Wiseco 2 Stroke Bearing, Upper Rod TOP END BEARING - 14 X 18 X 16.2mm (H-WB139)

The Wiseco B1012 is a replacement top end bearing for two-stroke engines. It sits in the small end of the connecting rod, carrying the piston pin, and is listed as a fit for the KTM 85 SX / 85 SX Big Wheel and Husqvarna TC 85 / TC 85 Big Wheel.

Top end bearings are a wear item, so this is aimed at riders, parents and workshops doing a routine two-stroke top end rebuild — typically alongside a new piston, rings and circlips. It is supplied as a single bearing in the 14 x 18 x 16.2mm size.

Please confirm the bearing dimensions and your exact year model against your engine before ordering.

• Wiseco replacement top end (small end) connecting rod bearing
• Needle roller bearing for two-stroke engines
• 14 x 18 x 16.2mm size
• Listed fitment for KTM 85 SX / 85 SX BW and Husqvarna TC 85 / TC 85 BW
• Wiseco part number B1012
• Sold individually as a single bearing
• Suits routine top end rebuilds alongside a new piston, rings and circlips

• 1 x Wiseco B1012 top end connecting rod bearing

Check the bearing size and your model year against your engine before fitting — top end bearings are not interchangeable between sizes.
Leave the bearing in its packaging until you are ready to install it, and handle it with clean hands or gloves; grit and dirt are the main killers of a new bearing.
Pre-oil the bearing with two-stroke oil or assembly lube before it goes into the small end.
Inspect the connecting rod small end and the piston pin for scoring, discolouration or play at the same time; if either is marked, the bearing alone will not fix the problem.
Fit new circlips with the piston — do not reuse old ones, and make sure they are fully seated in their grooves with the gap positioned as per the engine manufacturer's instructions.
Use a proper piston pin tool where required and support the piston during fitting; never hammer the pin through the rod.
Replace the top end bearing every time the piston and rings are changed, following the engine manufacturer's service interval.
Never reuse a top end bearing after a seizure, piston failure or any ingestion of debris.
Allow the engine to warm up and heat cycle before hard running after a rebuild, and use the correct premix ratio or oil pump setting.
Store spares in a dry place in the original packaging to prevent surface corrosion.