Per Laurenne Mansbridge in response to Richard L.

Thanks for your post.
With regard to the cooling fins, all RCV SP series are cnc machined from solid (rather than diecast like conventional 4-strokes), and this machining process means it is not feasible to change the cooling fins. If we went to a die cast design we would consider changing the fin orientation, however research into this suggests the results would not be significant, as the current configuration potentially increases cooling due to turbulence.

Secondly RCV SP engines don't really have a tendency to overheat any more than other 4-strokes. Instead, because of their streamline shape they can be too tightly cowled without enough air flow over the engine (both air in and air out). As long as basic cowling rules are followed they shouldn't be any overheating problems. Rules include allowing at least 1" air inlet with 3" air outlet. If tightly cowled arrange a scoop within the cowl to direct airflow over the engine.

Best regards
Laurenne