This is my R & B I built some years ago and failed to get to run. After completing another project a couple of years later, I made a determined effort to get it to fire up. The valve timing, ignition and compression were all OK so it must be the carb. that's the problem. The engine is fueled with propane. To cut a long story short it turned out to be the the carbs. air inlet was far to large. So a suitable restricter made and fitted. Priming the KN demand valve and with a few swings of the starting handle, the engine popped into life.
The engine though still needs some tinkering but it runs.
(Running this type of engine on pneumatic tyres probably not a good idea, a bit bouncey)
John