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On a standup, no, other than already having several that are pretty good. Many years ago it was noted that you could get better radar speed with pre-large hubs. They do suffer more in rough or white water.

Large Hubs prevent air from lingering inside the pump. They work better and handle more power. Small hubs aren’t necessarily bad depending on conditions.

That bond line is a terrible design. It’s structurally weak and dangerous for the rider. I’m sure they will sell a million of them.

I have been working on X2s again trying to make a high port 750 work with a Superjet B pipe. It was a little different than I remember from 33 years ago. Here is what I have learned. (1) It takes a very flat impeller!!! (2) You will very likely melt the front piston with a single carb!!! I...

Any exhaust that is heavier than an FP head pipe needs sheet metal gaskets. Even Factory pipes occasionally crush fiber gaskets and come loose.

That 96 sxi was the best original hull 750s. What hurts the low speed thrust its small 76mm nozzles. Kawasaki was trying to make them go as fast as possible for the magazine reviews. A nozzle from a 750sx or ss/xi is 80mm and will provide more thrust. A 650 nozzle is even better except it’s...

It mostly depends on the pipe with high port cylinders. That OEM pipe is long enough to pull more impeller load compared to an aftermarket pipe. If the pipe runs over 7000rpm, I always have to start reducing the load for decent response. Last year I could get new small hub 11-16 concords for...

The FX1 is like Kawasaki 550-650-750 because you have get them on an edge to turn. Pre 08 Superjets have a lot more lateral grip and turn flat by simply moving the bars. They are much easier to ride. I prefer a 92-96 750 for edge to edge turning. To me they feel like a larger FX1 with a much...

The old straight 16s are too much load plus they cavitate and vibrate a lot more than cambered blades. A straight 15 is good on 650s and high port 750s. The 16s need a low port 750 or an SXR cylinder to get enough low end response.

Shaft tapers are the same on all 650-750-800. Early 750 flywheels were countersunk at the mouth of the taper so they fit 650s and early 750s.

Try removing the plug boots and pull on the metal wire in the leads. It’s common for those to break internally and then the insulator and boot stretch over the broken wire.

The big pin 750 cylinders make less low rpm torque than 650s do. Solas finally made their 750 small hub concord impellers very flat but didn't change the pitch numbers in any meaningful way. Their 09-15 and 11-16 work great in 650-750 applications. Measure the distance from the leading edge to...

It would be nice to have better data on the really large engines. I think riders aren't keeping good notes and are also not wanting to talk about failures. Big engines turning 7000rpm are stressed like Mod class 550s, except they vibrate a lot more! All the 68mm stock stroke stuff should be...

On any two stroke there are two main aspects that govern engine life. One is the width of the exhaust port and the other is operating rpm. A race winning cylinder turning 7800rpm will need pistons every dozen hours or so. The same cylinder with a slightly narrower port turning 7200rpm can last...

A stinger set for smaller displacements is a contributing factor. There can’t be very many tuners racing your exact engine combo so you may be on your own. Make the stinger as large as you can without hurting the pipe too much. It’s easy to restrict if you oversize it.

Those are large diameter pistons , you will have to find a way to reduce temps. I suspect lower compression and later ignition timing may be required for sustained WOT.

Are your carbs tuned rich of peak rpm? Are you sure there is no air getting into the fuel line? I always have to add a second pump and air/fuel separator to keep pistons from melting in a race boat.

Prop open the engine cowl and see if anything changes. What’s the top speed? If needed the pump load can be lightened by bending the trailing edges up .100”. I never measured an SC nozzle. All plastic 650 units are over 82mm and metal 750 units are 76 or 80mm. Larger diameters do make more thrust.

This time do a pump swap.

Good luck finding dimensions.