Just looked up my invoice for the TDR crank rebuild.
I paid £187 for the crank rebuild. This included new main bearings(x4) and bigend bearings.
I also had the conrods replaced at £12.77 each (x2).
Both cylinders were rebored and new pistons and rings fitted. Cost £23.50 for each rebore and £41.13 for each piston set.
 
I did all the strip down and rebuild work my self.
I needed new a new gasket set which includes 2 base gaskets (£6.34) and a head gasket (£10.47).
I also replaced every bearing and seal in the engine/gearbox too and had the engine cases bead blasted and then I sprayed them. Next purchase should be a set of complete stainless steel exhausts.
You may not need to go to these lengths though.
Total cost for all the parts was quite high as I replaced a lot of things.
I reckon about £500 - £550.
 
No special tools are really required except for a flywheel puller.
There are a few nuts that require a little knowledge to remove without the needed tools but they weren't any real trouble.
The drive sproket nut can be very tight and difficult to remove. I got the local garage to get it off with the air compressor.
The crank (right side) drive gear nut is also tight and this can be removed while the engine is still in the frame as it's easier to hold.
The clutch basket nut is the other hard one. This was again removed with the air compressor as I didn't have a socket large enough the fit it. It is also difficult to get into and you don't want to slip and trash the brittle aluminium clutch basket.
 
Once the engine is removed then it's simply a case of splitting it by removing the 17 bolts in order.
I highly suggest giving the entire engine a really good cleaning with Gunk grease remover and then a good spray down with either a hose or jet wash BEFORE you start.
 
If you do decide to split the engine then You'd be a fool not to replace the 2 crank oil seals at the very least.
I paid £6.04 for the left one and £11.86 for the right.
 
There are 2 small rubber O-rings that keep the water channels sealed between the 2 engine halves, these should be replaced too (£1.20).

Engine bearings and seals.        

Bearing 93306 205760 £20.34
Oil Seal 93105 35426 £4.77
O-Ring 93210 22298 £1.22
Bearing (x2) 93311 42045 £8.86
Bearing 93306 20585 £18.94
1st Gear bearing 93310 22057 £4.94
Oil pump seal 93102 10002 £1.18
Water pump seal 93103 10168 £11.71
Kick start oil seal 93102 20108 £4.91
Gear shift oil seal 93102 12321 £3.11
Gear shift bush 90383 12022 £1.30
Crank seal LH 93103 25108 £6.04
Crank seal RH 93103 35149 £11.86
Head gasket 1KT 11181 £10.47
Base gasket(x2) 1KT 11351 £6.34
Clutch cover gasket 1KT 15461 01 £6.49
Case water O-ring(x2) 93210 15566 £1.20