Tank to transit system... and authentic sound...

The insides looked like turn of the century sewer pipe.

"Be it no concern, point of no return- Go forward in reverse - This I will recall - Every time I fall - I'm free - Setting forth in the universe - Out here realigned - A planet out of sight - Nature drunk and high - Oh I'm free - I'm free..." --Eddie Vedder:
I want to hear the engine on my 1974 Honda CB360 run. There's no need for gears, brakes, and lights at this point. I just need first to hear it choke a bit, perhaps to growl, and if I am lucky... purr. It will be a first step, a hopeful step, to move me to where I can feel the wind in my hair...

"An injured lion still wants to roar." --Randy Pausch: There is something lovely (some would say "sexy", but I am not sure I concur) about the sound of a well tuned engine. It's the sound of metal moving/clicking in a synched rhythm that makes for a complicatedly layered sound experience. It does not need to be loud for me, just rhythmic, harmonic...

Fakery: Good engine noise holds such an allure for some that new, more efficient (and still powerful), quieter engines have sound "piped" in for the driver to hear:

Fake engine noise has become one of the auto industry’s dirty little secrets, with automakers from BMW to Volkswagen turning to a sound-boosting bag of tricks. Without them, today’s more fuel-efficient engines would sound far quieter and, automakers worry, seemingly less powerful, potentially pushing buyers away. 

Softer-sounding engines are actually a positive symbol of just how far engines and gas economy have progressed. But automakers say they resort to artifice because they understand a key car-buyer paradox: Drivers want all the force and fuel savings of a newer, better engine — but the classic sound of an old gas-guzzler. 

“Enhanced” engine songs have become the signature of eerily quiet electrics such as the Toyota Prius. But the fakery is increasingly finding its way into beefy trucks and muscle cars, long revered for their iconic growl. 

For the 2015 Mustang EcoBoost, Ford sound engineers and developers worked on an “Active Noise Control” system that amplifies the engine’s purr through the car speakers. Afterward, the automaker surveyed members of Mustang fan clubs on which processed “sound concepts” they most enjoyed. --Washington Post

Scrubbed clean of almost all internal corrosion.

Analog, not digital: When my CB360 runs, the sound will be authentic. It will not be deep like a Harley; it's a small-guy bike. It should sound and feel exactly like the time it is from, the early '70s. Attitude will trump muscle and feel like Steve McQueen looks in The Great Escape. The sound will speak to me in slap-tap click. And I will listen patiently... Once we get it to run, then we can attend to the niceties of shifting, and stopping, and seeing in the dark...

Someday...: Therefore, eventually, I will need the pistons to move and compress, and plugs to spark brightly, and fuel to be mixed properly with the right amounts of air. But before we attend to all this (and it is in the works already in Kevin's garage) I need to establish the most simple of elements, a reservoir to hold my fuel and a transit system to deliver the fuel to the carburetor (where the cool stuff starts happening)...

Plastic Liner Product

“ANYTHING will burn with enough gasoline and dynamite.” ― Robert A. Heinlein: The 2.9 gallon fuel tank was filled with rotten gas and gobs of flakey rust when I brought it home. The long story of cleaning the tank takes place over weeks of treatment with different acids, abrasives, shaking, sloshing, and back-wrenching tank gyrations. It is about frustration and a worry that "no tank" means "no bike" and therefore a dream deferred. A new tank can run hundred of dollars (not a number range to be uttered near the "project bike" budget-meisters).  The shorter story of cleaning the tank goes like this: after several vinegar soaks with sheet rock screws for shaking agitation, "Iron Out" with pea gravel as an agitator and funny looking lint-trap brushes for scrubbing, and an unknown "etcher" chemical that most likely causes cancer if ingested (only in California though), the tank came clean. The end. 

Clean Kreem: We finished the tank clean-up and restoration process with repeated applications of a plastic lining product called Kreem. Impervious to all fuels and man-made products except Methyl-ethyl-death, the Kreem liner should keep my 42 year old dented fuel tank doing its job well for the rest of the bike's life. The total cost of all acids, chemicals, and liners came in under $75. Add to that a new gas-cap gasket to replace the completely rotten old one and... hope restored.

Dirty Petcock

"That's been one of my mantras - focus and simplicity. Simple can be harder than complex: You have to work hard to get your thinking clean to make it simple. But it's worth it in the end because once you get there, you can move mountains." --Steve Jobs: The second part of the tank clean up was to address the petcock (fuel cock) valve that drops from the underside of the tank, allowing fuel to be pulled from the tank to the carburetors. It is a simple device with two intakes, one for regular operation, and one for low-fuel "reserve" operation. The latter is a screened tube that offers an initial filter to keep any tank-junk from getting into the combustion system. There is a second, finer filter that treats all fuel leaving these two inlets before moving through separate fuel lines to the dual-carbs. Not a complicated device, but essential that it can filter the fuel and allow it to flow properly. This was a job for a can of parts cleaner solvent. 

The 350 and 360 parts both clean but with no reserve filter.

Oh, to be clean: There's nothing like taking a long soaking bath in something that strips away all the gunk that years of use and neglect can cause... The same can be said of motorcycle parts. Parts cleaner solvent made quick work of all the rust, grime, caked fuel... everything... including any "shine" that was left on the metal. And the old part still looks aged, but no longer gross. Simple and functioning. Beautiful...

Old is sometimes better than new: In addition to my CB360 (blue) tank, I have a CB350 (orange) tank that is locked shut, and filled with more shellack and rust than air. Thus I have two petcocks and hoped between the two of them I might get one really nice restored one. A new fuel valve of this type costs $35. So if I am able to get the old ones happy, I save a little money to put toward rubber or cables, and I keep the 1974 look on one more part on this bike...

Clean, working, filtered petcock.

A little creative thinking: The reserve level filter was completely destroyed in the cleaning process. It is part of the unibody construction on the original so there are no spare parts out there. I scoured the interwebs for makeshift push-in plastic strainers that might work... to no avail. Small engine fuel filters that had nipples the right size were too bulbous above. I needed a straight line with mesh construction. The answer lay in a roll pin hammered into the old filter hole and a need for something to keep the gunk from getting into the fuel line. Kevin, my primary guide in this bike repair, helped with a small circular mesh screen that he artfully folded to cap over the roll pin. A little solder and my filter was all set. $10 of new fuel line and eventually an inline filter for added protection and the tank-to-carburetor part of the project is done. No profound symbolism here. No deep understanding of life beyond the simple, clean need to bring fuel from a reservoir to power the machine that takes the man down the road to keep wind in his hair. Onward to the moving parts...