Re: Propane conversion
Here is another idea that may work even better. Use the fuel inlet on carb with the normal needle arrangement for metering, with the propane, and run a hose into the carb venturi to siphon oil from a small tank, controlled by a plumbing valve. Just don't forget to open it when starting and riding!
The carb slide and needle might not stop the flow of gas when closed but could probably come close to it if the idle screw is omitted. The bike would die when the throttle is let off. This is how I run my gas bike anyway, for an extra "kill switch".
Some people are using the fuel jet on the briggs carbs as a fuel feed, removing the bowl etc from the carb. (don't want the needle and float shutting off the carb) (on 5hp lawnmower 4stroke) You have to put engine gasket/sealant in the appropriate holes since there is no bowl and no gasoline.
Perhaps this can be done to the happytimes as well.
Remember these motors are pretty low tech! I would say just supply it with oil and as much as it wants before it starts visibly smoking like something burning in the microwave. Better to err on the side of caution.
Last edited by happycheapskate; 01-01-2011 at 10:24 AM.