The EAGLE Lever is sold by ARROWHEAD MOTORSPORTS
A while back, a friend and customer, Elden Carl, asked me to come up with a new balancer adjustment plate for the KLR650. I looked at the 2 samples of Kawasaki parts he provided, and measured them. I have now measured 5 eccentric shafts that the plate retains in position, the 2 styles of bolt, and the case the plate is bolted to.
The factory eccentric shafts varied in thickness and diameter where the plate attaches by about .002 inches, total. The case (generator case cover) is not flat where the plate is bolted down.
The factory plates are very soft - in one instance, I observed the slot had been crimped enough around the bolt that even if a rider tried to adjust the counter-balancer eccentric, it would not move under the power of the spring.
Also, the shaft hits in the corners of the "double D hole", so that when wear occurs, the shaft will be allowed to rotate a fair amount. (Again, the soft part will wear quickly.)
When I designed this part, I had to allow for the irregularity of the case surface, and the variance of the Kawasaki eccentric shafts. I considered a set screw to retain it on the shaft during the adjustment process, but if you look at how this part fits, and works, this isn't really a good idea. This could also prevent the part from seating down on the case surface. I decided to "clearance" the corners of the "double D hole", to maximize the actual load bearing surface.
I chose a heat treatable stainless alloy, that I know has great strength, and corrosion resistance as a side benefit. It also has very good toughness - not brittle. This alloy has been used in many aerospace applications, including passenger carrying aircraft, as well as cruise missiles. The material that I chose is more than twice as strong as the factory part, besides the great increase in strength from making it a solid, 1-piece part.
The design also increases the bearing surface (along the shaft) by about 100 percent in length. I also re-indexed the part to allow adjustment for the entire useful life of the chain.
My lever is made from 17-4PH stainless steel, heat treated to 44c on the Rockwell scale. People have asked me why not make it from 4130 carbon steel. 4130 will not get as hard as this. 4130 can be CASEHARDENED to get a hard layer, but it WILL NOT be as strong as the 17-4. I have confirmed this with the quality control manager at Certified Metal Craft, in El Cajon, California (San Diego area). I chose 17-4 because it was the best material for the job - not because it was stainless steel.
Certified Metal Craft is an aerospace approved heat treating company.
Elden Carl (a very demanding customer), Tim Bernard, Kurt Simpson, Conall O'Brian, and others all have chosen the Eagle Lever.
Ride safe and happy!