B28-28 28X76X18mm Automotive Bearings Non-standard Ball Bearings

Product Overview

The B28-28 is a single-row deep groove ball bearing with a 28 mm bore × 76 mm outside diameter × 18 mm width, specified as a special ball bearing for Honda motorcycle crankshaft and drivetrain applications. It is catalogued under the NSK designation B28-28 J1 CG16 UR and the RICH designation B28-28 J1CG16, and it carries the Honda OEM references 91001-KPF-901, 91001-MJP-G51, and 91001-MGE-003 depending on the model year and application. The bearing is produced from GCr15 chrome steel and is supplied open (no integral seals) for lubrication by the engine or transmission oil circuit.

Critical application clarification: Honda motorcycle crankshaft / drivetrain bearing, not a generic automotive bearing

The supplier form lists the application as “Automotive spare parts.” The OEM and aftermarket data point to a more specific and materially different primary use:

• Honda motorcycle crankshaft bearing: Multiple independent sources identify the B28-28 as a crankshaft bearing for Honda CBX250 Twister (2001–2008), XR250 Tornado (2001–2008), and CRF1000 models. The NSK listing explicitly describes it as designed for motorcycle engine crankshafts (cigüeñales de motores de moto), and Honda parts catalogues list the 28 × 76 × 18 special ball bearing under crankshaft and transmission diagrams for these models.

• Honda drivetrain / transmission applications: The RICH catalogue entry also describes the bearing as a component for Honda drivetrain applications and Honda transmission systems, indicating that the same 28 × 76 × 18 envelope is used in motorcycle transmission positions as well as the crankshaft.

The Application field should be corrected from a generic “Automotive spare parts” to “Honda motorcycle crankshaft / transmission bearing” , with the Honda OEM cross-references added to the old-model or description field. Publishing the bearing as a generic automotive part without this fitment information risks misdirected buyer traffic and fitment disputes.

Dimensional and weight clarification

The supplier form states 28 × 76 × 18 mm and leaves the weight blank. Catalogue data provides the following refinements:

• Outside diameter: The 76 mm figure is consistently supported by the Honda OEM description (“BEARING, SPECIAL BALL, 28X76X18”) and by the RICH and NSK catalogue listings. One Italian NSK distributor lists 28 × 67 × 18 mm for the same part number, but this 67 mm figure is contradicted by the Honda OEM specification and the majority of catalogue entries, and is likely a data-entry error or a listing for a different variant. The 76 mm value should be retained as the primary specification.

• Weight: The RICH catalogue lists 0.413 kg for the B28-28 J1CG16, while the Italian NSK distributor lists 0.5 kg. The difference likely reflects brand-to-brand variation in cage design or internal geometry, or a measurement convention. The listing should use ≈ 0.41–0.5 kg as a reference range, or specify the weight of the actual supplied brand if known.

Load ratings and speed limits: not published

No accessible public catalogue publishes Cr, C0r, grease speed, or oil speed for the B28-28 in its Honda motorcycle designation. The available sources provide dimensions, weight, cage type, internal clearance (Cn), and OEM references, but not standard ISO load ratings. These fields should remain blank or be marked “Consult supplier” rather than estimated from a generic 28 × 76 × 18 mm deep groove ball bearing, because the motorcycle-specific internal design and crankshaft service environment make a generic estimate unreliable. This is consistent with the pattern across the preceding vehicle-specific listings: OEM bearings are specified by fitment and assembly position, not by published catalogue load ratings.

Key Specifications

Note on missing load and speed data: The catalogue entries that list the B28-28 dimensions and OEM references do not publish Cr, C0r, or speed ratings. These fields should remain “Consult supplier” rather than estimated. The HS Code 8482102000 is consistent with a single-row deep groove ball bearing.

Performance Features

• Honda crankshaft-specific envelope: The 28 mm bore × 76 mm OD × 18 mm width is sized to the crankshaft main bearing position on Honda CBX250, XR250, and CRF1000 engines, where a standard metric bearing would not provide the correct shoulder dimensions or oil-feed geometry.

• Deep groove geometry for combined loads: The single-row deep groove raceways carry radial loads from the crankshaft and accommodate moderate axial loads in both directions, matching the load spectrum of a motorcycle crankshaft under combustion and inertia forces.

• GCr15 chrome steel construction: Rings and balls are through-hardened for rolling-contact fatigue resistance under the high-cycle loading of engine service.

• Open configuration for oil-circuit lubrication: No integral seals; the bearing is lubricated by the engine oil circuit, consistent with the wet-sump lubrication strategy of Honda motorcycle engines.

• OEM interchange identification: The 91001-KPF-901 / 91001-MJP-G51 / 91001-MGE-003 cross-references allow buyers to confirm fitment against Honda parts catalogues for the CBX250 Twister, XR250 Tornado, and CRF1000 models.

Application

The B28-28 is used as a crankshaft bearing and transmission bearing in Honda motorcycles, including CBX250 Twister (2001–2008), XR250 Tornado (2001–2008), and CRF1000 models. In crankshaft service, the bearing supports the crankshaft main journal under the radial and axial loads generated by combustion and inertia forces. In transmission service, it supports a gear shaft within the gearbox. The bearing is lubricated by the engine oil circuit and is installed by press fit onto the crankshaft or shaft; replacement requires engine or transmission disassembly and should follow Honda’s service procedure for bearing installation and shaft end-play adjustment.

Ordering & Logistics

• Stock: 87 pcs

• Minimum order: 1 pc

• FOB price: US$10 – US$50 per piece

• Payment: PayPal / Western Union / T/T (100% in advance)

• Delivery: 3–4 workdays after payment

• Shipping: DHL / FedEx / UPS / TNT

• Ports: Shanghai / Guangzhou

• Packing: Standard export packing

• Brand: As required (authorized brands only)

• Country of origin: China

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