After 18+ years and 75,000 miles the fuel lines on the 93 K1100RS I recently acquired are rather old and cracked.
Here's the one from the FPR to the gas tank:
And here's the one from the fuel rail to the tank. Not only is it cracked at the bend but it also has some longitudinal cracks along the length of the line:
Since I plan to keep this bike for a little while I decided to replace all of the fuel lines. To save a few $$$ I decided to use generic fuel line to replace them. It takes a little less than four feet of fuel line to replace all three fuel lines. I purchased four feet of fuel line for $5/foot at a local auto parts store. The OEM fuel lines have an inside diameter of 8mm. Fortunately, in the US anyhow, one of the standard sizes for fuel lines is 5/16" - which is 7.9mm. If you're doing this,
be sure to purchase fuel line that is rated for fuel injected fuel systems. "Regular" fuel line is not made to withstand the pressure in a fuel injected system.
You'll also probably want to get a couple of 13mm hose clamps for reconnecting the two lines to the fuel pressure regulator as the factory used one-use Oetiker clamps on those.
Here's the step by step:
1-
Remove the gas tank and disconnect both fuel lines from it.
2- Remove the belly pan.
3- Remove the left inner knee panel.
4- Remove the left fairing lower.
5- At the lower front of the fuel rail disconnect the fuel line that runs through the throttle bodies to the fuel pressure regulator.
6- Remove the right inner knee panel.
7- Remove the right fairing lower.
8- Remove the air intake snorkel.
9- Remove the three clips holding the upper and lower halves of the air box together. The right rear one is obvious. The left rear one is somewhat buried and is easiest to access it if you take the top coil cover off and push some wires out of the the way. The front one is "upside-down" and somewhat hidden on the front of the air box.
10- Push the foam heat barrier on top of the air box around to the front to allow a little more upward play in the top half of the air box.
11- Remove the air filter. Note that there is no lip on the left upper edge so the "easiest" way to remove it is to lift the air filter up at the back as much as you can and then pull it straight out to the right side of the bike. (If you're replacing the fuel lines then this is also a good time to consider replacing the air filter - or at least blowing some compressed air through it from the top to clean it out a bit.)
12- Remove the lower half of the air box. Unlike the earlier Ks, the lower air box on a K1100 is not bolted to the engine block so you can pull it right out. It's a bit of a wrestling match though given the tight space. What worked for me was pushing it forward a little, then rotating it counter-clockwise and pulling up and back and out at about a 45 degree angle.
13- Remove the fuel pressure regulator. It's bracket is mounted to the rear of the throttle body assembly at the top via two Phillips head machine screws.
14- Remove the Oetiker clamps securing the two fuel lines to the fuel pressure regulator. (I use a Dremel cutting wheel in the center of the "pinch.")
15- Cut your new fuel line to replace those two hoses. Note that generic fuel line won't have a pre-curved right angle in it on the one to the fuel rail so you'll want to make that one about a half an inch longer than the old one so that it doesn't kink where it connects to the fuel rail.
16- Connect your new lines to the fuel pressure regulator.
17- Reinstall the fuel pressure regulator. Note that the line from the fuel pressure regulator to the tank goes in between the "elephant trunks" for the #3 and #4 throttle bodies.
18- Replace the fuel line between the fuel rail and the gas tank with one of approximately the same length.
19- Put everything back together in the reverse order of how you took it apart.
