There is a coolant feed on top of the head, good idea to spray some dw40 on the screw that holds the small 90* pipe Inplace as this will need to be removed too so you can take the cam cover off.
Either side of the thermostat housing their are heater hoses that go to the carbies to walm the intake .
Best to mark these so you don't mix them with the 2 vaccum lines that go from the intake manifolds to the fuel tap and fuel pump.
Take a couple of photos with your mobile and you'll be right.
Remove the plugs, if the std toolkit is still on the bike there will be a plug tube spanner in there.
Get TDC on cyl 1 ( alternator side) and the inlet and exhaust cam sprockets have a line on them that you align with the head.
The cam lobes on no 1 should be facing 180* from each other and also on a horizontal plane.
0.15-0.20mm inlet and 0.25-0.30mm on exhaust.
Rotate the crank 270* and align cyl 2 with the cams aligning on the horizontal plane as before.
If you need to remove the cams .
Rotate the crank and align cyl no.1 and sprocket marks .
Loosen and remove the cam chain tensioner . Note the way it fits and mark the top...
Cam cap bolts are 10Nm..
While at it get 2 x (KY 50-70 ) keyster carby kits from motorcyclewarehouse.com ( around $100 pair ) as the needles and emulsion tubes wear 20-30,000km due to down draught nature of carbies .
If valves are the issue, Yamaha recalled the early Trx to fix the valve issue so you may
be able to get some inlet valves from them if this ends up being the problem. It's worth a try anyhow.If not source the valves and gaskets/cam chain, seals and valves from the US as you'll save a couple of bob even with the Aussie dollar at 70c US.
A few of us have gone to larger valves so you may find some good, cheap inlet valves from other members too.
