Removing gas tank - 1981 gs100g

[Noreg]

It (clymer repair manual) says to disconnect the "fuel line", is this the line I can see from the petcock closest to me that goes to the carbs? Will removing it leak a lot of fuel out of the carbs?

Is it really just one bolt, two wires, and one fuel line to disconnect?

Am I correct in understanding the petcock is attached to the tank, and putting it in "PRI" will result in all the fuel pouring out of the nipple the fuel line previously were connected to?

Could I just buy a length of same diameter fuel line at the local car store and attach that to drain the tank?

I believe the fuel is old (last owner barely used the bike), and I want it drained. The real reason I want it off is to gauge if I can check the valve clearance myself (or if it appears to tricky) and to place the wire for the GPS somewhere sensible.

Any idea how to dispose of old gas?

[tom203]

Yes to all!
get some fuel line, connect to petcock nipple, put in “PR” spot, and let old fuel flow into a container. Dispose of old gas in annoying neighbor’s vehicle clandestinely.
consider adding a bit of fresh gas and sloshing it around to remove more tank debris.
Get a new petcock or suffer later!

[cowboyup3371]

Buying any fuel line at your local auto parts store will not give you good results because of the size differences (metric versus standard). Do the best thing and buy new fuel line from your local motorcycle dealer; you'll get more hose than you'll need immediately for the price.

[Redman]

It (clymer repair manual) says to disconnect the "fuel line", is this the line I can see from the petcock closest to me that goes to the carbs? Will removing it leak a lot of fuel out of the carbs?

. ......

.
Yes, that line. CAn pry it back with big screw driver blade, while also pulling on the line.

No, will not leak fuel IF petcock is in ON or REServe position.

.....
Is it really just one bolt, two wires, and one fuel line to disconnect?......

And one vacuum line. THat is the smaller one that is more to the inside. It goes to the intake in front of #2 carb.

Is easier to work on the vacuum line and the gas line if take out the bolt (on 82 and after are two bolts) and lift up on back side of tank and prop up a couple inches with something. Gives you a better look and gives more room for fingers and hands and tools.

........

Am I correct in understanding the petcock is attached to the tank, and putting it in "PRI" will result in all the fuel pouring out of the nipple the fuel line previously were connected to? ......

YES. PRIme position will allow fuel flow without there being any vacuum.





Other thing about removing the tank:
- when remove the bolt, also gather up the rubber spacers, and set them aside, else will fall and get lost.
- When lifting the tank back and then up and away, there will also be a drain line from the fuel sender come with the tank.
- After lift off the tank (and set it somewhere without it knocking the petcock to the PRIme position), go back to the bike. See those round rubber cushions on the tank mounting points near the steering neck..... take off those round rubber cushions and set them somewhere, else they will fall off sometime and roll away to where you cant find them.

[Noreg]

How long does a petcock last? Mine was replaced sometime between 2012 and today. I realize they probably doens't last 39 years, but do they generally last 10? Or am I due a replacement?

This all makes more sense, thank you all for the help. I will do the fuel tank removal shortly.

Is there no fuel in the fuel line? And none that can come out of the carberautors?

Ill take care not to lose any parts, and Ill flush the tank out with some fresh fuel. I was thinking of putting it in a bucket to see if there is any rust or other non-fuel things in the fuel.

[Noreg]

I removed the tank, the wires were a pain to take apart and the fuel hose was not coming lose from the petcock. The vacum line was easy though. I did get the fuel hose lose from the fuel filter.

I drained like 9 litres, and there is a tiny amount of fuel left in the tank. Sadly now both my fuel cans will be full, so Im not sure how to get rid of it without buying a third fuel can.

The washer that is by the bolt magically dissapeared when I took the tank off, luckily it magically reappeared as I was draining the tank.

8.6mm is not the right internal diameter for the fuel hose, Im guessing 6mm but I had some trouble finding that at the store. If I could find it I could just cut the old one off and replace it (seems somewhat brittle on the inside). Should probably get a new fuel filter too (the housing might have been empty).

I spilled suprisingly little fuel (mostly because it takes a long time to empty the tank and I was holding the tank).

I am concerned that the bottom of the tank seems somewhat rusted (presumably this is from water sitting in the bottom?), so I wonder if I need to like, remove it somehow.

But I will fill it up with fresh fuel so that it wont rust more or collect condensation and then Ill try changing oil and filter.