After a disasterous first attempt at building a Pro-Stock skate Mac from the case of our trusty late 90's G4 'Sawtooth' Powermac we decided to step-up our efforts and debut the MOTO G4 series! This involved completely gutting the case and building it onto a mini-motorbike frame. We named the project 'Buran' after a space-shuttle the Russians spent billions constructing, but ran out of money before it ever flew. (NB: The bike has ridden once though so maybe 'Spruce Goose' would have been better.)

The pics below catalogue the ongoing conversion process of this astonishing machine from retro-Snapple to superbike.

This was the original concept on which we based the Mac-Moto - bicycle steering and the engine inside the Mac case. Turned out we were using an air-cooled engine so we ended up mounting the engine just in front of the case even though it would have fit inside. I would not advise fitting the engine completely inside the case unless you have a good duct system or a water-cooled motor.



First we removed all the plastic panels and cut apart the Mac case to fit the bike frame. This involved stripping everything inside the case, including the metal drive-tray and the Airport, down to a bare metal box. To make the hinged side-panel lift up instead of down we had to turn the case upside-down to fit onto the bike. This makes the plastic panel-fit not exact, but close enough to screw back on. Rather than have the back of the Mac-case on display at the back of the bike, with all it's sockets and fan holes, we also decided to turn the Mac round so that the smooth case-front would be on show.



Next we cut a large gap into the fixed case-side to allow a small amount of room for the rear bike fork and the brake caliper. Then we cut away the CD-drive housing, now at the case-bottom, and a bit above it to form a rear wheel-arch. The first picture shows the finished bare-metal case. Another hole is cut a few inches above the wheel arch, which sits just behind the exhaust when on the bike. So that the air-cooled engine could breathe, the Mac had to be mounted just behind it and this meant the entire steel back-panel of the case had to be cut away, as can be seen in the second picture above.

With the case prepared, we built a rectangular wooden sub-frame for the Mac to sit on securely and evenly, rather than having it bolt straight to the slim metal bike-frame and attatched it to the rear of the bike-chassis. The wooden sub-frame also lifts the Mac up by 2 inches for ground clearance and to make the seated-position higher and more natural. We then moved the Mac-case down into place, slotting the gaps we cut over the rear bike-fork and brake, bolted it in place and began to re-fit the plastic panels.



As the case has been flipped and reversed to fit on the bike, with the case-bottom now at the top, the fit of the plastic panels is not exact, but they will go on snugly with a bit of work - mainly milling the inside face of the panels flat because the holes that fit the pegs are now in the wrong place, though the position of the vital screw-holes are unchanged.

Now we turned our attention to the engine. We had mounted the Mac-case just behind the motor so it didn't trouble the engine-cooling. Unfortunately we found that the air-inlet to the carburettor is mounted at the back of the engine and therefore still trapped inside the metal box. We used a short quarter-turn PVC pipe and a flexible stiff-rubber hose to make a duct to force cool air from the front of the bike into the carburettor, pictured below. We left a gap in the end between the duct and the carb. inlet, rather than having it sealed, so the bike would'nt choke on tickover having to suck through the pipe.



To fit the Mac onto the wooden sub-frame we had to move it back at inch and this meant the exhaust was now an inch too far back. To stop the case from filling with smoke we cut a short chrome tailpiece to extend the pipe, in the left pic below, which looks much nicer anyway. (..or will when the drive bezel is found -.-) Next we cut the old bike fuel-tank cover down to fit the case handdle, shown in the other pic below, and sprayed it grey, which is better at least than orange. We also forgot that we moved the case back, leaving an inch gap. Oops.



As a final touch to the bodywork we cut up an original model Apple Pro keyboard and sanded it into a nice curve to form a windscreen for the bike. The bottom case-handles across the front forks will soon house a headlight unit we've made using super-bright LEDs. The MOTO G4 is now good to roll and ready for testing, although we're gonna throw on a few tacky styling bits.



Nearly finished! A little strengthening and a bit more styling and this baby is ready to roll!