Wunderlich Comfort seat and the Nelson-Rigg Commuter Tail Bag

Base plate: Stock (left), Wunderlich (right)

I recently picked up a Wunderlich Comfort seat (tall version) for the F900XR. I had been using a Nelson-Rigg "Commuter" tail bag on the stock seat, and found that the profile of the Wunderlich didn't match well with the tail bag. To be fair, the Nelson-Rigg didn't really fit well on the stock seat as it projected out over the lip between rider and passenger seats. I found a way to mount it that I think works quite well.

First off, impressions on the Wunderlich. It's built on the same base plate as the stock seat - as far as I can tell, they must be buying the base plates from BMW or their OEM vendor. Aside from a lack of BMW part number stamps, it's the same plate. One downside is that the stapling on the Wunderlich isn't done as well as the stock - the BMW stock seat's staples are larger and applied in a very clean line, with a piece of reinforcement fabric between the staples and the seat material. The Wunderlich staples are smaller, less carefully applied, and there's no reinforcement fabric. Given what I paid for the Wunderlich, this was disappointing.

Wunderlich included a couple of odd fabric chunks over the seat lips, and I have no idea if they're included simply for shipment protection, or if I'm supposed to keep them on the seat after install. If the latter, think the technical term for these covers is "A framitz which I'll lose within an hour of riding."


Top side: Stock (left), Wunderlich (right)


Wunderlich Seat Framitz (Patent Pending)

On the top side, the profile of the Wunderlich is more sculpted, and the stitching is stylish. There's more room to the rear, and the groin area is higher but also narrowed from stock. I got the "tall" version which helps reduce hip flexor and knee stress.


Straps can only go one place, really

Unfortunately, the extra space on the rider's seat also further reduces the passenger seat area, which aggravates the problem of the Nelson-Rigg tail bag (and that damned "backpack" D-ring) intruding into the rider seat and rattling against my butt. This needed to be corrected. The Nelson-Rigg standard "clean installation" process (video) is to loop both straps under the seat, then lock down the seat. The problem is that the BMW seat plate has bumpers, so there's really only one way to do the install. If you push the bag back, the straps block the bumpers. Push it back farther, the straps get in the way of the seat's locking post.

Looking around the tail section, I realized that there are slots in the body work for...luggage? There's a slot on each side, and a void behind the toolkit and storage pocket. I figured I could slip one set of straps through the slots, and that would allow me to push the tail bag to the rear. The problem was the way Nelson-Rigg joins the straps together is to loop them together - this creates a somewhat large knot that doesn't want to pass through the body panel slots.

So I decided to make use of the passenger handles - with the tail bag on, nobody's back there anyway. I removed the toolkit, slipped the straps through the body panel slots, then hooked the loops over the front section of passenger handles. (You want to use the front section, because when the straps are pulled tight the loops will not slide off the handles.) These straps will go onto the rear tail bag buckles.



Rear straps on the front of the handle

Front straps now in between bumpers

Next, I did the standard Nelson-Rigg install on the front buckles, but with the tail bag slid backwards, between the bumpers. The tail bag hangs off the back of the seat a bit, but that's fine because (as you'll soon see) the tips of the passenger handles support the bag. Attach the seat and tighten the straps.

End result: Tail bag is now set back, away from the rider seat. I tucked the excess strap up into the body panel slots to create a clean look.


No more butt-tickling D-ring



Shiny! Note how passenger handles

support the bag's rear edge

F900XR Hand Grip Replacement

 I'm 6' 6" with large hands, so stock hand grips don't work well for me.  One of the first modifications I made to the F900XR was to replace the stock grips.  As it turns out, this wasn't a simple modification.  

The problem, as I noted in my opening post, is that there's not a lot of information on the F900R/XR models.  So I started the grip replacement process presuming that it would be like the dozens of grip replacements I've done in the past.  I was wrong.

Disclaimer: This modification involves literally cutting up parts of your bike that are adjacent to - and can adversely affect - the throttle, the BMW thumbwheel, heated grips, etc.  This procedure was written based on a bike that doesn't have heated grips.  If you damage your bike, launch it over a cliff, injure yourself doing the modification, etc. it's not my fault.  Don't attempt this if you're not confident in your own skills, and triple-check everything before you ride the bike again.  

For some reason, BMW product engineers decided - contrary to the way motorcycle grips have been attached to handlebars for decades - that they would bond the grips to the throttle assembly .  This makes absolutely no sense - what happens if the bike is in an accident, or the grips eventually wear out from use?  What kind of engineer would effectively make the grips a permanent part of a bike?  My theory is an engineer who's never worked on a motorcycle.  Or it was simply schadenfreude.  

