All things being equal

[Czakky]

Ok, all things being equal when making fun, useful power on an air cooled RD what proves the most beneficial?
Exhaust tuning: chamber, etc
Carburation: round slides vs flat slides, manifolds, boost bottles, reeds
Port timing:
Compression ration: reshaped head/combustion chamber, milled/decked cylinders etc
Ignition: better spark, ignition curve

Let's say AFR is spot on with good quality street gas.

Better yet give a percentage to each!

[Czakky]

Here's my undereducated guess.

Exhaust: 35%
Carbs: 15%
Porting: 25%
Compression: 12.5%
Ignition: 12.5%

I guess I vaguely understand that port timing and exhaust tuning work together and that a properly shaped combustion chamber will influence ignition allowances.

[gwcrim]

A good, powerful engine is a well engineered system.  Can't go big somewhere and get too much unless everything else is in harmony.  Port timing is probably the biggest determinant, then exhaust chambers, then compression, carb and finally ignition.  That's how I'd rank them.  But still, they all need to be suited for each other.

[pdxjim]

I'm no authority, but for a stock aircooled RD, I'd say ditching the points ignition and skim/squish the head would be the place to start.

[m in sc]

I'm no authority, but for a stock aircooled RD, I'd say ditching the points ignition and skim/squish the head would be the place to start.

Yup. and cleaning up the ports. but a good tune is key for baseline. stock bikes tuned well are very fun to ride. this is why i've never modded my R5, except for the ignition. Its a damn hoot to ride.

[Czakky]

Good to hear some input from some experts.

[sav0r (CL MotoTech)]

Exhaust is dollar per horsepower the single easiest and cheapest improvement.

There are however many gains beyond that. Electronic ignition certainly makes things a lot more simple.

[RDFL]

The very best thing to do is if you need to lose weight lose it, better for acceleration, braking distance, fuel mileage and your health.