Handlebars won't stay straight. - 2006 Harley Davidson FLSTFSE Screamin Eagle Fat Boy

It's good to be careful, but can't tell over the Internet what the problem might be. Try taking it apart to see if you can detect the problem, or have someone mechanically handy look at it (including a bike shop).

I’m happy to help further over the phone at https://www.6ya.com/expert/donald_f2ed37026a3ac881

Not having the tensioner pulley lined up would do it.
All of the pulleys have to be in a straight line and the tensioner has to keep the belt tight, especially with extra load from one of the accessories.

Try with the kickstand up and check the kill switch on the right handlebar.

There are two sets of bolts here. The first one is straight up and down, is probably the one that takes and Allen wrench and is the one that tightens the handlebar stem - that's the pipe that goes down into the frae toward the front wheel. At the bottom of that bolt (inside the bike frame where you cannot see it) is a wedge-shaped nut that wedges the stem tight. If the stem is loose, then you will be able to stand in front of the bike with the front wheel between your knees and turn the handlebars side to side, and if it is loose enough you will be able to pull the whole stem right out of the bike. On the other hand, maybe you mean that the handlebars twisted down (so that the ends of the handlebars are pointed toward the ground - this would mean that the other bolt or set of bolts are loose. Some bikes have one bolt that clamps the top of the stem around the handlebars, and some have 4 smaller screws that do this. If this is where the problem is, then no, you don't need to buy the Allen wrench, but it sounds like you might need a bolt.

Is the run/stop switch on the right handlebar in the "run" position?

A major limitation is the steerer tube length. No matter how many times you cut a steerer tube it won't get longer.

Getting Riser Bars or simply flipping the stem over or getting one with a different rise and reach might give you the added height you need. If you LIKE the handlebars, the stem is the best and least-invasive option as most new ones come with front loaders (detachable front caps) that allow replacement without stripping components off one side of the handlebar. In minutes a Bicycle Shop could swap any number of them onto your bike for you to try.

If you had purchased the bike at a reputable Bicycle Shop they would have fit the bike to you before you took it home.

http://www.sheldonbrown.com/handsup.html

A major limitation is the steerer tube length. No matter how many times you cut a steerer tube it won't get longer.

Getting Riser Bars or simply flipping the stem over or getting one with a different rise and reach might give you the added height you need. If you LIKE the handlebars, the stem is the best and least-invasive option as most new ones come with front loaders (detachable front caps) that allow replacement without stripping components off one side of the handlebar. In minutes a Bicycle Shop could swap any number of them onto your bike for you to try.

Loosen the two bolts on the lower triple tree that clamp the fork tubes. Try to get the bars straight and then retighten the bolts.

Good Luck
Steve

Good Morning

The cable in the handlebar is not available as an individual item - to replace it you'll need the entire handlebar replaced.

If you are in the UK and the product is under 2 years old, please contact your retailer with your proof of purchase; They can either order a replacement handlebar for you to fit, or they can send your chassis to our engineers to fit a replacement, under the warranty terms and conditions.

If you are in the UK and the product is over 2 years old or you do not have proof of purchase you can order a replacement handlebar to fit yourself or book in the chassis for chargeable inspection and repair work required by phoning the customer service department on 01284 413 141 Mon-Fri 8.30-4.30. A replacement handlebar which will fit the 2007 model onwards is £50 plus £8 p+p. To book the unit in for the engineers to replace will be £60 and will include safety checks following repair work and courier delivery of the chassis back to your address. In addition to this you will need to make arrangements and cover costs for courier delivery of the product to our engineers.

If the product is a 2005 or 2006 model the current style handlebars do not fit straight on. In this instance the chassis will need to be sent to the engineers for them to provide replacement.

If you're not in the UK please visit www.quinny.com and select the country you're in, then use the "Contact Us" tab to be put in touch with the customer service department in your country.

Your front wheel is probably not tracking straight because your fork tubes are out of alignment. This could be caused because the upper and lower tube guides have been knocked out of alignment, because one or both fork tubes themselves are bent, or a combination of the two.

It's pretty easy to check the alignment of your tubes. Put your bike on its kickstand (center stand is better, if you have one) and stand in front of your bike, facing the headlight. Look carefully at where the fork tubes are anchored--they're clamped in right about the handlebars, and they're also clamped in below the headlight. Look at these two clamps and see whether they are completely in alignment. With your handlebars pointing straight ahead, the lower guides shouldn't be cocked to one side or the other. Odds are, you'll find that it will be.
Getting your fork tube clamps back into alignment is relatively straightforward, though straightening them out may also reveal bends in your fork tubes. The easiest way to get these into alignment is to remove your front wheel and then slide out your fork tubes. At this point, you should be able to loosen the clamp on the bottom (and top) of the steering tube--as if you were going to change out your steering bearings--and muscle the upper and lower fork tube clamps back into alignment. You can adjust the upper or the lower clamps (or both), whichever is easier; the goal is to get them both back into alignment.

Some people try to do this procedure with the fork tubes still in the guides--they loosen everything up and then use the forks as levers to pull everything back into alignment--but I haven't had great luck with that method, because the force that generates this condition also often bends the fork tubes, so they won't want to go back to their proper configuration. You and I simply don't have enough strength to straighten bent fork tubes without use of a hydraulic press.

Once your front fork tube clamps are back in alignment, check each of your forks before you re-install them to make sure that they aren't bent. One easy way is to take a straight edge (a ruler will work just fine) and slowly run it around the tube. The straight edge should touch all parts of the upper piece at all times. If you see any air between the straight edge and the fork, it's bent. Fortunately, many bent tubes can be straightened--just about any motorcycle repair shop can do this work or knows a place that can do it--but it's also worth checking around to see whether you can find a set of used forks for less than the cost of the repair. If you have to disassemble one or both of your forks to have the tubes straightened or replaced, it's also a great time to replace your fork seals while you're at it. Re-using the old seals probably won't generate a nice tight oil seal, and you'll simply have to take everything apart before too long and replace them.