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.