Billet clip-ons and top yoke - Suzuki T250J

I wanted to create something to my bike with abrasive water jet cutter that we have at our university. I had already machined a billet out of recycled aluminum which was perfect for a top yoke. Size of the billet was 200 x 200 x 23 mm. 

I had previously purchased a pair of billet clip-ons from ebay which I used for an inspiration when I started to design the top yoke. Handlebars sit in a 10 degree angle and they are made out of 22 x 380 mm aluminum tube. Inner diameter of the tube is 16 mm.

Pair of clip-ons I bought from ebay which are meant for 
34 mm tubes. Outside diameter of clamp is 49 mm.

I wanted to implement features from the clip-ons to the design so I designed four symmetrical triangle shaped holes which follow outlines of the top yoke. I also wanted the outside diameter (49 mm) to match.

I used two different softwares to create necessary tool path for the abrasive water jet cutter. Basic outline of the top yoke was designed with CATIA V5. I used CATIA's part design workbench to create a 3D model which I then moved to drafting workbench to create a DXF file. Tool path and DNC file was created with IGEMS.

3D-model of the top yoke without machined features.

Preview of the DXF file.

Last step was to machine all the necessary features with a vertical milling machine and finish the outside surface with flap wheel with shank. I used a round ceramic grinding stick with shank to smooth the triangle shaped holes. I felt that polishing would have taken too much time so I used a finishing pad like Mirlon to get a brushed look.

Workshop drawing.

Top view.

Bottom view.

T500 swingarm swap - Suzuki T250J

I was already planning to fabricate a longer swingarm to my Suzuki until I came across a T500 project thread in dotheton.com which displayed a T500 swingarm and started to wonder if one would fit to my T250. 

I started comparing part numbers from T500 and T250 swingarm and rear wheel parts lists and realized that most of the bushings and spacers for swingarm axles were same. Part numbers for different rear wheel parts seemed to match as well.

I made a want to by add for T500 swingarm to our local Finnish veteran motorcycle website/forum and quickly came by one. Same guy who sold me the GT250 fuel tank had one for sale. He also recommended that I buy a rear brake cable as well since it's a bit longer in T500 than T250.

Suzuki T500 swingarm and axle,
rear brake cable and oil tank.

Comparison of T500 and T250 swingarms.

Overall length of T250's swingarm is approximately 385 mm and T500's 505 mm (axle to axle). Width of both axle's fastening points are same in both swingarms (182 mm for swingarm axle with bushings in place and 195 mm for rear wheel axle (inner dimension)). Fastening point in frame is 190 mm wide (inner dimension).

Comparison of T500 (upper) and T250 brake cables and swingarm axles.

T500's rear brake cable's housing is 445 mm long and T250's 310 mm. Both swingarm axles are 14 mm thick. T500's axle is 249 mm long and T250's 225 mm. Threads are 25 mm long in both axles.

Fastening points for rear shocks in T500 swingarm are a bit wider than the ones in T250 frame (224 mm vs 208 mm) so I had to turn couple of spacers to get rear shocks lined. Other than that swingarm fitted right in place.

Dimensions for spacers,...

...turned,...

... and in place.

Rear shock installed.

Closer side view.

Overall side view of my Suzuki T250 with T500 swingarm and oil tank.
Fuel tank and seat are from GT250.