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Go back to the basics. Octane is based on tempreture and pressure. Larger volume equals more heat which requires higher octane for a given pressure. Smaller bores can run higher combustion pressure than larger ones.

Do not take your ignition timing for granted, mark the flywheel and make sure it is no more than 17 degrees at high rpm. Over the years cdi boxes had different timing curves. Do not use the cdi box marked 3728 or 3729. The 3738 box will give best response safest full throttle use.

Both types have been extensively developed and applied. Do some research and use what works best for you.

Each cylinder pulses opposite each other. If you tied them together the result is zero pulse.

Make sure the cable doesnt hit its internal limit, it will break. Get the nozzle plate first.

If the nose was a little more pointed you could use it to harpoon whales.

How did we race for so many years without girdled heads? Im sure someone will tell you exactly what you want to hear.

We have three original 1993 650SJs with small housings. New ADA couplers fit perfectly.

High compression mostly affects response and spool up. Low pump loading allows acceptable response with lower compression. Your 9-15 with an 85mm nozzle will spool up fairly well with a low exhaust port and 150psi. Going to 185 will make it more responsive to throttle inputs. If you were over...

Make sure the top plastic elbow on the bilge hose has a pinhole vent. If it doesnt or if clogged water will siphon back into the hull.

More compression will make spool up faster since it increases power mostly at low rpm. It wont make it go any faster, that comes from the pipe and porting. I once installed a stock head/gasket on a high port 701, it cranked 120 psi. It took a full second to get on the pipe from idle although it...

Are you sure you need to? They ran 48mph all day with stock inlet/outlets.

They are high rpm pipes that make a lot of power. Power and speed will be great but good response will be a challenge. A low pitched impeller will be required. From there more compression and better fuel will help a lot.

It is for doing "freestyle" competitively. It will be difficult to get good response from such a short pipe on a small engine. A lot of compression and race fuel will be needed with fixed timing. A programmable ignition gets you similar response on pump gas, it takes both to get a small engine...

I wonder how many, after reading this, will get a new battery and not add sealant at every joint. Can the cells be purchased economically? If so then build your own.

Maybe a little more dry running next time.

Carbon weighs less but is expensive. Glass is cheap but heavy. Kevlar makes a good tow rope.

You can put larger pilots in first but be very careful with smaller mains. I-body carbs do not pull as hard on the main circuit as SBNs do so they need larger jets. Reverse jetting is just a phenomena that occures with stock and modded 44-46 SBNs set up for throttle blipping freestylers. It is...

A restrictive F/A (like an OP Vortex) may be necessary for a single 44 on a reed 550.

It is a little easier to get the gas to flow between the crank wheels than over them. The old Ultra 1200 is set up this way. The very best place for reeds is on the other side of the engine but that arrangement doest fit standups very well.