Here are the existing threads on the subject:
http://bannedcr500riders.com/board/viewtopic.php?t=341
http://bannedcr500riders.com/board/viewtopic.php?t=636
http://bannedcr500riders.com/board/viewtopic.php?t=2081
http://bannedcr500riders.com/board/viewtopic.php?t=2202
http://bannedcr500riders.com/board/viewtopic.php?t=4117
http://bannedcr500riders.com/board/viewtopic.php?t=4840
http://bannedcr500riders.com/board/viewtopic.php?t=6241
http://bannedcr500riders.com/board/viewtopic.php?t=6337
Many thanks to all the original posters.
Please post your thoughts, experiences, comments and suggestions!
General comments gleaned from the boards:
- wash tank with simple green solution to clear out residual fuel
use modeling clay and pack it all around areas that touch, be sure there is at least a half inch of clay that protrudes all around, carefully put the tank in position and press down so you create a negative impression into the clay. This will tell you where you need to push in the tank for a clean fit
mark the tank with notes on how you need to modify (depth/area/etc...)
pre-heat the tank with boiling water
use a good head gun and set it to low
keep heat gun 8-12 inches from tank surface
if the tank starts turning brown that means it is burning
heat an area at least 2x the size of the area you need to mod
Once the area is hot and pliable (it might turn a little shiny), you need to work somewhat quickly to get the job done.
use a non-heat conducting, smooth/rounded object to manipulate the tank
The plastic will become slightly more brittle with heat cycles, and as you move the plastic, the wall thickness will become less uniform. This is why you use an object that is larger than the area you need to move and you heat a much larger area as well, to spread out the stretching to keep the tank as stress-free as possible. If you push in the tank with the round end of the barrel of the bat, you keep the stress point to a minimum. If you need to move an area that is smaller, try using the end of a hammer handle...that works too.
go slow and take your time!
- From beginning to end, the process took me 3+ hours (note to self: stock plenty of refreshments)
set up a really stable jig to hold the tank. This is a must as it will make your life much easier. Mine worked, but was ghetto and a PITA at times when trying to really press on the tank
the end of a ball bat was too unwieldy to use (due to length and trying to hold the heat gun with the other hand) one of those mini souvenir bats would probably work really well
i had trouble at times with hot plastic sticking to the hammer handle or other wood objects i used. to resolve the issue i removed the heat source momentarily, allowing the plastic to cool slightly and then gently scraped it apart using a screwdriver, end of a hose clamp, whatever was handy
i had my best luck using the rounded side of the head of a hammer to press on the tank, though it did get really hot as I kept it under the head gun while working. using a ball peen end also would probably work really well. I noticed the least amount of plastic sticking with this method
having a second set of hands would have been VERY helpful (see refreshment note earlier)
As I got closer to being done, I test fit the tank on the bike, the hot plastic actually got a small indentation from the plug wire so I know where I needed to keep working
I pulled through the tank in several small areas due to plastic sticking, but was able to scrape/move plastic from other areas and re-melt it in place
I noticed that the inside of the tank was showing cracks due to the inside surface not heating at the same rate or temp as the outside. more reason to try and pre-heat the inside
- definitely going to try pre-heating with boiling water
has anyone tried pre-heating at a low temp in the oven in conjunction with the hot water prep?
I'm thinking adding boiling water and heating in the oven for say 30 min at 200 (while the wife is out of course)
what about using some sort of release agent on the object used to mod the tank to prevent sticking (silicon spray/vegetable oil/water)?
what have you guys done to re-locate the fuel spigot? I chose to leave mine in place and it was a bit of a challenge as the tank needed the most modification right next to the spigot mounting point. However this still puts it at the lowest point on the tank, which I wanted.
Thanks
Shawn