The tranquilizing effect of this project is a godsend. While I run near redline most of my waking hours, when I’m wrenching I am able to roll back the throttle and idle for a while. The din of Santa Monica Boulevard traffic fades from my awareness as I chase damaged threads and tend to stuck fasteners. Dull chrome has been made shiny again with steel wool, plastic and painted pieces wiped clean, and corroded bits rubbed down with Scrotchbrite in preparation for painting. 
The muffler, cylinder, intake manifold, and fork lowers were given several thick coats of hi-temp matte-black paint, after which they look 20 years newer. The finish on the MB’s elongated fuel tank, part of which extends under the bench seat, is in good shape, but the same can’t be said for the inside. I twist off the cap and peer in. Ooh, not very encouraging; it’s rusty. There is crusty rust, chunky rust, and dusty rust, and no matter how long I shake it, it keeps pouring out. It’s like the Horn Of Plenty, except with iron oxide, and it’s a gas tank. There’s a company called Rusteco near the MC offices here in El Segundo that claims to have an effective, non-toxic rust-removal treatment. I’ll have to give them a call.
After several decades in the sun the front brake reservoir has turned into flaky, porous, crumbling mess. Contaminated brake fluid has done a number on the master cylinder internals, and the single-piston front caliper is seized. Thank goodness for Ebay. A quick search yields relatively cheap rebuild kits for both bits.
I picked up a Haynes manual to guide me through the inspection process. The book’s detailed schematics have helped me compile a list of “soft” parts that should be replaced. Huntington Beach Honda received an order yesterday for the various gaskets and seals I’ll need when I tear down the engine. eBay has proven to be a great resource for used and NOS parts, some I need, some I’d just like to pick up because they’re in better shape than the pieces I have. I also stumbled across Perk LLC (www.PerkLLC.com), which is a treasure trove of performance parts for the MB5 and other small two strokes. Hot-rodding the MB is certainly a temptation, but I need to get it running first! If the stock cylinder is serviceable I’ll go ahead and use it to get the engine running properly before doing any modifications.
As it sits the previous owner had 0.01-inch skimmed off the head, which should help with acceleration. Other tasty treats that came with the MB include a new piston, rings, and small-end bearing, clutch plates, an unidentified performance exhaust, and a few NOS gaskets.
I still need to find tires for the MB’s 18-inch Comstar mags, a headlight, battery, chain, and front brake pads, among other things. While I wait for the engine gaskets to arrive, I’ll delve into the engine and see how things look. Stay tuned.
Resources:
Haynes Manuals
-Invaluable technical information and diagrams.
www.haynes.com
(800) 242-4637
Huntington Beach Honda
-Various OE parts such as gaskets, grommets, and seals.
www.hbhonda.com
(714) 842-5533
Just arrived? Check out earlier posts from the series:
Mechanical Meditations: Part I
Awesome story, and a very inovative solution! Nice work. I can’t wait to get this thing running, although I must say I really enjoy working on it.
Regards,
Ari
Hi, Ari.
I, too, have an MB% project bike. I am in love with that little motorcycle. I have an ’87 Sportster as well, but the little MB5 gives me perhaps even more joy to work on than the Sportster.
Anyway, I thought I would drop a line and tell you about my gas tank adventure. My tank was completely rusted through in several spots, and I had trouble finding a cheap replacement. I only found one tank on ebay, and it sounded almost as badly rusted as mine, and they wanted fifty bucks for it. What I ended up doing is I bought a small half gallon capacity plastic gas tank for the MB5. I cut out the bottom of my existing tank, and the little plastic one sits inside the original, and the gas cap thread come out of the original hole. It worked out more perfectly than I could have ever dreamed.
I know half gallon capacity is not much fuel, but at least I don’t have to worry rust anymore. And that little bike can run for a surprisingly long time off of half a gallon.
I can send pics if you are interested in seeing how it turned out.
I bought mine for twenty five dollars. I was driving down the rode one day and saw it sitting on a street corner with a cardboard for sale sign on it. It had no carburetor and the gas tank was sitting on the ground next to it in rusted pieces, but I never thought twice about buying it.