My son is starting to race with a single cylinder Honda. Parts are relatively inexpensive and you only need half as many as for a twin. Great. He can learn riding, gearing, tuning, such as pipe building, cams, etc with much less work. Good fun for both of us.
A good approach to tuning is to work in stages. First, work on the externals such as carbs, manifolds, timing and spark, and exhaust. And how to ride the thing. You learn a lot about a motor at this stage.
Next, work on breathing, such as a port job and bigger valves. Maybe a cam. Can you make the engine flow and produce adequate power near redline with these modifications, using the standard size, and compression ratio? Many engines can't, and its time to look at other motors. An engine that cannot breathe enough with standard displacement will only be worse with more cubes.
If your engine breathes good at high rpm, its time to look at the next stage, such as increasing displacement or compression, or both. These last options can be expensive.
This method will save you $ and time. I had to give up on several engines because of problems detected in the early stages. The head geometry would not allow them to breathe or they would not hold together at high rpm. I had minimal money invested and this allowed me to move on to better engines.
Good luck with your project. Hope to see it on the salt.
