Yesterday I went to change the oil on my Honda CB250 (2001 model). This is the second oil change I've done after an initial one when buying it at 15,000km. Now last time we changed the oil it went from red (motul oil pours out red) to almost black pretty quickly - within a week. Google searching suggested two things a) It's fine - Carbon turns stuff black quickly and this is normal, particularly with no oil filter in the CB250 b) It's not fine - this is an indication of an oil screen that's never been taken out and cleaned. Not having a stake in the internet debate, I decided that this time I'd take out the oil screen to clean it to be safe. But on opening the RHS crankcase I found the oil pump had two extra pieces when comparing it to photo in the manual I have for a 1988 CB250. Also, giving one of the screws on the oil pump a turn (need to take it out to get at the screen) they wouldn't budge (screen had also obviously never been taken out), so I put the oil screen in the too-hard basket and didn't bother touching oil pump/screen etc. Figured I could live with oil getting dirty quickly, rather than risk something going wrong with the oil pump down the line and facing a hefty repair bill. Also, opening the crankcase discovered two things: 1) It was very hard to pull off, required some light taps with a rubber mallet, but quite sure I was as gentle as could be. 2) The plastic/rubber sealant around the crankcase cover was cracked and chipping - some came off with the crankcase cover, some was left on the casing still on the bike etc. So basically, without changing anything, put the RHS crankcase back on. Poured in the new oil, found it was seeping slowly but surely out of the bottom of the crankcase/crankcase cover (where some of the sealant had cracked off, no surprises.) So drained the oil into a storage container, then left it overnight for the rest to seep out. Today bought some silicone gasket sealant to fill the gap where the previous sealant had cracked off. Put a small amount of silicon sealant on, which is now poking below where the leak used to be. Opened up the crankcase and cleaned out the remaining pockets of oil so the sealant would adhere properly. Now, I'm leaving the sealant for 24 hours, but tomorrow putting the oil back in and checking for leaks. Is there anything else I need to check for? My brain also tells me that the silicone (small amount may feasibly be poking up at the bottom of the crankcase if it's sealed properly) and oil will not affect each other, and it's built to withstand high temperatures, but are there any risks with this stuff I should look out for?