I was originally thinking of using black (natural gas) pipe and drilling the end for putting a "T" bar in, but God steered me past the water shutoff keys in Home Depot, so I ended up with something much better.
The total layout was $8.96 + tax and the tools I already had on hand. Total time, including figuring everything out, was about 2 hours. You should be able to get his done in less than an hour following these instructions.
One of the best things about this tool for me (even beyond the low cost) is that you can remove the damper without putting the fork in a vise.
Required:
- Curb key (I used an Orbit 1/2" x 28" from Home Depot; skew 046878532465)
- 7/16" drill bit (+ drill)
- Something to grind/cut metal (I used both a bench grinder and my Dremel with cut-off wheel)
- Ruler
Before you get going, some things to keep in mind:
- The manual calls for leaving the spring guide in place when removing the piston. This is not possible with this tool, but removing the guide is very easy
- Using cutting oil on the drill will make a mess on the inside of the rod. I decided it would be better to just go slow without oil than try and flush out the mess later
- Not making sure you have rounded off everything can result in a gouged inner fork pipe
- If you don't have the tools and grace to do this on your own, the Honda tools probably work just fine
Ok, let's get going.
The Key

First, drill out the center of the main rod from the bottom. I held the rod with vise grips, propped the key on a jack-stand under my drill press, and went to work. If you are doing this with a hand drill you should probably work your way up to the 7/16" bit. I just went for it, but as already mentioned, I went slow.
Bottom of Key before drilling

Bottom of Key after drilling

Next round the side of the Key so that it easily fits inside the fork pipe. I did this on a bench grinder.

Now using a grinder or in my case, a Dremel cut-off wheel, cut the end of the Key. The end needs to be 8mm wide x 8mm deep x 3mm thick. Because I was flying blind on this, I wend 10mm deep (not a problem). Also, you can and should start at about 4mm thick and then go down to 3 if needed (mine actually tapers from 4 to 3).
When dealing with the thickness, take the material from the outside of the key, not the inside.
Cut Key from the side

Cut Key from the bottom

After you are done cutting, remove any burs, making sure that no sharp edges exist. Also make sure the inside of the key is not jagged so as not to gouge the damper.
Once you are done your key should fit snug on the damper, but not require force to engage.
Key on damper after removed from shock

As you can see from this photo, the key is long enough to remove the damper without removing the seals (fork is extended beyond where the seal would rest)

This is the finished Key

This is the Key with the fork pipe on it. I just stand on the Key when removing, and rest the T of the key against the bench leg when torquing during final assembly

I hope this helps someone else. If a vendor like Motion Pro made a tool for the CRF150R/RB I was not able to find it. If I could have found one I may have gone that route (others are like $25). If you buy the Honda tools (2 tools + the T handle or a screw driver) your going to be in it at least $70.