What would it take to convert a Honda CT90 to propane?

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sgtlethargic
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What would it take to convert a Honda CT90 to propane?

Post by sgtlethargic »

Is there a mixer small enough for a 90 cc engine? They're air-cooled, so what about a regulator (Is that what they're called?)? Ignition timing?

Thanks

C3H8
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Re: What would it take to convert a Honda CT90 to propane?

Post by C3H8 »

There are mixers for very small engines. You don't say what this is used for but the Honda CT is only 7HP so I presume it is a generator or similar application. You don't say where you are but in the USA there are at least 2 or 3 companies that probably have a venturii style mixer for that engine. The engine would operate off vapour so tank size would be fairly important but in reality it would probably operate off a 20LB BBQ tank without any issues.

Frank
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Re: What would it take to convert a Honda CT90 to propane?

Post by Frank »

I think sgtlethargic has CT90 motorcycle and I have my doubts that a 20lb cylinder would be the ideal tank in this application. A 5# or 10# DOT might be a better option.
https://en.wikipedia.org/wiki/Honda_CT90

I've seen some examples on the internet (can't recall where right now) where people have converted their bikes to propane and the tanks were much smaller - more like a 14.1 oz cylinder. Just checking now, I see that there are specific LPG tanks for motorcycles but these appear to be found elsewhere than North America.

C3H8
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Re: What would it take to convert a Honda CT90 to propane?

Post by C3H8 »

Thanks Frank. I thought he was just referring to a model of Honda engine. As you stated a 20# would not be the proper tank for a motorcycle. I don't know if they still have them but countries in Europe used to make tanks for motorcycles that were half LPG half petrol. The outside of the tank was made to look just like the regular motor cycle gas tank. I forgot to answer the other question asked. Timing in these engines is usually the same whether they are running on Petrol or LPG. The engines do not have normal ignition items like a distributor. They usually have a magneto built into the flywheel so making any changes is complicated. Because of this a small power loss should be expected on LPG.

C3H8
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Re: What would it take to convert a Honda CT90 to propane?

Post by C3H8 »

Regulator would be something like a Beam model T60. This regulator would require vapour as a fuel supply. It can do liquid but obviously not on an air cooled engine. To do liquid there are other options like the Century G85 which can be heated by mounting it near an exhaust pipe. Vapour withdrawal is the better choice though for an engine that small.

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