How to change oil?

[cybrid3]

Hey guys,

Looking for some info on how to change the oil on my bike as I cant seem to work it out. There is no fill port. Its a Jap Import to UK RMX 250. The frame is 1995 but I know its had its engine changed.

Here are some pics of the engine. I am trying to work out what year its from also

The engine number is

J1134 - 104006

Just wanna change the oil but am completely baffled

 

[2001Rm125]

other side

 

[whenfoxforks-ruled]

Good question! I have to ask, it does have a drain bolt?

 

[cybrid3]

It had a small sump bolt underneath. The filler cap was behind the cover. Strange. Never seen that before. Most caps are exposed