But the tank is leaking alright, right along the mounting flange. Is this a common problem? What is the best way to fix it? What is the cheaper way?
Been there, done that. Tried JB Weld, and it stopped the leak. However, when I tightened the tank bolt on that flange, the weld popped and she leaked again.
I put the tank back on while the tank repair was drying.
My bike did the same thing. The guy I purchased it from tried fixing it with silicone...
so I pulled the tank and noticed it was leaking from the left mount where it was spot welded to the tank. Here are the steps I used and knock on wood, so far so good.
1. Empty tank and fill with water.
2. Spread mount away from tank in the area where it is cracked.
3. Sandblast the area. (you will need to remove the petcock and make sure no sand is in the tank later)
4. Empty the water rinsing a few times to get any sand out, mount the petcock and let the tank dry.
5. Use tank sealer putty to fill the crack and make sure to push it through so it forms a lip on the inside (at this point the mount is still "stretched" away from the tank).
6. Smooth out the putty on the outside of the tank using just your finger.
7. While the putty is still wet temporarily place it on the bike and bend the mount almost to final fit leaving just about 1/4" gap so it will allow pressure to be put on the joint instead of possibly needing to open the distance and chance breaking the seal that was just put.
8. Prime using black primer, sand.
9. Paint with color that matches your bike. Let dry. (20 minutes or so)
10. Mount the tank back onto the bike.
11. Fill with petro.
12. Take it for a spin!
The bond should be strong enough that it won't break if you need to take the tank off again but I cannot be positive as I have not had to take the tank off since. I wish I had taken pictures of this but I was in a rush fixing the bike 4 hours before I had to leave for work and I wanted to take my bike...
Let me know how it goes.