HarleyMotorcyclePartsReplacing the Fuel Line on a Tri Glide Ultra (FLHTCUTG)
Three wheels take away a trick two-wheel owners rely on, and the two-wheel line may not be right.
Two-wheel Harley owners carry a habit into this job that stops working on a trike. They lean the bike or shift it on a stand to bring a fitting into view and steer drips away. A Tri Glide stands on three wheels and goes nowhere. You have to bring your body to the fitting instead. Worse, what you learned on a two-wheel Ultra may not match, so do not assume the routing or the fittings are shared.
Tools
- Trike service manual for your exact year
- New line confirmed for the trike
- Replacement O-rings
- Disconnect tool that fits
- Lidded container for gasoline
- Extinguisher that handles fuel fires
- Creeper or kneeler
Start with the book, not the bike
On most guides on this site, the manual is where you confirm a figure. Here it is where you learn the job. Trike-specific routing and fittings are in your service manual, and they take priority over anything written below, including our general outline. Get the one for your model year, not a general Touring volume.
Check your parts the same way. Seeing an FLT code in a listing means the line fits certain two-wheel bikes. It does not by itself confirm that it suits your trike. Look for your own code and year, and ask us before buying if you cannot find them.
Confirming the fuel system
The Tri Glide row we cover is EFI, with an in-tank pump and a quick-connect line. A quick look confirms this: a sliding-sleeve fitting at the tank and no petcock. A brief pump sound at key-on is the second confirmation. If you find a petcock and a carburettor, somebody built something unusual, and you need to work from what is there rather than from this page.
Setting up around a bike that will not lean
With no lean available, gravity decides where any spill runs, so look at the floor beneath the fitting before you begin. A catch tray and absorbent go directly below, and the sealed can sits beside you.
Wide bodies also limit your exit. Think about where you will stand or kneel, then position the extinguisher so that you never have to squeeze past the machine to get it. It should be rated for burning fuel. Choose a spot in the open air if you can, or one with serious ventilation, because vapour gathers under a low, wide machine. Cold engine, cold pipes. Absolutely no pilot lights, grinders, cigarettes or sparking lamps.
Holding a trike still
A motorcycle lift is not the right tool for this machine, and you should not need to raise it for a fuel line unless your manual says otherwise. Park on level, solid ground, with the wheels secured so that it cannot roll while you are climbing around it.
Remember how much bigger and heavier this is than anything on two wheels. Rear body panels may have to come off, and those get a padded spot well away from the fuel. Do not rest parts on the body, and do not kneel where a spill would run toward you.
Depressurise, isolate, then open
Purge first, in the way your manual specifies. Commonly that means pulling the pump fuse or connector, letting the engine run or crank to a stop, and keeping the pump unpowered. Harley's documents refer to this as purging the line of high-pressure gasoline. Allow time to cool if it ran.
Take off the negative battery cable next and secure it clear of its post. Now the system is neither pressurised nor powered, and this is the earliest point at which any fitting may be touched.
The replacement itself
Follow your manual on whether the tank is raised and what comes off to get there. A trike has extra bodywork at the rear and its own hardware, so never guess at this. Protect paint as you go.
At the fitting, hold absorbent beneath, slide the sleeve with the push-pull motion the book describes, and separate the line slowly. Plug the opening.
As you take out the old line, photograph how it runs, including any clip you could not see from above. Then lay old and new together and compare every bend. A mismatch here means the wrong part, and it must go back unfitted. Forcing a line into shape strains its joints.
New O-rings at each connection, since the old ones are single-use and are the common source of leaks. Press each fitting until it locks, and pull against it to confirm. Return all clips, and keep the line off hot surfaces and away from anything that moves.
If the original line is damaged and the right part is days away, the trike waits. Rubber hose and a worm clamp will not hold on a high-pressure feed, and it is not a get-you-home option.
Testing before the motor runs
Pump power restored, then battery last. Key on, thumb off the starter. As the pump primes and stops, shine a light on each joint from below as well as above, since you cannot tilt this machine to see. A small mirror makes that easy. Then look at the tray. Repeat the cycle a few times.
When the tray and the joints are both dry, start the engine and check again, then again warmed through. If what you need is a line inside the tank, that is a separate job, set out in our Fuel Filter and Fuel System Service guide.
Mistakes that cost money
- Using two-wheel Touring routing from memory or from a video.
- Buying on the strength of an FLT code without checking the trike is listed.
- Placing the extinguisher where the wide body blocks the path to it.
- Leak-checking only from above.
- Bending a line that does not match until it fits.
When to stop
A trike-experienced shop should take over if the manual and the bike disagree, if your parts source cannot confirm the line, if the machine is a conversion, or if any leak returns after a redo.
Other Harley how-to guides
This guide covers procedure and judgement. Torque figures, fluid capacities, gaps and tension settings are specific to your model and year and must come from the factory service manual for your motorcycle — we deliberately do not print numbers we cannot stand behind for your bike. Independent aftermarket retailer, not affiliated with Harley-Davidson, Inc.