Another minor update. All stripped back as far as I need to go.
did some significant homework before stripping the primary chain. Reading from a combination of the duplex chain upgrade document (from the technical library), the maintenance manual and a bit of googling (mainly to see what the vacuum pump looks like, since you are removing it blind.
some links to useful threads/info:
(west Yorkshire engines! seems a bit of a douce, but gets you a good look in there and some basic principals)
with the cylinder head off, it makes a couple of things easier than the guide. these are 1, you can freely rotate the crank before starting the stripdown and line up the fuel pump locking hole, with TDC and the double marks on the crank gear with the balancer idler wheel all together. (Rotate the crank round a few times until they all line up)= no need to paint a mark.
I now have the utmost respect for anyone who manages to remove the vacuum pump with the cylinder head attached!! with the head off, you can swing the fule pump right out of the way which lets you in to all the vac pump bolt.
Another tip, a slim tent peg (we all have then knocking around!) is ideal for locking the idler gear.
A slight bit of marking on the chain guides and no obvious signs of wear. the vac pump is out for the duplex upgrade, but i'm still in a dilemma about cheaping it up!!
a few hours cleaning off old liquid gasket and prepping for the rebuild.
One last thing, I took out the thermostat today, and dunked it in boiling water - completely dead. I guess this is the root cause.
A few pics. With any luck i'll start receiving some parts to build it back up later this week!