Layshaft bearing

It may have been Loctited in by a PO due to a wear if you haven`t been in there before yorself. You may need to heat up the case with a hot air gun (always recomwnded) and pull the bearings.

Good luck, Al.

Slacken gearbox top and bottom bolts, if not already loose. 

As above, just hope it has not been secured using high temp bearing or shaft fit. Most break down at around 230C, but need 2 or 3 cycles to degrade it.

If the primary has been removed just take the box out and get some serious heat in the shell on a bench. Heat the shell with the primary facing end uppermost, heats the bearing recesses quicker and saves gas. 

I can see the clutch push rod in the main shaft, I presume that you have removed the clutch first along with rear chain sprocket etc.

Regards

Dick

Should have gone to spec-savers, I've just reread the mail and it is the layshaft you are trying to get out.

Dick

Al, you have had some good advice above, but no one has said what might help you understand what could be going on.

The layshaft bearing is normally a ball race that does not come apart. The outer is a heat shrink fit in the alloy case that MUST be heated to 200 deg C or thereabouts to get it out or back in again. A powerful hot air gun is ideal if the gearbox is in the frame. It is much easier to have the gearbox out, on the bench, and give it a thump down onto wooden blocks when hot. But, a hot shell should release the bearing easily.

The layshaft is a light press fit into the bearing inner race. It might just come out in your hands, yours does not.

It will all be more difficult if the parts were worn and a previous owner has reassembled with loctite. As said above, you need more heat to break down that loctite. It will have to be on the bench. It is much better to use a gas torch to heat the aluminium shell on the outside. If there is loctite present it will give off white smoky fumes when it breaks down. An IR temperature gun is a big help to know how hot you are getting it.

You need to replace the ball bearing on the end of the layshaft with the roller bearing or the ball with a resin cage, the brass/steel cage on the ball bearing fails, the balls all fall to one side and the rings then move enough so the balls drop out. A sudden lock up happens when one of the balls gets between a pair of gears. 

The layshaft is normally a close fit in the bearing , I use a mole grip on the end of the shaft and give it a tap ,a primitive slide hammer!. If you get the bearing out its usually replaced with a roller bearing which then needs some shimming at the kickstart side to control the end float. Or you could use an uprated ball race as recommended by Mick Hemmings a box specialist. You are right in that the back of the clutch needs a clearance to the sleeve gear, not easy to check, I strip the spider out and torque it up to check with a feeler gauge on my 99 and Atlas. Different to commando but the end result is the same.