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Howdy from Texas everyone! Haven't been on here in a while so I figured we'd better poke our head in and offer a little eye-candy...
We were recently offered the opportunity to develop a production hard tail or rather "REAR LOOP" for the legendary KZ750B model. This is the old TWIN that is sometimes elusive to find and fun to chop and a BLAST to ride!!!
This effort began with Mr. Paul Mader out of Green Bay, Wisconsin who was gracious enough to offer his entire frame as a test-bed for development.
We are happy to inform Mr. Mader that his KZ750B project has turned out even better than originally expected!
Here's the install:
We began with the original frame:
We were able to design the REAR LOOP to accommodate approximately 4 inches of drop giving us a finished rake of 32 degrees (plus-minus).
Notice the temporary jig we fabricated in order to accurately design the heavy-duty rear engine mounts. This jig IS NOT NECESSARY for the rear loop installation by the builder! It's simply for design and development purposes... We began by marking our cut line 1/2" from the kick stand bracket and transferred the same mark directly across to the adjacent side.
Our next cut line was applied to the main backbone 12 inches south of the neck tube. We also transferred the same line across the smaller box frame tubes as well...
Once the backbone and box frame rails were cut, we then proceeded to clean up the remainder of the small box-frame tubes where they connect at the neck tube...
This procedure was taken carefully with care NOT to damage the neck tube. It's not necessarily a problem if you slightly scar the gusset or tube are immediately surrounding this area. A 10ga gusset will be welded in place in a later procedure. Because of this, it is NOT necessary to fully remove all the box-frame tube. You can leave any material that is inside the space that will be covered by the new gusset...
At this point, about two-thirds of the weight has been removed and we are ready to move on to the next procedure...
We started preparing the cut ends to be welded by sanding the INSIDE and OUTSIDE of the frame rails. We also drilled 3/8" plug holes under the two lower frame rails and on top of the backbone. These holes were drilled about 1/2" from the cut edge...
Next... We began by sliding the rear loop (MK28) into the KZ backbone. This had to be done FIRST before attempting to fasten the two lower rails of the frame...
With a mark placed 2" down the backbone, we positioned the MK28 to the mark...
At the same time, we confirmed that our lower rails had approximately 1/4" of material gap appropriate for a proper weld...
Once the two units were in position, we checked alignment by taping a string to the TOP CENTER of the original backbone as close to the neck tube as possible. Using this string, we could adjust the MK28 left or right until the string showed accurate alignment down the center of the original backbone and the MK28 backbone as well...
At this point, we felt it was safe to tack-weld the rear loop in place!
After verifying that everything was still in place and aligned, we began the final welds. We started each weld at the PLUG location, filling it flush with the surface of the frame rail. Full penetration is important when "plugging" these holes!
We also laid a "healthy" bead to fill the small gap between the interior of the existing KZ backbone and the new MK28 backbone. As this area rests beneath the gas tank, we didn't worry about the appearance of the weld... We just made sure it would hold!
After repeating this process at the two lower frame rail connections, we were happily left with a completely modified KZ750 Twin frame ready for the gussets and motor mounts!
Remember that ENGINE JIG we fabricated earlier? Well... Now it comes into play! Since we do not have the motor in-hand, we had to use our engine jig to design and fabricate the rear motor mounts. They are fabricated from 3/8" mild steel and are more than hefty enough to support the KZ750B! With the motor (or jig) in place, we can fasten the mounts to the motor making sure that the mounts are properly installed with precision. We are letting Paul Mader complete this process since he is still in possession of his motor.
THE FINAL DETAIL!
For those of you who wish to keep your steering lock mechanism, this is what we did... We traced one of the supplied neck gussets on a piece of cardboard. We then trimmed the cardboard until it had an adequate notch for the steering lock...
We then traced the cardboard onto the supplied neck gusset...
Secured in a vise, we were able to trim out the small notch using the outer edge of an abrasive cutting / grinding blade. You have to be patient and careful not to go outside your lines when performing this procedure...
With the new neck gusset notched, it is now ready to weld in place!
And there you have it! We are done with the gussets and Mr. Mader's frame is ready to take a trip from Texas to Wisconsin!
We hope to see what Mr. Mader does to complete and personalize his 750B build and we will certainly post any update photos soon as we receive them! Thanks again for visiting this thread and if you have any comments, feel free to PM away!
Cheers!
