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SKU:
NLT1F00785
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Sea-Doo 159° Rotary Valve 420924502
$22.99
In Stock
$22.99
Sale price
$22.99
Regular price
This new aftermarket 159-degree rotary intake valve replaces Sea-Doo 420924502, 420924209, and 290924502 for compatible 657, 717 / 720, 787 / 800 two-stroke engines.
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Compatible Models
We do our best to list all compatible models. Although this may be the part you need, your exact model may not appear below.
Compatible equipment / model
- Sea-Doo 657 engine applications requiring a 159-degree valve
- Sea-Doo 717 / 720 engine applications requiring 159 degrees
- Sea-Doo 787 / 800 engine applications only where the parts manual specifies this valve
- PWC and sport-boat models must be verified by engine and timing specification
Product Overview
Hard starting, spit-back through the intake, weak low-speed response, or damage discovered during engine service may require rotary-valve inspection. Incorrect timing, worn rotary shaft gears, excessive cover clearance, crankcase leaks, and carburetor faults must also be checked.
The thin valve opens and closes the intake ports according to crankshaft position. Its 159-degree cut and installed timing are engine specifications, not tuning guesses; incorrect setup can prevent the engine from running correctly.
Confirm engine family, required 159-degree valve, original reference, plate thickness and condition, timing marks, rotary-shaft backlash, and cover clearance. Use the model-specific timing procedure.
Key Features & Performance
- Precision 159-degree intake timing cut
- Stainless-style replacement plate as shown
- Fits the compatible Sea-Doo rotary-valve drive system
- Cross-references several earlier service numbers
Replaces Part Numbers
- 420924502
- 420-924-502
- 420924209
- 420-924-209
- 290924502
Common Uses
- Replacing a bent or scored rotary valve
- Correcting intake timing during an engine rebuild
- Servicing the valve after foreign-object damage
Technical Specifications
- Product Type: Two-stroke rotary intake valve
- Timing Angle: 159 degrees
- Engine Families: Compatible Sea-Doo 657 / 717 / 720 / 787 / 800
- Condition: New aftermarket replacement
Installation & Fitment
- Lock the engine at the specified crank position
- Use the correct degree template or timing marks
- Inspect rotary shaft, gear and cover surface
- Measure cover clearance before final assembly
- Turn the engine by hand and verify timing before starting
Compatibility Notice
Northline Parts does its best to list all known compatible models, but the correct part may fit an application that is not shown above. Model year, production date, serial number, engine or equipment specification, installed options, and previous repairs can change fitment. Match the original part, reference number, dimensions, connectors, mounting points, and product photos before purchase.
Frequently Asked Questions
Q: Can I install it without timing it? A: No. Rotary-valve timing is essential to starting and performance.
Q: Does every 800 engine use 159 degrees? A: Do not assume so. Verify the exact engine and service specification.
Q: Can a worn rotary shaft damage the new valve? A: Yes. Inspect backlash, gear condition, cover, and shaft movement.
Q: Is this an original-equipment part? A: No. This is a new aftermarket product. Brand names and part numbers are used only to identify compatible applications.
Part Summary
keywords: Sea-Doo 420924502 rotary valve, 159 degree 717 intake valve, Sea-Doo 720 hard start timing, 787 rotary valve replacement, 420924209 two stroke valve
Brand names, model numbers, and reference part numbers are used for identification and compatibility purposes only. Verify the original component, specifications, and application before purchase.