Tools and Miscellany for the BPF

Pictures and miscellany for later use.
I did have a problem with the MotionPro Seal Driver being too short to seat a bushing in the upper leg of the HD XR1200's 43 mm BPF.  Pictures are below.

MotionPro Fork Seal Driver

This is the MotionPro Fork Seal Driver that I bought.  It will set the oil seal to the right depth - however, the driver is too short to seat the bushing in the upper leg.

MotionPro Seal Driver

The driver will seat the oil seal to a depth of about 0.915".


The end of the driver is recessed nicely to safely drive the bushing.  But the depth of the recess, added to the short length of the driver, means the bushing will never get pushed into its seat.


PVC extension

I had a scrap piece of PVC pipe laying around, which was almost the right diameter, so I split it and shaped it to the slider diameter.  With this .85" of extra length, I could push the bushing into place. 
As it is, if I was doing this often, I would make this piece longer to make it easier to remove after pushing it into the upper leg.
Also, the recessed tip of the seal driver is a nice idea for protecting the bushing, but there is an internal shoulder in the upper leg, so the seal will never get fully seated in the upper tube, if it is protected in this recess.  The PVC piece pushed the bushing into place to the right depth, since it stopped at the internal shoulder of upper leg.



The following pictures are just some other miscellany from my fork disassembly. 
Initially the reason I took the legs apart was to install a piston upgrade.  But when I was doing that, I found that I had slightly bent a lower slider in a drag strip accident a while earlier.  I replaced the bent lower slider last week, but am curious as to whether I can replace (or have straightened) the slider tube to keep a spare leg on hand.



Lower Fork Leg Disassembly

Since I had slightly bent a lower fork leg in a drag strip accident, after replacing it with a new lower slider leg, I decided to disassemble the lower leg to look at the preload adjuster and see whether it is possible to have the lower tube straightened or if I can buy a replacement tube.


After removing the 1.5 mm Allen head set screw from the back side of the fork end...


Heat is used to break the thread locker loose so that the tube can be unscrewed.  I used a propane torch on the tube and fork end, testing every so often to just heat enough to soften the thread locker.  This took a while but did not damage the tube or end.  There are plastic parts in the fork end, so too much heat is not a good thing. 
An old axle can be used to hold the lower bracket and a hard steel rod or long screwdriver inserted in the holes in the end of the fork tube to unscrew it.  The tube will be hot, so gloves and care should be used.
Without heat the tube will not come undone, or the threads in the end of the fork will be damaged.


Here is the 23 9/16" (60 cm) long, 43 mm fork tube separated and ready for repair or replacement.  I'm going to check to see what a frame shop says about straightening the tube, but really I will be looking for sources to replace the tube.


The Preload Adjuster

The plastic cup at the bottom of the fork end is effectively a "screw jack".  It is shaped to the spacer at the bottom of the fork spring, and it is raised and lowered by the adjusting wheel on the side of the fork bottom.
Note:  There are 16 full turns of preload adjustmant in the XR1200's Showa BPF.  That equals 0.170" or about 4.3 mm.  That means that lock-to-lock, there is less than 1/2 cm of preload adjustment.




Removal of the lower slider tube from the fork end is not commonly done.  I only disassembled this far because I had slightly bent the slider tube in an accident and am curious about trying to have it straightened, or find a replacement tube.

To Return to the overview page on the Andreani Piston upgrade, click here.
To Take a look at Installation of the Andreani-Ohlins upgrade, click here.
Specialized Tools, click here.
To return to the XR1200 Tech Info page, click here.

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