I do believe I have principles and as part and parcel of those principles, I do care for the environment too, but as a design professional I also tend to approach resolving challenges in my general life in logical ways.
Ways that I can tackle within my abilities, budget, facilities and also just general technical understanding in a worldly sense, if you know what I mean.
I read your first piece and the first thing that came into my head was 'BOOM'. What did I just read? Is there something that I don't know about or is this a crazy brainstorm idea after a long session at the pub....or maybe you are a scientist/chemist or something, and you are talking about propane conversions as just a completely known and straight forward thing that's common in your country/region.
My logic then kicked in and I thought to myself, why would someone who was that sensitive about petrol emissions buy a bike with the biggest petrol engine in production anywhere in the world? My brain was struggling to comprehend how to read this thread.......So that's why I said I was interested to understand more.
I don't mean any disrespect to you, it's just that you've kinda blow my mind somewhat.
One fundamental question I have is: Who is going to give validity to such a conversion for use on the highway and who would give insurance? I for one wouldn't feel very safe riding a bike around with a pressurized gas canister on board. Maybe it can be made safer in the structural shell of a automobile but bolted on the top of a bicycle?
Hi Jagster,
Think I didn't reply to your last paragraph. In my province, Québec, the SAAQ, the French accronym for the drivers' and licence plating bureau (licence plates are more expensive here as they include minimum car insurance) are governed by law that includes a process for semi-, and fully custom vehicles. Whether it's a home built trailer, bike customization or a Frankenstein car (complete rebuild from recycled parts). There's a process. But only for one-of's = special approval, where you pay a government engineer for a full review of work, a certified mechanic app'd by gov for detailed inspection of all parts aswell as road testing. This, likely similar in other places.
Not all mods or work will be covered by all insurance companies and some may be expensive or not insurable.
This is in sharp contrast for type certification for series production of a bew vehicle, not the subject here.
Having said all that, goverments in Europe, the US and Canada, likely many other countries, have accepted compressed hydrogen to a level of 700 bars of pressure in fuel tanks stored under family cars, as discussed in another post. Hydrogen is one of the fuels with the highest flame propagation speeds and very explosive, yet very low energy density at atmospheric pressure. Gasoline/petrol if explodes is a liquid that will wet your skin while burning. A gas like butane, propane and methane will not wet your skin and won't spill at your feet staying to burn. Both carbon fiber and kevlar are stronger than steel.
Contrary to a gasoline/petrol tank a propane tank does not need an air vent to drain and feed engine. So in the fire triangle: air/fuel/ignition a propane tank has just fuel, a gasoline/petrol tank has air, so the propane tank is less explosive.
Now, you know you're riding a Rocket with a 2.3 or 2.5L engine just a few inches below your family joules and no chassis? Like me.

Just saying. Hopefully my verbal diarrhea has reassured you not put you off.
Thanks for these checks and balances
CrazyX
(xian)