Loosen front cam chain tensioner locknut (12mm) and bolt
(10mm) in the centre of pic ten.
Push down on cam chain (pic 11) and re-tighten locknut and
bolt because it takes the pressure off the top cam chain.
Loosen the rear cam chain tensioner locknut (10mm) found at
the rear of the cylinder block (pic 12) and pull the main cam
chain tensioner up to release chain tension and tighten nut up
again.
If this proves difficult use long thick screwdriver to push back
on the cam chain tensioner (pic 13). This takes the tension off
the cam chain.
Remove the right-side end cap (three Philips screws). An
impact may be required (pic 14). Note that top screw has O-ring
(pic 15).
Use 17mm ring spanner to turn crankshaft so that the T-mark
aligns with crankcase joint line at the front (pic 16). Check
that No 1 cylinder (ie furthest left drive side) camshaft lobes,
both inlet and exhaust, point towards spark plug hole (pic 17).