Yamaha HX90 Motorcycle

Yamaha HX90

This is the third free motorcycle kit published on the web by Kozin. As built it consisted of an 11-page PDF file:

9 pages for a red HX90,
1 page of alternative parts for an orange AX125,
1 page with alternative colours (blue HX90 and mauve AX125).

The CG rendering of the HX90 was put up in October 2006. A first unfolded file, with no tabs or textures, and many parts missing, was posted in February 2007. However, at about that time there were several posts elsewhere on the site which (as far as I can tell using machine translations) suggested that his work (and possibly home life) had become much more demanding. There was a long gap until June, when photographs of his test build started appearing, together with updated versions of the parts file. Finally, in September, he declared it finished but said (I think) that there would be a wait for any assembly instructions. If you had completed the previous models this one would not be difficult, however.

The above was written in December 2007. It is now December 2008, and I have just completed the model. It has proved to be quite tricky.

The primary problem is the lack of assembly diagrams or instructions. The majority of the parts are, of course, quite easily identifiable, but a proportion were rather enigmatic. The rather small and not very numerous photographs of the prototype build helped, as did the sparse text on the parts sheets. Unfortunately for me this text is in Japanese, and the PDF file is locked against text extraction, so I had to learn how to transcribe the characters in order to get them translated. The great majority are Katakana (syllabic characters) which were not too hard to pick out from the Windows Character Map tool. For the few Kanji (pictograms) I had previously found WWWJDIC and Tangorin. Both of these allow the user to search for pictograms using combinations of basic elements. Even spotting the elements is not always easy for the linguistically-challenged, but I got quite a lot of practice when working on the Eastern Serow 225.

The other main difficulty is that the parts are clearly unfolded from a polygonal model, and show irregularities around their connecting edges which mask their true shapes. This is particularly noticeable on small cylindrical and conical pieces - the headlight and indicator lights, and the various pipes in the frame, exhaust and handlebars. I think that a lot of these oddities would have been ironed out had Kozin been able to spend some time preparing the model for final release.

Like the two earlier models, this one has been recast as a Pepakura file, so many of the problems have been eased, though the lack of assembly instructions still presents a problem. The new version comes only in red, rather darker than the one shown.

Finally, a self-inflicted problem is that as usual I chose to make the model approximately half-size. In fact the original scale is roughly 1:8, so I scaled by a factor 4/7, to match the majority of my motorcycle models. I also chose to make the wire wheels using thread rather than the inevitably over-sized paper spokes provided.

Right side Front right
Front left Left side
Rear left Rear right

Updated November 2021