No gotchas in removing the fuel tanks.
Putting the fuel tank back on is another story, especially if you need to leave it off overnight and the temperature is hot. The shape will change just enough to make you go nuts when trying to align the mounting bolts...
Keep close track of the rubber inserts, aluminum sleeves and thin rubber washers associated with both rear mounts -- when you pull the tank back/off the frame, it's common to have some/all of these bits fall out.
Before you pull the tank off, you'll have to disconnect the fuel pump electrical connector and the two quick-disconnects on the fuel lines. Not much finger room around there. With my LT's, I would unbolt the tank, then lift the rear end of the tank up a couple inches and stick a chunk of 2x4 under the center rear of the tank to hold it up while I undid the connectors.
When undoing the fuel line quick disconnects, hold the release tab until the disconnect is completely apart -- prevents the sharp edge of the release tab from cutting the o-ring on the male part. Same on reassembly. A paper towel under the quick disconnects will catch the few tenths of an ounce of fuel that spill out of the connectors. Turn each downward briefly to dump the last couple drops.
On reassembly, a quick hit of silicone to lube the disconnect o-ring makes it slide into the female half easier.
Purchase a few quick disconnect o-rings -- that will ensure that you don't cut one when reassembling
When disconnecting the two drain hoses at the front right of the tank at the connectors about 10-12" below the tank top, remove on hose from the top of one connector, and the other from the bottom of the other connector -- that way you can't mix up which is the gas bib and the tank vent hose (of course, if you've done a canisterectomy, this is no longer a problem!)
When reinstalling the tank, a hit of silicone on each of the forward rubber mounts helps the tank slide on easier.
When reinstalling the tank, it is *really* easy to not see that you've trapped the two drain/vent hoses between the right front edge of the tank and the right tank mount. This will crimp off the tank vent, giving you the same symptoms as a clogged charcoal canister (tank collapse, engine stalling, etc.). How easy? I've lost count how many times I've pull an LT tank, and I know about this problem -- yet I've done it more than once!
Before putting the tupperware back on, turn on the ignition key and place the kill switch into the run position -- you want to hear the fuel pump run for ~2 seconds (the normal line-pressurization cycle) to confirm that it's correctly assembled. I usually place a clean folded paper towel under the fuel lines before turning on the key, and let it sit under the lines for a few seconds after the pump runs to confirm no fuel leakage (i.e., fully seated quick disconnects, with no nicked o-rings).
Take *great* care when starting the tank mounting bolts back into the frame. The weight of the tank and the pressure from the annoyingly-pita seat subframe tend to make it hard to run the bolts in straight -- but if not started cleanly, the steel bolts can absolutely bung-up the threads in the aluminum frame backbone.
It would be nice if a list of items like Mark posted could be included in the maintenance manuals (factory or otherwise!). I've never understood why manuals aren't written to actually help out with doing the maintenance as much as possible. Anyway, I have to say that it is very easy to forget to reconnect a hose or a harness when installing the tank. The last time I did it I forgot the fuel pump at the bottom, and it wouldn't start. Luckily I hadn't put on the fairing yet when I figured that one out. I think I'm going to get into the habit of tying on bright streamers to everything that needs to be reconnected when reassembling. I have a roll of the stuff (can't even remember why). I might as well use it for something practical.
The only item I would add to Mark's excellent post is to ALWAYS use new HNBR *green* O-rings with the quick connects.
At 25 cents each they are cheap insurance vs. using the typical *black* NBR type. Ethanol eats NBR for lunch and tends to desiccate (dry) them rapidly - hence the premature failure.
They're usually easy to find at a good hardware store, sold as air conditioning o-rings and they are indeed metric. They are easy to confuse with an SAE sized o-ring - but a sharp eye can easily tell the difference side by side on top of a white piece of paper.
If the quick connects don't click together with minimal resistance you have the wrong size, and a tiny little bit of silicone grease as Mark recommended is indeed the correct lubricant since it is completely inert.
I typically set the tank over a saw horse attempting to keep it's shape, particulary if it is going to be off for a while. Not sure it makes any differences, it still takes some finagaling with a pry bars to line everything back up.
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