Without wanting to turn this into a gearbox rebuild thread I'll keep this post as short as I can and then we will get back to twinky specific stuff, I promise!
Firstly thanks to all of you guys for your advice - gearbox and diff have come up a treat. Cross pin diff is a cool bit of kit!
I've changed the input shaft bearing and race. Thanks to some previous posts on this forum i got the idea to run a mig weld bead on the inside of the bearing race to shrink it to allow it to fall out. I was skeptical, but it worked a treat and doesn't look like it's caused any damage to the flywheel cover, except for one little pit. Either way, the new bearing race went in as it should.
new race installed (the circlip wasn't installed correctly in this photo but has since been seated properly)
Trying to fit up the flywheel cover to the gearbox so I can check idler end float has proven difficult. I can't for the life of me get the bearing to seat properly in the race. I've checked that the bearing still fit in the race before pressing it onto the input shaft, and i've also checked with a spare race that the bearing still fits, so it must be an alignment issue - one that is so damn close. Anyone seen this before and or got any of those old school tricks up their sleeve?
I highly doubt that it's warped the flywheel cover when I welded the old bearing race. I think the next step might be to remove the studs from the casing and see if the bearing fits in the race or if the race is no longer circular. if it fits maybe it just needs a chamfer filled into the race.... This new bearing seems to not have the chamfers on both the race and bearing rollers that the old one had. A naff issue that is frustrating me either way
Next photo you guys will see will hopefully be a picture of the box, block and head all together!! Woohoo!