Normally, you start by cutting into the old grip, peeling it away from the throttle body, and then scoring with a razor knife as you pull it away.  This is especially important if you have heated grips, as you don't want to cut into the heater elements.  Adventure Tejas has a video that describes the process for BMWs fairly well.

Shortly after I started cutting into the pommel or "butt" of the throttle-side grip, I knew something was wrong.  The grip rubber would not separate from the underlying throttle assembly.  I tried to call the BMW dealer that sold me the bike - a service department guy said he thought the grip was "laminated" to the throttle assembly but had no suggestions other than "I think it might be hard to do."  Great...

Turns out, yeah.  The grip is bonded to the throttle assembly.  Not glued.  Bonded, as in thermally.  It will not peel off.  It must be shaved off.  To do this, you'll need a box-cutter, a flat razor like you'd use for cleaning paint off glass, and a pair of vise grips.  Use fresh blades - you want to make sure you can easily cut into the rubber without damaging the underlying plastic.  And wear gloves to avoid cutting yourself.

Start by removing the bar-ends with a T50 bit.  Place a towel on the bike's body work, so that rubber chunks don't fall into the body panels or engine space.  Place a small trash can or bucket under the grip to catch rubber chunks as they fall off.  You won't get them all, but it helps.

Work on a small section at a time, starting at the end of the bar.  Pull the grip rubber away gently with the vise grips and use the razors to separate the rubber from the throttle assembly.  

Try to keep the razor blades flat against the throttle assembly, effectively shaving the grip away in strips a bit at a time.  Take your time and don't rush.  

Once you have the grip shaved down, you can install the new grip.  I installed Trackside foam grips, so I can't say if this will work for other grip types.  Using a towel to protect the bike, coat the throttle assembly with hair spray - this will act as a lubricant then dry into an adhesive.  I guess you can use grip glue - in my opinion that's just overly-expensive hair spray.  I have two daughters at home - there's a lot of hair spray to be had for free.  

You'll need to work quickly at this stage, or the hair spray will dry.  Push the grip towards the bike's center line and twist forward as you go.  Don't push the grip too close to the throttle assembly housing, or it might not return to idle on its own.  Give yourself a couple of millimeters clearance, and test that the throttle returns reliably to the idle position.  I can't stress enough how important this is.  A stuck throttle could kill you.  

The process for replacing the left-side grip is more standard.  As it turns out, my bike has a grip heater installed but not wired.  I guess the factory prefers to use a single part number for all bikes - probably simpler that way.  You can follow the Adventure Tejass process linked above to remove it.  Again, I don't have grip heaters, but if you do make sure you don't cut into the heater wiring.  I found that the left-side grip was thermally molded in several places into the grip heater assembly and had to cut or rip those points away.  

Installing the left-side grip is essentially the same as the throttle-side grip, but you need to consider how the new grip might affect the BMW thumbwheel on the F900R/XR.  The pommel/butt of the factory grip is eccentric, it's designed to line up with the thumbwheel which isn't concentric with the handlebar.  You also don't want the new grip to prevent the thumbwheel from rocking or turning, nor do you want the new grip to push on the thumbwheel by itself.  As with the throttle-side grip, you want to leave a couple of millimeters gap between the grip and the thumbwheel.  

I'm going to presume that the thumbwheel assembly is waterproof, as the grip wasn't sealed against the thumbwheel, but this is a guess.  A small part of the thumbwheel is showing outside the new grip's pommel/butt, so I'm taking a calculated risk here.  

In the end, this worked out fairly well, but I'm still amazed that BMW would build a grip system that can't be easily modified.  If you're building a bike that's designed to last decades, you have to expect that you'll need to replace grips at some point.  I'm at a loss to explain why they did this.  

Another Blog?

 

You might ask why I'm creating a new blog.  Isn't my other blog ostensibly about hacks and how-tos?  Sure.  I just think the topic of motorcycles deserves a focus.  

After a lot of shopping and consideration, I bought a 2020 BMW F900XR.  There's a lot I like about this bike, but there are things about it that are frustrating.  I chalk this up to the bike being fairly new, especially to the U.S., so there's not a lot of information about the bike.  There are a lot of accessories available to buy for it, but (for example) not a lot of information about maintenance and modification.

I've been working on motorcycles for over 40 years.  At one time I worked in a motorcycle shop, and I've restored and modified more bikes than I can count.  So here I am with a new motorcycle and no shop manual, no service manual, etc.  I don't even know the torque specs for most of the hardware.

Fortunately, there are some - albeit limited - resources.  There's a Facebook group for F900R and F900XR owners.  The engine (which is actually made in China by Loncin to BMW specs) the F900R/XR is essentially the same as the F850GS, so there's some limited information such as oil changes that can be applied to the R/XR.  It's not much.  In the interest of helping other R/XR owners, I'll do what I can to share information here as I uncover it.