GS090 CEN PINION GEAR 21T

CEN GS090 PINION GEAR 21T

The CEN Racing GS090 Pinion Gear is the 21-tooth transmission pinion gear used in compatible CEN 2-speed driveline systems. Historical CEN parts documentation and multiple current specialist listings identify GS090 as the 21T pinion, while GS092 is the dogbone/drive shaft part number.

VERIFIED PRODUCT DATA

• Manufacturer: CEN Racing
• Part Number: GS090
• Component Type: Transmission Pinion Gear
• Tooth Count: 21T
• Transmission Role: 2-speed pinion gear in compatible CEN driveline assemblies

PART-NUMBER CLARIFICATION

Some current reseller/catalog pages incorrectly label GS090 as a dogbone, but original CEN manuals and current specialist parts listings consistently identify GS090 as the 21T pinion gear. The corresponding dogbone is GS092. GASHEAD RC uses the technically documented CEN part-number assignment here to avoid a fitment error.

2-SPEED GEARING ROLE

In the CEN 2-speed transmission system, GS090 works as the 21T pinion and pairs within the same gearbox family as the GS089 17T pinion and GS087/GS088 steel spur gears. Tooth count directly affects transmission ratio and gear engagement, so GS090 should not be substituted with another pinion tooth count unless the complete gear pairing and transmission setup are known to be compatible.

GEAR MESH & SHIMMING

CEN service documentation emphasizes correct gear alignment and spacing in these 2-speed assemblies. Improper mesh can chip or damage spur gears and increase noise, friction and bearing load.

• Verify the mating spur gear is the correct part and tooth count.
• Check shims/spacers are installed in the correct positions.
• Confirm the gear rotates freely with no tight spots through a full revolution.
• Do not run a fresh pinion against a badly damaged spur gear.
• Inspect clutch-bell bearings and shaft play before finalizing mesh.

WEAR PATTERN DIAGNOSIS

• Tooth-tip polishing or chipping: may indicate excessive backlash or insufficient engagement.
• Heavy whine: can indicate overly tight mesh.
• Rhythmic clicking: can indicate a chipped tooth, eccentric rotation or damaged mating gear.
• Uneven wear across the face: can point to shaft misalignment or bearing play.

INSTALLATION CHECKLIST

• Confirm the application calls for CEN GS090 / 21T.
• Inspect GS087/GS088 or the applicable mating spur for damage before reuse.
• Check clutch-bell or supporting bearings for play.
• Install the correct shims and spacers for the gearbox configuration.
• Set mesh so the gear train rotates freely without excessive backlash.
• Rotate by hand before starting the engine or motor.
• Reinspect gear contact after the first operating session.

WHAT CEN DOES NOT PUBLISH

The available CEN documentation identifies GS090 as a 21T pinion gear, but does not provide a complete current specification set for pitch/module, outside diameter, face width, bore diameter or pressure angle. GASHEAD RC does not invent those dimensions. Match the part by the exact GS090 designation and compatible transmission documentation.

GASHEAD RC NOTE

This listing was corrected from an erroneous Dogbone description. For this part number, the technically supported identity is GS090 = 21T Pinion Gear. If you need the corresponding dogbone, reference GS092 instead.