I see a lot of threads about handguards and top clamps which often touch on the products from Highway Dirt Bikes (HDB), but no dedicated thread, so here we go.
In September, 2009, after looking around at all the options available, I decided on the HDB top clamp and handguards for my 2008 WR250R dual sport. Needing a place to mount two powerlet outlets, and not wanting to add extraneous brackets, I started looking into integrating the powerlets into a handlebar top clamp. The original version of the HDB top clamp has 4 small switch holes in the upper portion. I was curious if these could be drilled out to accommodate the 18mm hole needed to mount a powerlet so I contacted Paul, at Highway Dirt Bikes, to get the ball rolling.
Here is a pic of the original top clamp that got me thinking:
After a bit of discussion on clearances and research on the various powerlets available, Paul worked up the following, replacing the four small switch holes with two 18mm holes.
I decided to go for it, so completed an order to include the top clamp, lower clamps with some rise, hand guards, Protaper Evo bars (which he tapped for me), and some of the flip out mirrors.
Then I received an email from Paul with a new idea he had worked up and, suddenly, all was right with the world.
In this image of the new design, you can see he left the top portion of the top clamp as it was in the original design but added material to create a lower portion in which the two 18mm powerlet holes could be drilled:
Paul ordered the needed material to do a run of clamps. Since I was moving to fat bars, I needed a 100mm x 40mm bolt pattern. Stock bars, or any 7/8 bars, would have used a 100mm x 33mm bolt pattern on this bike.
After a couple weeks, the first run was complete and I was pleased to receive this image of the new top clamp design with a low-profile powerlet mounted.