Trx 250r leak

[Luise602]

So I have a 87 250r and I notice its leaking from the bolt where you usually drain the tranny oil bought a new bolt and crush washer btw the bolt it's not the original the one I bought Any ideas?

[evaneyeball]

I'm assuming it is still leaking after the new bolt and washer. Then I would check to make sure that the case isnt cracked because the bung that the bolt goes in that broke off on mine and was causing a slow leak then when I took it out it caused a whole deal of rebuilding and welding the case back up

[The norm]

So I had a similar issue with my sons R. I replaced the crush washer a couple times and it still leaked. I eventually ended up buying a M14X1.5 oil plug and tapped the hole to fit the plug.  New crush was and the M14X1.5 plug solved the problem.
Before I tapped the hole to M14X1.5 I noticed that the hole had hardly any threads. I got out my dial calipers and measured the bolt. It was .500"(1/2")! Then I checked the thread pitch. It was 1/2-20(fine thread). Then I compared a M12x1.5 and the 1/2-20 drain plug. They had nearly identical thread pitch. The problem is a M12x1.5 plug is .47244" and 1/2-20 is .500". When a previous owner of the R decided to run a 1/2-20 tap over M12x1.5 they didn't think about how little thread engagement there would be. It almost looked like a thread cut on top of a thread.
I then stood the R up on the grab bar, coated a tap with grease and cut new threads. The M14X1.5 drain plug I bought had the same hex size as a oem M12x1.5 plug and the same size flange.
I no longer have an oil leak messing up the floor in my toy hauler!
Loren

[2ndmoto]

Could be a burr or gouge on the case. Copper is only going to yield so much and might not be filling these surface imperfections thus allowing oil to seep by. You can sand out the imperfections. If you do, use something very flat (file, flat plate, glass..etc) try to stay perpendicular to the hole (roll and pitch) as much as possible