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A tiny exhaust leak will make it bogg. Cracking the hood will troubleshoot that.

Low ports will limit power but they are the most responsive. I have found the throttle response gets slow unless you want to set compression and ignition timing for high octane fuel.

Try cracking the hood and make sure the tank is venting.

Use bearings with a C3 or C4 and make sure they aren't too tight in the housing. If they are overheating then they fit too tight.

Dry rev it until the thermosensor starts shutting it down. That will push out all the water. Corrosion is the real problem so use cheap tcw3 oil. The engine will last longer with the cheap stuff.

An upswept nozzle will make a superjet porpoise. They may be beneficial on a flip ski although it could make boarding a short ski more difficult.

You need to be careful with timing advance until the main jets/top screws are set rich of peak power. After that it’s safe to use a little more initially and adjust the ignitions retard curve. Nobody can appreciate how easy pistons are to burn until they do it themselves. Kawasaki’s tend to need...

I have a 93 that still has 03/92 hand written inside.

The FX1 was designed in 1991, when 550s with 440 pumps were winning the world finals. These pumps needed to turn over 8000rpm to work. Yamaha mismatched the engine and tried to compensate with a tall prop. That doesn’t work very well on standups. There’s not enough inlet pressure so they...

I would save the pipe for something with a 144 pump. Definitely find a stainless impeller, none will load a piped 701 at low speeds. The FX1 has a 440 pump.

On small engines, I can tune SBN44s a little cleaner at 1/4 throttle and still have response when compared to SBN46. Both are nearly identical and work well for standups. I can’t understand why people throw rocks at I-body carbs yet love their aftermarket hatchet jobs. Many of them are just that.

You should be able to get the squish tight enough with the metal 760 gasket. I like to custom cut 64u heads. According to the books, the squish is a little wide with OEM fiber gaskets but I’ve never burned a piston. ADA heads are ever popular, I would use one if they used a 760 metal gasket...

I would talk about carburetors, if it made as much an improvement. Do you know your port heights? How far will your pipe rev before it goes rich? What RPM are you turning? The last question is answered by the impeller. It’s the one item that is relatively easy to change. Yet nobody wants to do...

I would talk about carburetors and loud mufflers like everyone else, if it actually made an improvement. Do you know your port heights? How far will your pipe rev before it goes rich? What RPM are you turning? The last question is answered by the impeller. It’s the one item that is relatively...

There are not many impellers flat enough for high ports and pump gas. Most riders will never know the difference that an additional 200 RPM can make in power response. If they did there would be a LOT more discussion on this subject.

The low port cylinder is much easier to make work. It will be more responsive but a little slower at top speed. The exhaust port should be widened, especially if you have a pair of 44s. High port cylinders will have you always looking for better response. You can get it with a flatter impeller...

Finding a light that works with an msd may be difficult. You will also need to make a mark and a pointer on either the flywheel or coupler. most people just line up the stator marks and not worry about the actual timing.

A strong after fire generally requires an overly lean carb setting. It most commonly happens when you rev a cold engine. I still use composite water boxes and have blown one up once. I’m a lot more careful when the engine is cold now.

What is a big boy engine? Remember larger bores will always have higher fuel requirements. Standups can get away with really hot setups where the same engine would melt in a couch.

All he has to say is his engine and carburetors are bigger, even if it’s not. Maybe give it a name that excites his intended customers.