You said:
yes, exactly. I have this engine in a carbon fiber -6 superfreak badass jet ski hull. The jet ski also has dual mikuni 46 mm carburetors with a power factor laydown pipe, MSD enhancer ignition with a lightened 61x flywheel, and a 150 mm setback torrent pump. do you know what those items are.
ChatGPT said:
Updated saved memory
Ohhh man—you’re not just riding, you’re straight-up launching a missile. That setup is next-level. Here’s the breakdown of all that gear for sure:
️ Your Build – Absolute Freestyle Weapon
Hull: -6 Carbon Superfreak
- That’s a super light and nimble hull—shortened 6 inches for insane rotation speed and responsiveness.
- Perfect for tricks like flatwater flips, barrel rolls, sub-ups, and coffin slides.
- Being carbon fiber, it's strong and light, so that 900cc torque monster throws it around like a toy.
Engine: XScream 10 mil stroker 900cc
- Crazy torque. Built for back-to-back tricks and fast recovery.
- Balanced internals, ported, possibly with domes in the 185+ psi range?
Carbs: Dual Mikuni 46mm
- Huge airflow for freestyle. Those suckers are tuned for punchy throttle response.
- Likely with T-handle screws for quick tuning and return springs for safety.
Exhaust: Power Factor Laydown Pipe
- One of the most aggressive freestyle pipes out there.
- Designed for max torque and bottom-end grunt—super important for loading up the pump and launching tricks.
- Laydown position helps keep center of gravity low and clears room in the engine bay.
Ignition: MSD Enhancer + Lightened 61X Flywheel
- MSD Enhancer gives you adjustable rev limit, timing advance, and better throttle snap.
- Lightened 61X flywheel lets that engine rev lightning fast—less rotating mass = faster throttle response, quicker spins.
Pump: 150mm Setback Torrent
- More thrust and hook-up than stock Yamaha pumps.
- Setback design increases intake volume, lets the pump “grab” more water on takeoff.
- Awesome for staying hooked up in the surf and getting consistent lift on flips.
In short:
This isn’t just a setup—it’s a precision freestyle machine built to flip, spin, sub, and fly. Sounds like you’re deep into the scene—are you riding in surf or flatwater mostly?
4o
You said:
I'm riding exclusively flat water. Can you help me with jetting recommendations?
ChatGPT said:
Updated saved memory
Absolutely—I can help dial in your jetting to match your flatwater freestyle setup. You're working with a torquey 900cc stroker, dual Mikuni 46s, Power Factor laydown pipe, MSD Enhancer, and that lean, light hull… so you need crisp throttle response, strong midrange, and just enough top end to hold the arc in a flip—not peak speed.
Baseline Jetting Recommendations (Mikuni SBN 46mm, dual)
Main Jet:
- 140 to 145 range
- Since you're running a big pipe and a big stroker, you need enough fuel at full throttle—but not too fat to bog the flip arc.
- Start at 145 and tune down if plugs look wet or you notice blubbering.
Pilot Jet:
- 67.5 to 75
- Critical for your low-end throttle punch—start at 75 for a richer baseline (especially if you're running a high-compression head).
Needle & Seat:
- 2.3 is a good balance for freestyle.
- Consider 2.5 if you're having fuel starvation in extended sessions or after hard landings.
- Run dual 115g springs to reduce bounce and flooding on impacts.
High-Speed Screw:
- Start at ¾ turn out
- Fine-tune by plug chops or feel—should transition clean at full throttle with no bog or surge.
Low-Speed Screw:
- 1¼ to 1½ turns out
- Adjust for throttle snap off idle—listen for clean, crisp rev.
Pro Tips:
- MSD Enhancer timing will affect your jetting—richer jetting if you're running aggressive advance curves.
- Use BR8ES or BR9ES plugs depending on how hard you ride (8 = hotter, 9 = cooler).
- Keep an eye on plug color—tan = perfect, white = lean, black = rich.
- Run high-octane premix (at least 110 or a 50/50 mix with 91+), especially with a stroker and high comp.
If you tell me your elevation, fuel type, and compression numbers, I can fine-tune this even tighter for you. Want to get into tuning for throttle response or plug chops next?
4o
