Twin-cylinder four-stroke air-cooled rebirth of a Ducati 500SL



This is a partial list of hardware that I replaced on my Marzocchi M1R forks. Eventually, I will organize this to include both low-cost and fancier metal and coating options. Izaac (from Pantaheads) just turned me on to yellow zinc screws. Now I have to start my list over.


  1. Eagle Day
  2. McMaster Carr
  3. Fastenal


Rebound adjuster:

  1. #8-15 x 5/8″ Phillips Flat Head Sheet Metal Screw [A4 316 SS]  x 1
  2. Black-Finish Steel Internal Retaining Ring for 17mm Bore Diameter x 1
  3. Metric Spring Steel Shim – DIN 988 0.1mm Thick, 10mm ID, 16mm OD x 1
  4. Metric Buna-N O-Ring 1.5 mm Width, 11 mm ID x 1
  5. Metric Buna-N O-Ring 1.5 mm Width, 5.5 mm ID x 1
  6. M6-1.0 x 20mm Socket Head Cap Screw [A4 316 SS] x 2



Bottom of forks:


Cross brace:



When you remove the connecting rods, be sure to mark the top and bottom halves with permanent marker. This way, when you reassemble them you can guarantee that they will be correctly balanced. Don’t forget to mark which one is attached to the vertical cylinder and which one is attached to the horizontal cylinder. On the Ziploc bag, draw the arrangement of the connecting rods in relation to a marking on the crankshaft as well. When you go to put them back in a few days-weeks-months-years it will help ease the fear that you are not reassembling them correctly.


Markings on top of standard pistons pulled from a 1986(?) Ducati (Cagiva) 650 Alazzurra engine have the following markings:

  • 82-67677A => (arrow) on the top
  • “A” logo on the inside
  • Made of aluminum
  • 3 rings (2 sharp metal, 1 with a spring in it)