Here is an oil strainer from a kwakka , I guess gasket goo is cheaper than gaskets , but look at all the junk in there
I had to use some, I could see daylight between the cases - been bent, probably landed on the gear lever shaft. At least there was a strainer on kiffsta's kwakka.
Have a look at the case sealant's, they're good for uneven surface's and are oil/fuel/coolant resistant Hondabond, Yamabond Threebond 1184, semi drying sealant https://www.ebay.com.au/itm/Three-B...h=item2cbde6191c:g:l7oAAOSw~BhbGuGE:rk:1:pf:0 Threebond 1104, drying fuel resistant https://www.ebay.com.au/itm/1x-Thre...h=item3f8f51d94b:g:L64AAOSweZJaN4I~:rk:7:pf:0 Permatex Motoseal https://www.ebay.com.au/itm/Permate...h=item2387b58bf4:g:TYsAAOSw3h1ZUOE7:rk:1:pf:0
I think I used the permatex for the clutch cover (it was what I had), and the ThreeBond 1215 when assembling the crankcase (no gasket, sealant only).
Been helping a friend with an XL250R that he bought cheap from a nearby village. Could not believe the amount of red silicone used to replace gasket of sidecover. And this is why you don't use the 'more is better' rule. This should have an O ring to seal the oil gallery, not red crap, and look inside the hole to see the piece just sitting there waiting to drop off and block up the oil feed tube (about .5mm dia) on the left. More here in the barrel oil feed hole.
It works well. But always use sparingly. It is also not a substitute for an O ring. I striped a very noisy engine some time ago and found a lump of metal stuck in an oil pressure relief valve. The valve could not close so the engine ran with bugger all oil pressure. No idea how it got there. I suspect from a poor repair previously.