remove the exhaust , with the exhaust off look up the exhaust port with a small torch to check the valves, manually move your kips rod by hand to see if all three valves are moving freely , the two outer valves will be in similar position if timing is correct [ when you pull the kips rod fully the centre valve should raise and the two outer valve should expose the exhaust sub ports
if you have problem with valves the engine cylinder will have to be removed ,
you may be able to retime the clutch side valve by removing the kips rod bush