I had to deal with stripped drain plug myself
I had to deal with stripped drain plug myself
Finally, a subject I can comment on semi-knowledgeably.
When I bought my '83 GS650 (22K miles) last year, unbeknownst to me it came with a stripped drain plug. It had a slight oil leak when I got it, and when I tried to change the oil the first time, the plug just spun while tightening.
I tried to find an oversized plug, but my drain plug was 14x1.25, which seems to be a very difficult size to find *any* plug for, much less oversized.
So, first I tried some temporary fixes, as I wanted to keep the bike going for a while before I had time to tackel this. I tried high-temp, oil-safe thread sealant, and that did a pretty good job of reducing the leak. If you're looking for a cheap, temporary quick-fix, I'd recommend that. You can get a tube at a hardware store for less than $5.
I considered the helicoil option, but instead of drilling a bigger hole and then inserting threads, it made more sense to me to drill a bigger hole and then CUT new threads. I dropped the muffler, then pulled the oil pan. Got a 16x1.25 thread tap, and cut new threads. I then got a Fumoto valve (
http://www.fumotousa.com/ ), which basically replaces your oil PLUG with an oil VALVE. This means that you never have to take out your oil plug again. You just turn the valve, and the oil comes out. (I also have one for my truck, and they don't leak as you might think.) This means virtually no possibility of stripping the threads in the future! = ) The only disadvantage that I've found so far is that the oil comes out slower.
The hard part for me was finding a thread tap of the right size. I ended up buying a whole metric tap set to the tune of $200, but it's already paid for itself as I've used it for other things on the bike. Some auto parts stores will loan tools like tap sets, so if you're looking to go cheap, you could call around. It's harder to find a metric tap that big, though.
If you don't want to go with the oil drain valve, the local auto parts store had 16x1.25 drain plugs, as that's a more common size.
While you have the oil pain off, I'd suggest checking the oil screen to make sure nothing's gunked up on that. Also, on my '83 oil pan, there are 3 bolts that are longer than the rest, which took some head scratching initially to figure out. I'd also recommend replacing the oil pan gasket. When I did this the gasket was $15, and a whole kit (70 or so gaskets) was $80. I ordered a whole kit and I'm glad I did. I've used all but 4 of them now, and buying them seperately would have been much more expensive.
Once I had the tap set, this was a pretty easy job. (Though, I broke off 4 of the exhaust bolts in getting exhaust system off, which lead into a much more difficult job. If you do get the exhaust bolts off, make sure you put anti-sieze on them before putting them back in.)
Hopefully this helps somewhat. Good luck!