Fix for Kowa Six lens delayed leaf shutter

Hi

I got a Kowa Six lens that has the issue that the shutter won't open until after a delay. I mean after pressing the shutter button it takes some seconds before the lens fires the shutter. This is not in the V setting, but M and X.

Does anybody know what is causing this? I'll be opening the lena to clean it, so just wondered what to look for.

My other Kowa Six lenses works just fine.

Thanks in advance

This issue is quite common on the Seiko shutters used in the Kowa and Mamiya lenses. Solution is removal and cleaning/lubrication of the shutter cocking ring gear. At that time, the sector gear, main lever and main spring should be removed and cleaned/lubricated.

Thanks! What kind of lubrication should be used?