I bought back and am "restoring" my old 85 XR600R that has been sitting in my friend's garage since I sold it to him in 1993. I have replaced a bunch of parts, including just about everything on the dual carbs but the carb bodies and the slides (bikebandit.com loves my wallet) as well as a bunch of electrical parts. I just got everything back together and it is running great (thanks to some great carb advice from folks in this forum). The plastic and the seat is in excellent condition. The tank was in great shape except the decals were yellowed, brittle and flaking off. I took the bike out for a quick run around the neighborhood last night, amazed at how great it was running. After it cooled down, I started to clean the bike up a bit. I sprayed some citrus cleaner on the tank last night to remove some old greasy spots (DEP Citrus Cleaner from Home Depot). The tank cleaned up great! I went out this morning to look at the bike in the daylight and smelled gas in the garage. I looked at the tank and there was a huge crack (with some other spider cracks) all the way through from the top to bottom of the left front edge of the tank right where I had spent the most effort cleaning off the old grease spots! The crack opens outward, almost like it was pressurized with compressed air until it ruptured. No one had been in the garage and the bike had not fallen over. I have used this cleaner before and it is pretty powerful, but I've never had a reaction with plastic before. I know gas vapors get through plastic tanks and cause decals to bubble up (which is why they perforate the decals now). It's almost as if the older plastic lets more vapor though and that vapor reacted with the residual of the cleaner and somehow cracked the tank. I know this sounds wierd, but I assure you I am not yanking anyone's chain. Has anyone seen anything like this before?