RM85 pinhole water leak on head - Advise please

[Ragbert]

My BIL son has a RM85 that they are fixing up as Father and son project. Upon the test drive this week end I noticed a pinhole water leak on the left side of the head. Can this be repaired or should they look at a replacement head?
Eenig iemand met ondervinding in so tipe herstel werk op 'n silinderkop?

Edit: hier is die foto's.

 

[BuRP]

 

[Chrisl]

 

[katana]

 

[Ragbert]

 

[Ragbert]

 

[JohnB]

 

[Vilaishima]

 

[BuRP]

 

[Ragbert]

 

[Ragbert]

 

[katana]

 

[Ragbert]

 

[Vilaishima]

 

[Smittie2]