Part XIII: Meditation Time Is Over

It’s been quite a while since the Mechanical Meditations blog has been updated, because instead of wrenching on and writing about the MB5, I’ve been riding it! The bike has been tuned and registered (temporarily, anyway) and has carried me to work in shrieking style a dozen times in the past few weeks. It’s even accompanied me to the track and served as an ultra-cool retro pit bike.

[In my last post I had yet to settle on a suitable main jet. I’ve since jetted the bike – and soured my relationship with my neighbors after doing countless full-throttle jetting runs around the block. The MB sounds like an enormous Jurassic-era mosquito on crack! To help me in the tuning process I installed a Trail Tech TTO temperature gauge, which positions a copper sensor ring under the spark plug and registers combustion chamber temperature. It’s a very cool device, and at $35 it’s about 1/10th the price of overheating the engine. After running the bike without filtration for the first few rides, I finally picked up a K&N unit to purify the air before it enters the MB’s crankcase. Before taking the bike on public streets I bolted an LED light bar from the Aerostich catalog on the back of the seat and I installed a set of EBC sintered brake pads in the front caliper.

As the main jet size came down throttle response and power progressively increased and the plug color lightened. It’s all dialed in now, and while acceleration is far from scorching, what the MB lacks in performance it makes up for in character and style.

Getting off the line ahead of traffic takes a fistful of throttle and careful manipulation of the clutch. You nail 3rd gear by the time you cross the intersection, and then it’s time to settle into 4th and cruise. There’s no throttle response below 6000 rpms, and the power band is all of 2500 rpms wide, but damn its fun to chase redline and row through the gearbox. Keep it pinned for long enough and the bike eventually flirts with 60 mph, but it’s much happier cruising at 50 mph, which is the top speed for a stock bike.

Feast your eyes on the accompanying pictures of the completed project. They come courtesy of Super Streetbike's John Zamora and Source Interlink Media's fantastic photo studio. I had a half-can of Apple Red spray paint left over from my CB350 vintage race bike, so I pointed the nozzle towards the MB just to get some color on it. The bike deserves a better paint job and will eventually get it, but for now she's essentially done. Building the bike has been cathartic and entertaining, but now the real fun begins. Meditation time is over, now it's time to ride!

Resources:

EBC Brakes
Fresh brake pads to optimize the MB's single-disc front brake
ebcbrakes.com

K&N Air Filters-Superior air filtration for a freshly rebuild engine
knfilters.com

Trail Tech-TTO temperature gauge
trailtech.net

Aerostich Rider Wearhouse
7 inch LED integrated tail light, brake light, and turn signals
aerostich.com

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

Bikemaster -Quality affordable parts
bikemaster.com

Dr. John's Motorcycle Frame Straightening
Singlehandedly responsible for putting the MB5 project back on track!
drjohnsmfs.com

Sudco International
Replacement electrical components, Mikuni VM22 carburetor, perveyor of quality replacement parts for vintage bikes
sudco.com

Michelin Tires -Gazzelle moped tires
michelinmotorcycle.com

Caswell Plating
Epoxy tank sealant - the best there is!
caswellplating.com

Treatland.tv
Malossi 70cc kit. Moped parts superstore.
treatland.tv

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

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

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

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