Quick Throttle Body cap question (both missing)

[Commuter]

Quick question, with reference to this diagram below. Part 10 the throttle body cap, both are missing on the bike after checking it over this afternoon( I think someone has been playing without my permission)

Is this a problem? Haven't noticed any problems apart from lower power than normal? Am I causing any damage to anything

 

[Steptoe]

Air is being sucked in - the tickover should have increased without the caps.

Stick some tape over them for now until you can replace them.

 

[ciderman gs]

both of mine went missing through old age ( they perished) 50p each from the stealership mine were anyway they told me they are new parts every service