this project out of his own pocket. He had 45 pairs available at this writing. Let's support his efforts.       Donald's contact information is shown below.      ED

        Technical data for your reference: The original shape is carefully maintained, but outer profile is slightly enlarged by about .030" (.8mm) for improved strength. Critical pin hole to cross tube distance is as original. The material is 4130A annealed chrome/moly steel which is about 35% stronger and harder than mild steel. Fatigue resistance is excellent. The material is what aircraft frames, bicycles and race car suspension components are made from. Thickness is .190" (4.8mm). 12mm pin hole is reamed to exact size.    

        I can also supply them un-reamed (11.5mm hole) if desired. I think these will fully correct the center stand bracket problem and will yield a perfect lifetime repair.

        Because the tabs are 4130, care should be taken when welding. Oxyacetylene fuel or TIG processes are both okay...ER70S2 filler rod is the one to use. Good fit-up is important, so dressing the cross tube for a gap-free fit will lower the ultimate heat input required to weld them. A little preheating of the joint is helpful in a cold shop (100-150F is fine). This can be done with a heat gun or propane torch. Allow the welds to cool slowly in still air (no breezes or fans). Under no circumstances should the welds be quenched, as this will embrittle them.

        Because the 4130 is so tough, I would take care to carefully align the tabs with a dummy pin, bolt, or threaded rod and spacer or nuts. Leave the fixture in place till fully cooled for tacking and the first (outside) welds. Once the tabs are heated from welding, they will be quite hard and difficult to re-drill or ream to correct any alignment problems.

Donald Cope

130C Ware St.

Athens GA 30601

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Last Updated ( Friday, 25 January 2013 )
 
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