AMC gearbox

Previously Neil Wyatt wrote:

Anyone know if the layshaft bearing can be replaced without removing the gearbox from the frame. I suppose it can be done but does it make any sense to remove the box?

I want to replace with the later superblend.

Sometimes the drive side layshaft bearing comes out with the layshaft. It just isn't that tight a fit in the case. I had to Locktite mine in. If the layshaft slides out of the bearing first then I have a tool that will pull the bearing out. The tool is intended for pulling hydraulic lifters out of V8s.

I haven't heard of a superblend for the gearbox but there is a roller bearing. Mick Hemmings doesn't like that conversion so I didn't do it. I don't think the layshaft can flex badly enough to benefit from a superblend. What would you do about the plain bush on the other side though?

I changed mine without taking the gearbox out. I also used a ball bearing and so far it has lasted about 25 years and 50,000 miles. The original bearing failed after only 170,000 miles. Might have to change it again in 60 years or so...

I found bearing removal in the frame wasn't a problem (I used a heat gun and a slide puller to remove the layshaft bearing), BUT: To get the new ones in square and true I ended up removing the (by then) empty case to get it in the oven, as the heat gun was nowhere near man enough to heat the case to allow the new ones to 'drop in' (RGM Superblend fitted)

As an adjunct to the above... Bike was a Mk3 Commando (at 21k miles), and I really didn't want to remove the centre stand, rear wheel et al as alluded to by many manuals. However, once the empty shell was left, removal was possible without taking ANY of the above off.. I even managed itwith the rear brake pedal still connected! But there was no way either new bearing could be drifted in withoutTHOROUGH heating......