I bet you could get a small piece of copper that has some NPT on the end. It should screw right into it. You could bend it to fit against the frame and dump down under the bike. Just be careful not to hit it in the woods and rip it off. I know there are plenty of small copper 90* bends that would work too. Just make sure you get the bend to point down. You could drill a hole right under the spot where it dumps that would allow you to keep it safe from hitting stuff on the trail. I usually just pull my motor off to drain the oil. I know, it's a pain, but it doesn't take a lot to pop it off and stick it back on. I only change my oil in the spring since I only get to ride it during the warm months. I run synthetic in mine, and I've never had problems with it. Pulling the motor to change the oil also provides a good excuse to buy something new and fun to stick inside (like a cam, new valves, etc.). My wife doesn't see it like I do, but not many do.