Booster Plug on the BMW K1200R Sport

I recently purchased a 2007 BMW K1200R Sport.  As many folks report on the various web sites, some of these “wedge” bikes have fueling issues which leads to “snatchy” throttle response, surging at low speed and low RPMS, a “stumble” in the power curve at lower speeds and throttle and sluggish response from stop in first gear.

BMW has had a number of Firmware upgrade “fixes” that have solved some of the issue, but not all. And in many cases never to the satisfaction of many owners.

If you only ride this one motorcycle, you learn to live with the issues and you get used to them. But if you have access to other motorcycles that don’t exhibit any of this nonsense, it tends to drive you crazy!

There are two “fixes”. (Well three is you consider selling the bike and moving on to Japanese…..) But the two fixes are a Power Commander that lets you electronically change just about every parameter in the fueling system by way of the bikes onboard computer. A laptop computer and the use of a dynometer will usually get the bike running 100%. The cost for this can run upwards of $500 or more, depending on how much dyno and programming time you need.

The other option is to install various devices that ‘fool” the bikes computer into thinking it is always colder than it really is. This causes the bikes computer to enrichen the fuel mixture and run a bit richer. The whole reason these bike run poorly is mandated low emissions, and BMW’s failure to figure the whole thing out. BMW bikes since at least 2000 have had lean running issues and folks have been inventing cures as needed.

When you first start the bike and everything is relatively cool, the bike’s computer tells the fuel injection system to enrichen the mixture. But once the bike heats up the old emission rules come into play and the bike is leaned out to within an inch of its gasoline life. These add on “simple” devices fool the bike’s ECU into believing it is still cold and adding more fuel. Not much, but just enough to make things nice.

I decided to go with the “BOOSTER PLUG” http://www.boosterplug.com/shop/frontpage.html

This device is made in Denmark and shipped here to the states in very quick order. At the time of this article it cost $150. Lots of very positive reviews on various forums.

It consists of a simple electronics box with three wires:

Two of the wires contain matching plugs to the BMW  Air Intake Temperature (AIT) sensor sending unit and the third wire has a thermometer attached.

You simply disconnect the plug going into the motorcycles air-box and insert the Booster Plug into the circuit with this male and female plug. It is truely “Plug and Play”

Mount the temperature probe in an area that will always receive cool air and not affected by the bike’s engine or exhaust.

And you’re done!

On my bike, 2007 K1200 R Sport, I was required to remove the fuel tank to access the OEM AIT plug. But on many other BMW motorcycles the plug you need to access is much more available.

Once my tank was off, I located the AIT sensor plug against the rear of the air-box.

I disconnected the OEM plug and I connected the Booster Plug in series:

I decided to mount the temperature probe in the air-box, directly in line with the fresh air intake snorkel.

This required I drill a small hole in the side of the air-box:

Insert the probe and put some silicone sealant around it:

And there you have it: Done!

Put everything back together and go for a ride.

I had read somewhere that the ECU in these BMW bikes have some type of memory and you need to go through a couple start-stop sequences to have the computer “learn” the new settings. I have no idea if this is true or not, but I rode the bike a few miles, shut it off, restarted and repeated this three times.

I then went on a 50 mile ride consisting of highway and twisties and stop and go city riding.

I have no idea whether the felt improvement was psychosomatic or not.  But the bike felt very different. Zero bogging from a stop. Absolutely no surging at 35mph in 4th gear. MUCH more linear throttle responce when layed over in a corner at that 35-50mph range. The “snatchy” throttle is still there, but I’d be surprised if tis simple device could cure that. And I really didn’t expect it to.

I got up early this morning and went for another 75 mile ride. All of the felt improvements are still there! It’s a very different motorcycle. For the better!

So, more miles will tell, but my initial impression is that this Booster Plug works as advertised.

Lots more on the BMW K1200R Sport and other bikes and motorcycle projects here:

www.rvbprecision.com

And lots of photos and ideas here:

http://public.fotki.com/Rbertalotto/motorcycle/

 

Ride Safe!

UPDATE 9-5-11

I took the Booster Plug equiped bike to the Finger Lakes Rally in NY and a bit over 1000 miles.  The hole in the power band at 3000 rpms in lower gears is gone. The surging at highway speeds is greatly improved, but not completely eliminated.  At first I thought the slight surging I was feeling was wind buffeting, but I was on the road all by myself, totally stright for miles with near zero wind. At 75 mph there was still very slight surging. If I wasn’t looking for it, I might not have noticed it.

Surging at low speeds, while traveling through a town is completely eliminated.

The terrible “On-Off” (Snatchy) throttle is still present and is very annoying, bordering on dangerouis in the curves when riding aggressively. If this can’t be resolved, it could be a deal breaker on this bike. I’m sure if this was the only bike I owned I MIGHT get used to it. But I own and ride many bikes and none exhibit this characteristic. And even if I could learn to live with it, it won’t make for comfortable, predictable spirited riding.

At this point I’m going to live with the Booster Plug for a while, but I see a Power Commander in my future if I find it resolves the throttle issue.