Add my name to the list of those who have had layshaft bearing failures this year. Mine happened while leaving the parking lot at work on Tuesday afternoon. I consider myself blessed that it didn't happen that morning on my way to work, a crowded 17 mile, 70+ mph urban interstate commute. Got the familiar bump on the back of the leg from the K/S, looked down & saw the K/S at 6 O'clock, so I pulled over immediately, shut it down, & pushed it back to the motorcycle parking lot to retrieve later with my truck.
Disassembled my gearbox in situ to find a disintegrated Portuguese FAG 6203, balls & pieces of brass cage strewn about the bearing cavity & the sump. Looks like I lucked out (again) because there was no other damage to gears or shafts, the layshaft bearing outer race was still snug in the case, and no sign of a crack in the case radiating out from the layshaft bearing counterbore.
There was some damage in the layshaft bearing counterbore. Evidently when the cage let go a couple of the balls exited the race towards the bottom of the counterbore (towards the clutch) and were wedged outward between the case & the bearing outer race. This actually pushed the race about 1/3 out of it's bore, and the balls rolling around in that gap mashed some of the case into the bearing land area. I was able to modify a 2" sanding disk to fit in the counterbore, mount it in a long-nosed die grinder, and sand down the mashed aluminum to restore the land.
My question is how deep should the layshaft bearing counterbore be in the case? I presume it should be equal to the width of the layshaft bearing, but a sanity check depth measurement would be very helpful. Anyone have an undamaged gearbox apart that could take a quick measurement for me?
Thanks for your time,
Disassembled my gearbox in situ to find a disintegrated Portuguese FAG 6203, balls & pieces of brass cage strewn about the bearing cavity & the sump. Looks like I lucked out (again) because there was no other damage to gears or shafts, the layshaft bearing outer race was still snug in the case, and no sign of a crack in the case radiating out from the layshaft bearing counterbore.
There was some damage in the layshaft bearing counterbore. Evidently when the cage let go a couple of the balls exited the race towards the bottom of the counterbore (towards the clutch) and were wedged outward between the case & the bearing outer race. This actually pushed the race about 1/3 out of it's bore, and the balls rolling around in that gap mashed some of the case into the bearing land area. I was able to modify a 2" sanding disk to fit in the counterbore, mount it in a long-nosed die grinder, and sand down the mashed aluminum to restore the land.
My question is how deep should the layshaft bearing counterbore be in the case? I presume it should be equal to the width of the layshaft bearing, but a sanity check depth measurement would be very helpful. Anyone have an undamaged gearbox apart that could take a quick measurement for me?
Thanks for your time,