NOTE: After forever-and-a-day, I have finally written up an accompanying HOW TO thread for swapping out the stock Crossbones fender for that of a Heritage Springer/Springer Classic. Find it here: https://www.hdforums.com/forum/softa...l#post10012404

Lots of us Bones owners have contemplated switching out the rear fender for something that fits the overall style of the bike a little better or that at least does not clash so much. I actually became a member of H-D Forums when it occurred to me to Google the idea of putting a Fatboy rear fender on the back of my scoot. The search yielded a number of threads here on the forums and I promptly signed up to be a member so that I could ask questions to those who had made the swap and to see how feasible it was to do. The obvious answer was that it could be done. However, there were a lot of little details that I wanted to ask about before I realized that I would just need to attempt the swap myself and figure it out as I go. The best prep I could do was to study the parts manual and service manual for both bikes and see what was the same and what was different. Once I had this info I purchased whatever I needed including the fender and jumped to it. I decided to try and document the swap so that I could share it here on the forums and hopefully help someone else out down the line as much as others have helped me get to this point. I plan to update this thread if I miss anything or to offer part numbers where applicable.

What you will need:
2007 or later Fatboy rear fender that fits Softails with 200 mm rear tire. I got mine on eBay. Brand new take-off from a Fatboy-Lo with tag bracket and tail light lens assembly for $300 shipped.
Tail light assembly that will fit the Fatboy fender. If you don't mind the stock Fatboy tailight then get the tail light Base Assembly part #68066-99A-$39.99 and use your stock Xbones lens assembly.

Here is the link to the eBay listing where I got my tail light base. If you want to go this route then here is a really cheap way to get this part. Then you can just use your stock tail light lens and plug. http://cgi.ebay.com/ebaymotors/ws/eB...=STRK:MEWAX:IT

License plate bracket that will fit the Fatboy fender.
Rear inside mounting bracket (X2) for Fatboy fender. Part# 59088-03-$4.99 each (X2) (I understand that you can use the stock Xbones brackets but they have to be cut in length in order to fit.)
Wire retainer clip plates (x2) for Fatboy fender. Part # 45550-03-$1.99 each (X2)

If you plan on sticking with your sprung Crossbones seat then the above should be pretty much what you need and everything else for the swap will come from your Bones. However if you want to run any sort of Fatboy type seat with your new set up then you will also need the following:
Seat stud plate. Part # 51803-07 $8.99
Large nylon washer Part # 7434-$1.99 each (x2)
Seat thumb screw part # 3633-$4.99 each (x2)

I will mention specific tools and supplies along the thread but for the most part you will need a basic set of standard sockets, wrenches, ¼ and 3/8 drive ratchets, and screw drivers. A motorcycle lift or a way to get your motorcycle lever and not on the jiffy stand is a huge bonus!

After taking a last look at my stock Bones I proceed to lift her up and strap her down for the swap. The seat and seat pan come off and the rear fender is cleared of the saddlebags, pillion, and sissy bar.

Disconnect negative battery cable and wrap the end in electrical tape. Unplug the rear light wiring harness as well as the ECM module. I went ahead and removed my ECM module with plate before taking the fender off in order to remove as much weight as possible. I used one of those magnetic wands to retrieve the stud plate from underneath the fender after I removed the two 3/8 nuts that hold the ECM plate to the fender.

Using a T45 torx bit with a 3/8 drive ratchet loosen but do not remove all the bolts on both sides of the fender. Before I tried removing the fender off all the way I protected the top edges of my oil tank by stuffing a cloth between it and the frame. I also stuffed some old towels and rags underneath the fender and on top of the rear tire to keep the fender from dropping down so far when I unbolt it completely. If you can, get someone to help you hold the fender while you unbolt it. I did this on my own so I had to take extra precautions.

 

Once the stock fender is off turn it over and begin salvaging the parts you will need to keep. This includes the two front inner fender brackets, the wiring harness with foam conduit, the plastic wire retainer clips, and of course the inner and outer fender struts as well as the ECM stud plate and any fender seat nuts you may have used. These would be the same as the ones used to bolt the top part of the ECM plate.

