Construction Pg 1

But before I did that I had a decision to make, tubing bender, build it myself or purchase one from someone. I did some research on building a tubing bender and found a couple of solutions. Most included making the dies out of hard wood (oak) and sandwiching it between two pieces of metal. The problem with this methods was that most sites and articles that I read on these indicated that any tubing over ½” diameter just about had to be filled with sand to keep it from deforming. This was not going to be acceptable as it would just take too much time to do each bend. After careful consideration as to what it would take to build the bender and how much time it would take to build it and make the dies, I decided it would be easier and less money to just buy one. Now that it was purchased and mounted, I could start making the frame.

Cutting the tubing to length and making the bends was fairly simple and was able to be finished in one day (Fig. 1). However, cutting the notches and getting the tubing to fit correctly was another whole day. I discovered real quickly how important a tubing notcher is and before I start another frame I will have to purchase a good one. Using my drill press proved to be a real challenge, its pretty old, but with the use of a grinder and some files, the notching was done and the frame was ready to be tack welded together.

Before I could tack weld it together though I had to create the axle plates for the rear, these were cut out of plate steel and put on the mill together. This way the slots for the axle were cut at the same time ensuring they were the same. Next a slot was cut into the front of the axle plates and a chain adjuster was welded in place. Now the tack welding could be finished (Fig. 2). Once the frame was tack welded and I was sure that everything had stayed square I got to find out how well my frame jig actually worked. I was able to rotate the entire frame 360 degrees (Fig. 3) so that all welds were done at the most optimum angle. This proved to work really well and made welding the frame real easy. I made sure to weld a little on each side at a time to reduce how much twisting would occur.

Now that the frame was welded and off the jig it was time to start making the motor mounts. I was able to find a set of cases from a 1978 CB750 to use as a mock up motor, this made getting the mounts in the right location a whole lot easier than trying to use the assembled motor. The only draw back is that the 78 and 79 have slightly different motor mounts. I was able to use the 78 for the bottom mounts (Fig. 4) and get them welded in before I had to mount the actual motor for the top mount.

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