One step forward, Two steps back

Well, I thought I was making progress on the lower battery tray. The concept is a single sheet of cleverly cut and bent aluminum to form a "belly pan" that actually is a tray for holding batteries. I've got an initial 3-d model designed and printed ready to mock up.

The issue comes down to bending radius. The recommended minimum radius for bending 5052 Aluminum is .5 to 1.5 times the material thickness. With my 3/16" sheet, I figure that a .25" radius is about as small as I want to go. In discussing bending capabilities with the premier bending shop in the area they only had small radius tooling on their Brake, admitting that some cracking will occur at the bend.


I'm not to0 wild about cracks in my battery tray, so I will be building a homemade Brake on my workbench. Another project within a project. Obsessive? Anal Retentive? Ridiculous? Sometimes it's a gift, most days a curse.


I bent a 2" strip of 3/16" aluminum (6061-T6) in a vise using vise grips and small aluminum plates with a rough .25" radius, just to get a feel for the force required, and judge the bracket layout better. It took a lot more force than I imagined but turned out pretty good. Even with the .25" radius tooling, there were lots of micro-cracks in the radius, but that shouldn't be a problem with 5052 since it's more pliable.

Controller Crazed

My Alltrax 7245 controller and Magura throttle came in from Cloud Electric. I love blue anodized aluminum. Too bad the contoller will be tucked away under the tank.

I had initially thought of centering the contoller in the fuel tank area, but that would require an addtional cross member to support it. By using the existing cross member, a thick walled piece of rectangular tubing, the contoller is located toward the back of the fuel tank. That will free up the front of the tank for other electrical components and cables.

A little frame modification was required to have access to the inside of the rectangular section. There was already an opening on one side, I just needed to duplicate the opening on the left to allow room for a wrench and to get the bolt placed. The section of the tubing is almost 3/8" thick so I'm not too worried about affecting structural integrity when removing another piece.

Gettin' the Blues

I'm still in the process of designing the lower battery tray. So far, I've gone through dozens of revisions in the solid modeling program, a tedius and frustrating process. Against all the recommendations of my fabrication advisors, I'm leaning toward a single piece of 3/16" Aluminum plate with strategically placed bends. It's a Gixxer - it's got to be aluminum.

Patience is a virtue, but no hands-on activitities on the bike were gettin' me down. I decided to paint the tank. I was going to fix it up right and have it shot with automotive paint, but the tank has had more work done than Joan Rivers. Multiple layers of body filler and primer were evident in several areas, so I decided to go cheap on this revision and save my money for some AirTech pieces.

Rustoleum's finest Blue is fairly close to the color of the motor and just what the doctor ordered. Careful observers will note the lack of stupid looking vent cap and tubing on top of the tank. A friend of my sons recommended I turn the vent assembly into a beverage dispenser! While entertaining, I thought some form of ventilation would be a good idea. A small mag-lev fan will do the trick, I hope.

Action Flick

I just had to do a quick connect with 12V to see the rear wheel turn under battery power. Most triumphant!

The battery's I used are some burned out SLA's from a UPS. I've been placing them on a charger to see if they can be recovered, but they wont hold a charge over 13.2V. Good enough for the demo and testing phase though.

Holy Oversized Sprockets Batman!

In order to maximize acceleration, I needed the biggest rear sprocket that would fit. I measured the clearance avialable on the swingarm and a 71 tooth sprocket would just barely fit. So to give myself a little extra room, I decided to go with a 68 tooth unit. Combined with a 12 tooth in front, the gear ratio of 5.66 is a little high, and will sacrifice top speed, but I'm not too interested in going on the freeway. If I decide freeway speed is needed later, I can always put in a 14 or 15 tooth front sprocket.

The front sprocket and chain arrived from Grainger a few days ago, but the rear sprocket from Sprocket Specialist was taking it's sweet time. After finally arriving, I nearly choked at how big the sprocket was. Had I made an error calcualting the sprocket size? I estimated the 68 tooth sprocket at 13.75" diameter, but it looked like 16" to me. You know that saying "measure twice, cut once"? Well I'm famous for cutting twice, and sometimes more.

A tape measure told the truth: 13.875" (whew!). Still looks pretty big to me.

After putting together the hub and sprocket, I threw the rear wheel in place and cut the chain to length. Sprocket has a least 1/4" clearance from the swingarm, the chain fits and lines up just fine. Even the mislocated bolt pattern for the motor is not going to be a problem.

At this point, I'm feeling a little lucky and may go buy a few lottery tickets.

Motor Mount v2.0

Ok, so it's not completely bolted up yet, and there are still a few hiccups to iron out on the final design, but the motor mounts are on!
You might notice the extra hole near one of the bolts for the motor face. Oops, the dummy running the mill forgot to zero the x & y axis before moving to the position for the first hole. To cover my mistake, I ended up rotating the bolt pattern 14 degrees, so now the chain will have less clearance for the mounting bolt closest to the swing-arm.

I'm also not thrilled about the flanges I bolted on to provide a clamping action around the motor, as they look a little cheezy. I would have been better served by a couple of pieces of 3/4" x 1" aluminum stock.

Another lesson learned: plasma tends to cut features about .075" smaller that drawn, so I ended up doing a lot of handwork to enlarge the internal diameters on both brackets.

Plasmarrific Motor Mounts

So it turns out that the tapered plasma cutting path was indicative of a worn electrode and nozzle. With a fresh electrode and nozzle, I gave the plasma cutter another shot.



Another lesson learned from the first go-around with plasma is to orientate the pattern so the more accurate side is facing up. In my case, the left bracket was cut with the side that faces the motor on top.