Don't overtighten your drain plug

[Protozoa]

This is common on used bikes I buy. The oil drain plug was over tightened by the PO. After the 6-point socket rounded the hex drive I went to vice grips. Next I tried a hammer and chisel, this usually works but you can see in the pic I stopped once it looked like I was going past the sealing surface. Last resort was a Blue-Point stud extractor - victory. Just a word of advice, it doesn't need to be that tight. On the new one I used a drain seal you can get from any GM car dealer, the one that is steel with silicone rubber. It is the correct size for 11mm ID drain washers and can be reused many times because the silicone doesn't crush. This is on my son's 2002 YZ250.

[Dingateer]

They had it that tight without stripping the threads on the case? I'm impressed

[jets]

Same problem I had on my YZ when I ended up heating the bolt up and knocking it with a screwdriver and hammer. I think it is a pretty common thing on YZ's in general.

[rasta]

i think the biggest issue with that is people not replacing the crush ring or copper washers. bound to strip at some point.

[kouack]

The previous owner was probably thinking that bolt was holding the bike together ?.

I would just add, all bolts and nuts should/shall be tight @ a specific torque, this is why engineer design stuff and select that bolt with that pitch thread/size vs the other one and store sell torque wrenches to prevent surprise/ catastrophic failure on components.

I work in aviation industry and even small screws holding panels we use torque wrench (screwdriver with torque wrench) , not the white knuckle plus 1/4 turn.

[Protozoa]

Amazingly, the threads in the case were not damaged. Heating it up would have been a good option, too. The previous bike was a 2001 YZ125 and the plug bung extends down from the case. On that one the PO overtightened it and cracked the bung. I repaired it with JB weld and put plastic wrap around the drain plug threads and threaded it in until it dried. Afterward I backed it out, removed the plastic wrap, put a new drain washer on and it was leak free.