Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

A further update on this engine for the interest of other current or potential owners.

One thing I discovered is the vavle rocker's leg ( where it sits the push rod ) can be adjusted from the inside using a plier. That's a big plus and helps with tuning greatly.  As others have mentioned you want to set the rockers with minimal play. So the valves are opened immediately and widely. Exhaust valves need to open more than intake to create a strong scavenging effect. This is due to the nature of 2 in 1 and primitive carb used on this engine and more important to fix the spitting fuel out of carb intake!

Once you adjusted and tested the outcome ( when engine is warm ) you can add some super glue to the base of the rocker to keep it in place.

I can't insist enough on ensuring you have a reliable ground for the CDI. I used a wire from the ground point to under one of the foam legs. Now there is no misfiring or internal spark to kill the hall sensor.

I enjoy running this engine now, satisfying low idle rpm but fast pickup on open throttle. I am using a small desk fan to keep it cool.

Another tip is if you already added oil to the crankcase and using oil mixed fuel, soon or late you will have oil leak, mostly due to the fact that no gaskets are used in these engines. But it's easy enough to add it yourself. One way to get rid of excess oil is to undo the lower screw on the front case ( after warming up the engine and shutting it down), put a tissue under and tilt it 60 degrees over a soft rag. The excess oil will come out from the screw hole. Much easier and cleaner than letting it leak from the cylinders.