Propane Convert

Propane Convert

“She’s Ugly, But She Sure Can Cook!”

Ed Remitz

IN THE EASTERN shadow of Mount Tamalpais, about 15 miles north of San Francisco, Dick Gotelli has already ridden over 1500 trouble-free miles on his unique propane-eating motorcycle.

The propane conversion was easy for Dick, who owns an engine repair shop in San Rafael, Calif., where he also performs propane conversions for cars, trucks and industrial engines.

Dick, a member of a Marin county off-road motorcyclists’ club, became intrigued with the propane bike project as a way of dispelling that oft-heard notion that all motorcyclists are environmental bludgeons. “Besides,” Dick added, “1 wanted to show that propane conversions are cheap and simple, too.”

At a cost of $125, Dick purchased the conversion parts: a regulator system 'and carburetor for Clinton and Wisconsin industrial propane engines, respectively, and the necessary tubing. He then added a used 1 Ms-gal. propane tank to his 1963, 305cc Honda. Dick explained, “I can get about 50 miles on a tank...the most expensive single item for conversions. A 5-gal. tank, for example, could cost over $30.” Tanks have to be specially designed and constructed, then state inspected. Propane, you see, is bottled under pressure as a liquid, but with low pressure or high temperature, it quickly becomes a high-pressure gas.

The mechanical ingredients were all bolted and hose-clamped into place with little prodding. Dick said probably any propane conversion depot can offer the parts and advice for doing a bike conversion, though it’s primarily an ad lib venture.

The most complex function is served by the regulator system. The first stage reduces the propane’s pressure from 180 psi (in-tank) to 30; the second stage cuts it to 3 lb. and the third drops it to 6 oz., where “the engine then sucks it in through the carb.”

The only engine modifications required were switching to spark plugs two ranges colder, then changing their gap from 0.019 in. to 0.035 in. “because propane is a colder fuel than gas.... It doesn’t have all those polluting additives that help foul plugs, either.” Dick feels the conversions are probably only feasible for four-cycle engines, however.

Dick spent a total of 60 hours converting the bike, “and that included all the scrounging for parts. Any novice mechanic could do the work. It’s very easy and the benefits will pay for the conversion quickly.”

The benefits Dick cited were: a 10 percent power increase; no carbon deposits (he reckoned this would allow the engine to last three times longer); no oil changing (with no carbon only the oil filter has to be cleaned); indefinite muffler life (because “propane produces no acids like gas and it burns much cooler. The engine even runs quieter.”); and no spark plug fouling. Extrapolating from propane car performance, Dick figures the plugs should last over 40,000 miles.

Of course, propane’s most known and popular virtues lie in its cleanliness. Dick explained, “Propane exhaust runs about 54 percent less nitrous oxides, 65-80 percent less hydrocarbons and 85 percent less carbon monoxide than gas.”

Dick’s future propane plans are to convert another of his bikes and take a tongue-in-cheek speed run at motorcycling’s speed valhalla, the Bonneville Salt Flats. “After all,” Dick mused, “any speed we get will be a record ’cause we’ll be the only propane bike there.” RH