Raptor 30/50 v1 assembly manual
Page 2 [click here for index]

There are three pieces of fuel tubing used. The one going to the engine is referred to as the fuel line, the one to the muffler is called the pressure line, and the one that goes inside the tank is called the clunk line. The clunk line needs to be checked regularly because the exhaust gases cause the material to break down. The one that comes in the kit goes fast. Check it after the first dozen flights. It will become crystalized and when pinched, the inside walls will stick to each other. This will cause engine tuning problems because holes can develope and because the exhaust pressure can squeeze the line and reduce fuel flow. A good line to use for clunk line is the blue Aerotrend line. The pink Prather line works best for the fuel line and pressure line.

Begin by placing the clunk line(5) on the coned side of the fuel nipple (3). Next slide the rubber grommet (item 2) on. The big end will go toward the fuel nipple (item 3). Don't install it on (3) at this time. Next install the clunk (item 4) on the clunk line. Insert the clunk in the tank then fit the rubber grommet (2) in the larger hole of the tank. Put some fuel on the grommet to help slide item (3) in position. Usually what happens is the rubber grommet will be pushed into the tank. Don't use oil to make the fuel nipple go in easier, a lot of oils are petroleum based and will turn the rubber into goo. Another alternative is to place the grommet on the fuel nipple and use a flat blade screwdriver to push the bottom lip of the grommet into the tank. I have done this a few times, but be very careful not to damage the grommet. It is important that there be no air leaks anywhere.
Now that you have the clunk installed turn the tank upside down and confirm that the clunk does not get caught up on the back of the tank. If it does you will need to cut a little off the clunk line. You don't want the line so long that it gets stuck when doing 3D flying. But at the same time, don't cut it too short. When the tank is upside down make sure the clunk will fully reach the top of the tank. I have found on my 50 that the clunk line needs to be 85mm long

Go to Page 3