Part XII: Head Work

Mechanical Meditations

Sudco has a sack of main jets waiting for me at their Commerce office, but I won't have the time to swing by until later in the week. With nothing on the agenda yesterday afternoon and a burning desire to work on something, I decided to pull the engine (a 10-minute process) and give the top end a go-over.

You see, a couple weeks ago I rediscovered my father’s copy of A. Graham Bell’s 1983 masterpiece _Two-Stroke Performance Tuning. _As the title suggests, the book is a comprehensive guide to engine building and tweaking, with chapters detailing everything from ignition curves and combustion chamber design to carburetor tuning and exhaust fabrication. I squashed some solder and measured squish with various gasket combinations, added water by the 1/10th of a cubic centimeter to determine compression ratio, and marked the rotor for future ignition timing experimentation. My measurements show that the MB5 is on the reliable end of the performance spectrum, as in there is a lot of room for improvement. I know there’s not a lot of power to be squeezed out of a 64.5cc air-cooled two-stroke, but I’m looking forward seeing just how fast I can get the thing to go.


Motion Pro
-Specialty tools, custom cables, and replacement parts

Bikemaster -Quality affordable parts

Dr. John's Motorcycle Frame Straightening
-Singlehandedly responsible for putting the MB5 project back on track!
Dr. Johns **
Sudco International
-Replacement electrical components, Mikuni VM22 carburetor, perveyor of quality replacement parts for vintage bikes
Sudco International **
Michelin Tires -Gazzelle moped tires

Caswell Plating
-Epoxy tank sealant - the best there is! 70cc kit. Moped parts superstore.

Perk LLC
-Case gaskets and technical advice. Supplier of hard-to-find moped parts. (317) 371-8530

Rusteco-Rust removal treatment for the MB5's gas tank. (800) 787-8326

Haynes Manuals
-Invaluable technical information and diagrams. (800) 242-4637

Huntington Beach Honda
-Various OE parts such as gaskets, grommets, and seals. (714) 842-5533

Performance tuning the MB5
Performance tuning the MB5Motorcyclist
Performance tuning the MB5
Performance tuning the MB5Motorcyclist
Performance tuning the MB5
Performance tuning the MB5Motorcyclist