David-
Voodoo Vintage
We were recently offered the opportunity to develop a production hard tail or rather "REAR LOOP" for the legendary KZ750B model. This is the old TWIN that is sometimes elusive to find and fun to chop and a BLAST to ride!!!
This effort began with Mr. Paul Mader out of Green Bay, Wisconsin who was gracious enough to offer his entire frame as a test-bed for development.
We are happy to inform Mr. Mader that his KZ750B project has turned out even better than originally expected!
Here's the install:
We began with the original frame:
We were able to design the REAR LOOP to accommodate approximately 4 inches of drop giving us a finished rake of 32 degrees (plus-minus).
Notice the temporary jig we fabricated in order to accurately design the heavy-duty rear engine mounts. This jig IS NOT NECESSARY for the rear loop installation by the builder! It's simply for design and development purposes... We began by marking our cut line 1/2" from the kick stand bracket and transferred the same mark directly across to the adjacent side.
Our next cut line was applied to the main backbone 12 inches south of the neck tube. We also transferred the same line across the smaller box frame tubes as well...
Once the backbone and box frame rails were cut, we then proceeded to clean up the remainder of the small box-frame tubes where they connect at the neck tube...
This procedure was taken carefully with care NOT to damage the neck tube. It's not necessarily a problem if you slightly scar the gusset or tube are immediately surrounding this area. A 10ga gusset will be welded in place in a later procedure. Because of this, it is NOT necessary to fully remove all the box-frame tube. You can leave any material that is inside the space that will be covered by the new gusset...
At this point, about two-thirds of the weight has been removed and we are ready to move on to the next procedure...
We started preparing the cut ends to be welded by sanding the INSIDE and OUTSIDE of the frame rails. We also drilled 3/8" plug holes under the two lower frame rails and on top of the backbone. These holes were drilled about 1/2" from the cut edge...
Next... We began by sliding the rear loop (MK28) into the KZ backbone. This had to be done FIRST before attempting to fasten the two lower rails of the frame...
With a mark placed 2" down the backbone, we positioned the MK28 to the mark...
At the same time, we confirmed that our lower rails had approximately 1/4" of material gap appropriate for a proper weld...
Once the two units were in position, we checked alignment by taping a string to the TOP CENTER of the original backbone as close to the neck tube as possible. Using this string, we could adjust the MK28 left or right until the string showed accurate alignment down the center of the original backbone and the MK28 backbone as well...
At this point, we felt it was safe to tack-weld the rear loop in place!
After verifying that everything was still in place and aligned, we began the final welds. We started each weld at the PLUG location, filling it flush with the surface of the frame rail. Full penetration is important when "plugging" these holes!
We also laid a "healthy" bead to fill the small gap between the interior of the existing KZ backbone and the new MK28 backbone. As this area rests beneath the gas tank, we didn't worry about the appearance of the weld... We just made sure it would hold!
After repeating this process at the two lower frame rail connections, we were happily left with a completely modified KZ750 Twin frame ready for the gussets and motor mounts!
Remember that ENGINE JIG we fabricated earlier? Well... Now it comes into play! Since we do not have the motor in-hand, we had to use our engine jig to design and fabricate the rear motor mounts. They are fabricated from 3/8" mild steel and are more than hefty enough to support the KZ750B! With the motor (or jig) in place, we can fasten the mounts to the motor making sure that the mounts are properly installed with precision. We are letting Paul Mader complete this process since he is still in possession of his motor.
THE FINAL DETAIL!
For those of you who wish to keep your steering lock mechanism, this is what we did... We traced one of the supplied neck gussets on a piece of cardboard. We then trimmed the cardboard until it had an adequate notch for the steering lock...
We then traced the cardboard onto the supplied neck gusset...
Secured in a vise, we were able to trim out the small notch using the outer edge of an abrasive cutting / grinding blade. You have to be patient and careful not to go outside your lines when performing this procedure...
With the new neck gusset notched, it is now ready to weld in place!
And there you have it! We are done with the gussets and Mr. Mader's frame is ready to take a trip from Texas to Wisconsin!
We hope to see what Mr. Mader does to complete and personalize his 750B build and we will certainly post any update photos soon as we receive them! Thanks again for visiting this thread and if you have any comments, feel free to PM away!
Cheers!
David-
Voodoo Vintage
Ha ha ha....
We have to keep our products within our customers' budget and ability. And believe me... That's why they love us so much!!! 
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