Join Date: Sep 2004
Location: 44° 05' N 71° 09' W
It's access to an oil galley (passageway). The drain plug is down lower and is removed with a regular six point socket or wrench.
I've seen plugs like this on other engines before. Some were just oil galleys and others included a check valve to keep some pressure in the lubrication system after engine shutdown.
'06 KLX 250S (more fun than people should be allowed to have)
'72 SL-350 K2 (bump start only)
'72 CL-350 (on injured reserve list at this time)
“I guess it's better to bend a valve in Missoula than to lose your mind in Bozeman.”