Help Diagnosing a R1100R Problem

[blackjak04]

I'm relatively new to riding and have been fortunate enough to be able to ride an '01 R1100R. The bike has has only been ridden a handful of times since it was purchased new a few years ago. The only maintenance I've done to it has been maintaining the battery and changing the oil.

 

The problem I'm having is that every time I go for a ride, even if its only a few minutes around the neighborhood, The exhaust and lower section leading to the exhaust pipe heat up until they are literally bright glowing red hot, hot enough to where it looks like someone has held a blowtorch to the exhaust system for the last 30 minutes until it literally begins to glow like the color of lava pouring out of a volcano. I understand that the pipes can get super hot, enough to burn you if your not careful, but this is to the point of glowing bright red. Whatever the problem is, is seems like its something fairly simple to correct and even though I've been wrenching on cars for a while now, I don't know the first thing about what could be causing this on a bike.

 

I've heard people say running the bike rich for to long when you first start it up can lead to combustion all the way back in in the exhaust section, but even when I don't use the choke at all, the same problem occurs.

 

If anyone has any advice it would be great appreciated.

 

 

The lower square section of the exhaust is what usually begins to glow bright red

[Joe Frickin' Friday]

First check: are the short throttle cables firmly seated in both the throttle bodies, AND in the junction box under the fuel tank?

 

If they're fine, then take the next step. You've got an '01, so this will work for you. Click here, and go to page 71 to find out how to read the fault codes in the Motronic. At least one cylinder (possibly both) is running way too rich for some reason, and all that extra fuel is cooking off in the cat (the square section of your exhaust).

[Ken H.]

As Mitch said, the bike is running way too rich for some reason, and it could one of several different things. The first step is a though tune up including a throttle body sync check.

[Tipover_Bob]

As Mitch said, the bike is running way too rich for some reason, and it could one of several different things. The first step is a though tune up including a throttle body sync check.

 

Ken:

Could the TPS setting cause this?

 

Tipover Bob

[Ken H.]

As Mitch said, the bike is running way too rich for some reason, and it could one of several different things. The first step is a though tune up including a throttle body sync check.

Ken:

Could the TPS setting cause this?

 

Tipover Bob

Yes that would be one of the things on the list to check.

[blackjak04]

guys, I really appreciate all the help. still no obvious answer yet. Im about to pull the codes from the mototronic? which I assume is the ecu, and I'll let you know what faults its showing. Then I'd like to check the TPS setting except I have no Idea what that is. any help would continue to be apreciated. Thanks

[ShovelStrokeEd]

Before getting all involved with TPS settings and whatnot, I would have a look at the injectors themselves. Reasoning is that this is grossly rich, not just a matter of a few % points rich as a mal-adjusted TPS would give. Prime two suspects would be a leaking injector of a failed fuel pressure regulator.

 

Remove the injectors one at a time, they are held in place by a little plate which bolts to the throttle bodies with a couple of socket head cap screws. With the injector pointing into a bucket, turn on the ignition switch and allow the fuel pump to cycle, pressurizing the system. There should be no fuel coming from the injector at this point. Now, bump the starter button for a couple of seconds. The injector should give one good squirt and then settle down to one squirt per rev, quite probably a bit less than the initial one. Note: There shouldn't really be a lot of fuel per squirt. If it is excessive, see below.

 

There are a couple of failure modes for the fuel pressure regulator that can cause this. One is not really the regulator but rather a pinched or kinked return line. This will cause excessive pressure in the line.

The second mode is a failure of the regulator to open and bypass pressure once the system comes up. Again, excess pressure in the manifold.

 

You can determine if the line is open and bypassing fuel by raising the tank and disconnecting the lower of the two lines coming out of the fuel pump mounting plate. Aim it into your bucket. Turn on the ignition switch and crank the motor, the fuel should come in a pretty steady flow from this line.

 

BIG CAUTIOM!!!!!!!

You are dealing with gasoline here. Its vapors are highly flammable and toxic. If you are at all unsure of what you are doing, take the bike to a dealer and let him fix it. Burning yourself and your house down is not the best way to spend a weekend.

[carquestman1]

Excuse me guys. I'm new to the forum so please correct me if I'm wrong and my expertise is not really BMW motorcyles but automotive. However my experience with super heated exhaust is normally because of a lean burn situation usually caused by something as simple as an intake leak or bad air flow sensor somewhere. The super heated air is causing the cat to glow red. Unless there is raw gas in the cat I don't think your dealing with a rich condition here. And if there is raw gas in the cat watch out, raw gas super heated causes explosions. Lean burning engines can cause big time damage to pistons and valves if not corrected. Just something else to ponder.

[Joe Frickin' Friday]

Excuse me guys. I'm new to the forum so please correct me if I'm wrong and my expertise is not really BMW motorcyles but automotive. However my experience with super heated exhaust is normally because of a lean burn situation usually caused by something as simple as an intake leak or bad air flow sensor somewhere. The super heated air is causing the cat to glow red.

 

If this was the case, one would also expect to see red-hot header pipes, straight out of the heads. The OP included a pic from the manual (see below) and indicated "The lower square section of the exhaust is what usually begins to glow bright red:"

 

 

 

SS-Ed sez:

There are a couple of failure modes for the fuel pressure regulator that can cause this. One is not really the regulator but rather a pinched or kinked return line. This will cause excessive pressure in the line.

 

Seems like a quick-and-dirty check for this would be to listen to the fuel pump at key-on. When my fuel line popped off inside the tank at Cody in '04, at key-on the pump could be heard to spin faster (and more quietly) than normal since it was not building any pressure. If the pump instead is laboring against a blockage, one would expect it to spin much more slowly and noisily than normal at initial key-on.

[blackjak04]

Ed,

Thanks for the suggestions, I've replaced injectors before so I'll check it out and let you know what I find.

 

Someone else also suggested to me that the bike is running lean and I didnt understand why they thought that until it was just explained, but no the headers appear to remain at normal temperature so I don't think thats it.