I originally acquired this Bultaco Alpina 175cc M98 from a guy Colorado. Engine numbers match the frame but it had seen its better days. In March 2021 I completed a the restoration with most of the parts purchased from Hughs Bultaco in Craryville NY. Now that it is ready to ride I am planning its first vintage ride in western North Dakota this April.
1973 Bultaco 175 Alpina 
M98 as acquired and before restoration
Restoration progress and details
The process started with striping everything off the bike down to the bare frame. The FRAME, swing arm and small painted parts were sandblasted in prep for new silver frame paint. The fiberglass TANK was sealed with Caswell Epoxy tank sealer which is a two part epoxy. I have found this to be the best product for sealing these tanks. Once the tank was sealed the tank was sanded, pinholes filled, primed and painted with the correct mix of PPG base clear automotive paint. The ENGINE was completely disassembled for inspection, all bearings and seals replaced, new piston and rings fitted to the newly bored and honed cylinder. The EXHAUST port threads were beyond use. The fix was I machined the exhaust port round and made a threaded steel insert that I pressed and pinned into the port. I also made up a new exhaust nut which is made of stainless steel. This nut is a duplicate of the original but will be much tougher. I did not have a rear final muffler so made a removable turn out pipe to keep the exhaust away from the wheel. Fenders are tougher stainless steel versions I had acquired some years ago. TIRES are Bridgestone Battlecross X30 100/100-18 rear and 80/100-21 up front. Rear wheel odometer gear box was removed and I replaced with a spacer I machined for the correct offset. All the other normal stuff was also done, new cables, seat cover, wiring, points, condenser, rubber parts, chain, sprockets, etc….
