Layshaft bearing again

[quote="Brendan S they show someone TIG welding around the circumference of a crankcase bearing race[/quote]

The TIG heat transfers to the alloy, which expands at a greater rate than the steel.

I have done 4 gearboxes and all bearings fell out when the cases were heated.

Brendan S said:

I have not been in the gearbox so don't know if this would even apply here, but in the April Classic Bike they show someone TIG welding around the circumference of a crankcase bearing race to cause it to shrink, and allowing it to be lightly drifted out. I'm not understanding the logic of that as I would have thought the race would expand.
Brendan

Click to expand...

Everything in the weld zone shrinks after cooling. Weld distorsion. Weld several lines on a steering head bearing race and after it cools the race will be several thousandths smaller and fall out. Its easy on a large race with easy access but a small layshaft brng in a blind hole inside at the bottom of case is different. You want a nut that your slide puller will screw into and weld it to the top of the old bearing race.