Saturday, January 23, 2010

- Highway Dirtbike (HDB) Powerlet Top Clamp

In late 2009, I started looking for a handguard solution for my WR250R dual purpose. Wanting hand guards that attached to a top clamp rather than running back to the bars left me two options; Fastway F.I.T System and Highway Dirbike (HDB) system.

I wanted a place to mount two powerlet outlets, and not wanting to add extraneous brackets, I began investigating integrating the powerlet outlets into the handlebar top clamp. The original version of the HDB top clamp (seen below) had 4 small switch holes in the upper portion. I was curious if the billet aluminum could be drilled out to accommodate the 18mm holes needed to mount powerlets so I contacted Paul, at Highway Dirt Bikes, in September, 2009 to get the ball rolling.

The original top HDB top clamp:

After a bit of discussion on clearances and research on the various powerlet outlets available, Paul worked up the following, replacing the four small switch holes with two 18mm holes.

The design looked great to me. I placed my order for the new top clamp, lower clamps more rise that stock, hand guards, Protaper Evo bars (which he tapped for me), and some of the HDB 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 the below 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.

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 outlet mounted.

Shortly thereafter, my setup arrived. Looks good even on the kitchen floor.

Top clamp being installed. Note the hand guards are not yet installed in this picture, but the two handguard brackets are affixed to the top clamp.This image shows my view from the seated position so the instrument cluster is not blocked by the taller bar setup.

The below image shows the HDB custom lower clamps. These risers are about 2" taller than stock. I chose a bar bend that was 1/2" shorter than stock netting me 1.5" of rise over the stock height. It really has opened up the cockpit. I will have plenty of room to use the standard powerlets, if I want, rather than the lower profile powerlets. I wanted to get my rise from the bar clamps rather than from handlebar bend so this worked out great.

The mostly finished handguard install. Here is a shot before putting on the mirrors and shields.

As mentioned earlier, I used custom HDB lower clamps with about 2" of rise over my stock clamps. The bar bend is 1/2" lower than stock netting me 1.5" of rise over stock.

The shields and mirrors are installed. In this image, I've changed the handguard orientation compared to the first two photos. They are angled lower here to improve the view from the mirrors yet still give me the needed protection from wind and branches. I'll adjust them to their final position once I get a few rides in. Note the clutch is out of final position in this image, as are some of the other controls. I was still tweaking positioning of everything.

[Update:  I've been using and abusing the Highway Dirtbike handguard and top clamp system for two riding seasons and am quite happy. Having the powerlet outlets in the top clamp is handy and the handguards themselves are much stronger than any other handguards I've used in the past. They hold there shape in crashes unlike thinner bars that need to be bent back into shape with every impact.


  1. LOL I have the same setup, but I copied Bash3r ;) (looks like he copied you).

    Did you get the anti-vibe inserts? My HDB setup has a uncomfortable buzz at high-rpm which is mostly seen on the highway.

  2. Yes, Bill jumped on board as soon as Paul and I designed the powerlet top clamp. He had Paul enlarge the one 18mm powerlet hole to accommodate the High/Off/Low switch for his heated grips. A good setup.

    No anti-vibe inserts for my bars. I'm running the Pro-taper Evo bars and have little to no vibes even though I'm geared down to 13/48 sprockets. Bars are comfortable cruising at 70mph. But maybe that is simply the contrast to my wife's WRR which has 13/52 gearing and becomes a paint shaker at 60-65mph. Ha.