Yamaha KYB Fork Cap Tools


I needed to replace the fork seals on my 07 YZ250F and didn’t have the special wrench for undoing the fork caps so I designed this tool to be 3D printed.  It took a few iterations to get the design strong enough but I was successfully able to loosen both fork caps with the final version.

The model was created in Onshape …


Then printed in ABS with 0.1mm layers (should also be fine with 0.2mm layers), 50% grid infill and 1,2mm wall thickness, it took a little over 2 hours to print …


You can see that the bottom layer had a bit too much squish and caused the ‘elephant’s foot’ effect.  I found that the bed was not 100% flat and the leveling method I was using caused the nozzle to be too close to the middle of the bed.

Here it is in action,


To undo the base valve, another tool was required.  This has a an octagonal head for the valve with a regular large hexagon that takes a 27mm socket.

Fork Cap Tool 2
Fork Capt Tool 2 Printed


This time it was printed in ABS with 0.25mm layers, 50% cubic infill and 1.2mm wall thickness.  It took a couple of iterations to get the head the right size to fit snugly into the base valve.  With these two tools I was able to undo the base valve on both fork legs, when they are installed back in the triple clamps, I’ll see if this tool can apply the 21ft lbs tightening torque specified in the manual.

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3D Printing

What is 3D printing?  Basically this involves building a 3D shape by building up layers of material.  The material is most often a plastic (PLA, ABS) filament that is extruded through a heated nozzle but all sorts of materials can be used including filament fused with wood or aluminum. When […]
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