oil leak coming from where tachometer cable enters piston cover

[NoDah]

Anyone know what could be causing this?

 

[pidaster]

It's been a while since I've had it out but I think there's one or two O-rings in there. They might just need replacing.

 

[maliciouscycles]

There is a Seal They are pretty cheap and easy to change , They harden and crack over time.
http://www.partsfish.com/oemparts/a/hon/506f6dedf8700229747b7a8e/cylinder-head-cover
#10 $2.73

 

[motogtp]

There is a trick to getting the seal out. You drive a small diameter screw through the seal. As you keep screwing it in the tip will bottom on the seal land and the threads will back out the seal.