Bultakenstein’s motor has returned from its West Coast spa vacation, looking very healthy. True to the spirit of the bike, it’s a mix of parts. The cylinder I sent to Ralph wouldn’t work with the crankcase transfer openings, so he found me a cylinder from an earlier Pursing 360 (Model 112, 1972-1973) and an Alpina 350 head. The fins are cut down on the right side of the head for the Alpina’s high exhaust, but that’s no big whoop because I eventually hope to swap out the head for a modified Husqvarna radial-fin head.

Ralph offered to buff up the cases and engine covers, but I declined, because I intend to paint them. Originally, I planned for the entire engine to be satin black, mimicking the look of the final series of Bultaco road bikes. However, I probably won’t be able to swing a chromed expansion chamber, and with a black engine, black frame, and black exhaust, the whole lower half of the bike becomes a bit muddled and dull.

Metralla GTS 370 factory prototype, circa 1980–81

Therefore, my current plan is to try and replicate the appearance of the Montjuïc 360 prototype in its earliest iteration: bare alloy cases with satin black side covers in a silver frame.

Here’s a crude visualization I quickly slapped together. I’m not sure why I had assumed throughout this project that Bultakenstein would have a black frame; I think silver would lighten the whole appearance of the bike nicely and help the dark engine covers pop.

A lot of Bultacos had silver frames over the years, both dirt and street bikes, so the look is appropriate to the brand.

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