Evo Sportster project started October 2024,

After receiving quite a few requests for a good CAD
model of an Evo Sportster drivetrain, I bought an empty
unit from 1990 and will show the whole process here:

 
 
 

As mentioned above I bought an empty Sportster 883 drivetrain from 1990, so the first job was stripping and cleaning it. After getting the worst gunk off with degreaser there was (ofcourse..) one stud that refused to come loose and finally broke off. I welded a nut on the remaining part of it and finally got it out. Then I took the crankcases to Blink Wetblasting and got them back perfectly clean, time to start scanning!

The pictures above are screenshots from the scanner software, I am using an Einscan Pro2XPlus on a Tripod

 

I am not a big fan of freehand scanning, it is not accurate enough. For the right crankcase for example I took 37 separate scans with the scanner on a tripod. These 37 scans were combined into a single large pointcloud of 17826339 points (see picture above, left), this is then exported as an STL file where all the dots have been connected with millions of little triangles. (see picture above, right) Scanning took about 3 hours for this part. The STL file can be simplified where the number of triangles can be reduced on the flat areas for example. Then the fun part starts where the millions of triangles are replaced by clean CAD solids. That right crankcase in the last picture on this page is the end result. For the CAD guys out there, right crankcase has 215 features now, I will not be modeling the insides as these will not be visible and I want to keep the filesize manageable. And this was already about 12 hours CAD work for the first part...