92160-3756 Motor Mount for Kawasaki JS 550 SX 550 JS 440 JS 400

Crankshaft Main Bearing for Sea-Doo

This crankshaft main bearing is a replacement engine component built to support the crankshaft in Sea-Doo 1630 ACE and 300 series setups, and it cross-references OEM part 21-300.

Overview

This crankshaft main bearing is made to carry the rotating load of the crank inside the engine case, keeping the shaft aligned and running true. It is the bearing type selected for Sea-Doo 1630 powerplants found in 300 horsepower watercraft. Riders and mechanics rebuilding a 21-300 engine will find this crankshaft main bearing suited to the job.

Built For Performance

• Cross-references OEM part number 21-300
• Built to carry radial and axial loads from the crankshaft
• Hardened bearing surfaces for wear resistance in high RPM marine engines
• Precision tolerances for correct oil clearance and smooth rotation
• Designed around the 1630 ACE three-cylinder platform

Fits These Machines

• for Sea-Doo 1630 ACE models
• for Sea-Doo 300 series watercraft
• for Sea-Doo models using the 1630 engine with part 21-300

On-The-Job Use

• Crankcase rebuilds after bottom end bearing failure
• Top and bottom end refresh on high-hours 1630 engines
• Marine engine machine shop assembly work
• Preventive replacement during full engine teardown

Specs At A Glance

Good To Know

Q: How many main bearings does a rebuild usually need? A: Main bearings are normally replaced as a full set across the crank, so confirm the count for your specific 1630 engine before ordering. Q: Should bearings be replaced together with crank seals? A: Yes, seals and gaskets in the same area are typically renewed at the same time to avoid repeat labor.

Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.