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Fuel system.
Tank cleaning & protection methods. Premium vs. regular. Fuel additives.
Fitting other tanks...seats & fitment with various tanks. Pesky
rusted/frozen screws on seat hinges. Throttle & choke cables.
FUEL HOSES. Tank sealants & liners.

© Copyright 2018, R. Fleischer

Ref:  http://bmwmotorcycletech.info/fuelmiscl.htm
9D



>>>Refer to author's articles #1A, #1B, & #75 for more information.

>>>An article that describes Lead Substitutes, in depth:
http://bmwmotorcycletech.info/valves.htm

1. An extensive article on Dell'Orto's, covering all their carburetors: http://bmwmotorcycletech.info/dell.htm. It explains in great detail not just how the Dell'Orto works, but is applicable in general to all carburetors ....& MIGHT be worthwhile for you to peruse, even if you don't have one of these carburetors, which was used only on the R90S Airheads.

2A. If you have a high compression ratio Airhead, & you use high octane fuel, be advised that when fueling up at a service station, it is considerably better to NOT fuel-up at the type of 'pump' that has only ONE nozzle/hose. Your fuel may be diluted by a modest quantity of lower octane fuel remaining from the last user...from the internal valve, pump, etc....through the hose, etc....somewhat depending on the type of equipment in use. The dispensing companies don't offer this information easily, & 1/4 gallon or more is VERY common.

2B. There is an old controversy about possible increases in combustion chamber temperatures, etc., when using premium gasoline's in lower compression BMW Airhead engines, where higher octane is supposedly not needed. Gasoline burns at about the same rate under normal conditions, that is, not detonating. The output (BTU) per gallon of Premium gasoline is potentially ....or even likely...to be a small amount LOWER than for Regular. THE ENERGY CONTENT OF FUEL ALSO VARIES WITH THE SEASONAL CHANGES OF THE FUEL. I think it is likely that SOME premium gasoline's WILL give LOWER gas mileage than a regular gasoline will.....assuming the engine ran properly on Regular grade gasoline. Winter grade of road gasoline's tend to have rather volatile things like butane or propane in them to make it easier for engines to start when quite cold. So-called oxygenates, such as alcohol, are often added to most fuels. These additions GENERALLY cause 4%-10% POORER gas mileage. They are not good for your engine, carburetors, hoses, etc. All the oxygenates tend to cause the engine to run leaner with stock jetting in use. Some Airheads, typically later models, are already running on the lean side of best power mixture...& more leaning will cause stumbling, etc.

3. There are a number of types of aftermarket fuel filters on the market, metal ones, cleanable element ones, various sizes, colors, etc. I prefer the impregnated paper type, NAPA #7-02323. That number may have to be entered at the store or on-line as 702323. There is a much more complete article on the author's website on the fuel filters, petcocks, etc: http://bmwmotorcycletech.info/fuelfltrs&petcocks.htm. Due to the age of our Airheads, I am a firm believer in using aftermarket paper filters BELOW the petcocks, mounted vertically, & maintaining clean petcock mesh screens. Tank debris is a prime cause for a gasoline soaked foot (besides old worn float needles or bad floats). Particles of various things manages to get through the tank petcock mesh screens....which are designed to trap bigger particles, particularly the early screens. I clean the petcocks thoroughly every year, by removal (at simple tank cleaning time), blowing them out with compressed air. If the petcock handles are getting stiff ...usually that means at the every several years point ...I do a more thorough tank job....and I disassemble the petcocks & service them. Almost never do I need any parts, other than a very faint smear of silicone grease. Failure to do regular tank cleaning is likely to eventually result in a rotted tank bottom AND a lot of filth getting into your carburetors, or at least fuel screen(s).

Fuel hose, in depth, is covered at 11, well below.  

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