When valve seats were cut into cast iron cylinder heads you needed the lead, and with that you also had ridges form at the top of your cylinder between the deck and the top ring, which took out the upper ring in a relatively short time. Ammoco came out with "white gas" (unleaded) back in the late 50s and when cars started showing signs of needing a valve job a few tanks of white gas would help the valves pound a new seats and seal the cylinders, a short term "fix" utilized by used car dealers. Engines run on leaded fuel rarely went past 100K miles without major expense. Going to unleaded fuel was one of the best changes made for increasing longevity.
Unleaded fuel was introduced in 1973, IIRC, and had an octane rating that made the pumps ping, not an option, then, for air cooled British motorcycles. Back in '79 leaded fuel was fading fast, I had a T140D at the time and made friends at the local airport, the manager told me that my Triumph was, officially, an "Ultra-light", that it had no wings merely underscored the fact that it was a work-in-progress, people would fly anything. I got desparate and managed to call into Texaco's research facility seek tetra ethel lead. The chemist I spoke with said ixnay, way too dangerous, they didn't like working with it, highly carcinogenic, but did yell me that a little lead went a long way. He advised me to mix one gallon of 110 octane Av-gas with 4 gallons of available auto fuel to get an octane rating in the low 90s, the Triumph was OK with that mix. You can still do that, of course, and come out paying taxes and end up with an octane rating in the mid to upper 90s if you start with a 93 octane feedstock, which is readiy available around here; there is a roumer that Shell 93 has no alcohol in it, I can't say for sure
In the 80s I was virtually motorcycleless, overcome by the KCM syndrome (Kids, Career and Mortgage) also by 1980 leaded fuel was unavailable in Massachusetts I remember that octane numbers were going up, but what did you folks stoke you British iron with for motion?
RS
Unleaded fuel was introduced in 1973, IIRC, and had an octane rating that made the pumps ping, not an option, then, for air cooled British motorcycles. Back in '79 leaded fuel was fading fast, I had a T140D at the time and made friends at the local airport, the manager told me that my Triumph was, officially, an "Ultra-light", that it had no wings merely underscored the fact that it was a work-in-progress, people would fly anything. I got desparate and managed to call into Texaco's research facility seek tetra ethel lead. The chemist I spoke with said ixnay, way too dangerous, they didn't like working with it, highly carcinogenic, but did yell me that a little lead went a long way. He advised me to mix one gallon of 110 octane Av-gas with 4 gallons of available auto fuel to get an octane rating in the low 90s, the Triumph was OK with that mix. You can still do that, of course, and come out paying taxes and end up with an octane rating in the mid to upper 90s if you start with a 93 octane feedstock, which is readiy available around here; there is a roumer that Shell 93 has no alcohol in it, I can't say for sure
In the 80s I was virtually motorcycleless, overcome by the KCM syndrome (Kids, Career and Mortgage) also by 1980 leaded fuel was unavailable in Massachusetts I remember that octane numbers were going up, but what did you folks stoke you British iron with for motion?
RS