Move the stock fender out of the way and begin installing the parts onto the Fatboy tin. I used GOOP to glue the wiring harness in place. Before I did this, I installed the Fatboy tail light base so that I could actually plug in the harness and make sure it was going to be long enough.

While the glue set, I extended the turn signal wires by 7 inches. You could probably get away with 5 or 6 but I like to make sure that I am not stuck with wires that are too short. I used a soldering iron to make my splices since it made for smaller neater connections. I used heat shrink tubing to seal everything up.

 

Assemble the new parts as well as the stock parts from your old fender onto the new Fatboy fender. The wire retainer plate (part # 45550-03) fits between the rear fender bracket (part #59088-03) and the inside of the fender. The wire clips on the plate should go towards the back of the fender. Leave the tail light lens off until you test your lights. Also, leave the ECM off unlike it shows in my pic. During the process I ran into an issue down the line. The ECM has to be plugged in before it can be bolted back into place.

If you are working alone, it can be ticky trying to line up the fender struts to the fender and get the bolts started without banging things around and ruining your nice paited and PC'd parts. The best thing that I found to get the fender struts onto the new fender was to prop the front of the fender up high enough using stacks of shop towels and rags until the hole pattern was horizontally level. This allowed me to line up the fender struts to the bolt holes without trying to hold the fender up with my other hand. The rear inner fender brackets are held in place by a 9/16 flange nut but the front inner fender brackets have nothing to hold them in place before assembly. Since I needed one hand to hold the fender struts and the other to start the bolts, I used tape to hold the brackets in place on the inside of the fender.

As I tested the lights I realized how good it was that I extended the turn signal wires as much as I did (7 inches). When I tried the turn signals I was surprised to see that activating the left switch worked the right signal and the right switch operated the left signal. Essentially they were reversed. As I thought the problem through I quickly realized why. The circuit board in the Crossbone is technically upside down. When using the stock Fatboy tailight base, the circuit board in it is right side up which reverses the plugs causing them to be backwards. The solution is simply to switch the plugs; cross the right plug over and plug it in the left port and cross the left one over and plug it to the right port. The extra length I added to the wires made this totally possible.

 

I had read on other threads that the ECM had to be STUFFED in order for it to fit. I found out why. It sits just a bit lower on the Fatboy fender. This will not be an issue at all if you are running a Fatboy style seat. However, if you want to continue using the Xbones sprung seat you have to modify the bracket that is bolted behind the battery. Essentially, the bottom of the ECM plug can not clear this bracket and this prevents the ECM from being properly mounted. You could just tighten the bottom two bolts just enough to make it snug but I did not like how that worked. In addition to putting undo strain on the ECM plug, it forced the top of the mounting plate against the fender which might cause wear over time.

I decided that it was worth it to notch out the seat bracket in order for the ECM to fit properly. You still can't plug and unplug the ECM without unbolting it first but at least this way it will fit as it should when you mount it.

 

Great thread skeez, modders will know that you will need a a good quality T45 torx bit to loosen / remove the bolts on the side of the fender. It also helps to have a decent length wrench to crack the sealant on the bolts as these can be quite tight.
Also do you have any tips on unplugging the indicator wires from the tail light, I couldn't work it out when I did my indicator relocation and ended up snipping them?

 

Although I am currently running my sprung 1925 seat, I plan to run other seats and set ups for two-up duties which is the main reason I did this mod. Below is my finished scoot and how it looks with either a stock Softail Deluxe seat or a Fatboy Lo seat and Pillion.

Of course at this point it is up to you what type of tail light, tag bracket and turn signals you decide to use. I went with stock stuff for now since it was cheap and it allowed me to make the conversion and get me on the road while I take my time deciding on what the final set up will be.

I will continue modifying this post with details and updates. If you have any questions just ask. Also, if you are a Fatboy owner and have any insight to offer it would be greatly appreciated.

Hope this helps!

Skeez

 

Best write-up I've ever seen. Nice job man!

 

Great detailed write-up!
nice pictures and captions!

CC

 

Thanks! Will be most helpful in the next couple of weeks!

 

Man I wish I had that when I did mine. Great job.
Coyote