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Discussion Starter #1
So I’m nearing the end of my first K1200Lt clutch journey and what a process it has been.
After a number of hiccups I finally put fuel in the tank and push the go button and the bike starts up and then struggles to idle cleanly. ~850
I can smell that it is running rich and (just off of idle) as I bring up the RPMs doesn’t run clean, but as the RPMs build it runs under what I would expect would be close to full power.

$h!T one more problem on a long rebuild. For certain this bike is unlike any other bike I have worked on.

So next some research on this website and I come up with a few things.

-Kevin12T had the exact same problem and after many trials and tribulations returned his settings back to stock (I have not changed mine at all yet) and replaced his air filter and all was good.
I replaced my air filter with a brand new K&N which may be to restrictive???

-My other thought may be that the oxygen sensor may be out because I cleaned it by spraying brake cleaner before re installing it.

-I also looked into the gas tank (as I replaced the in line fuel line and filter) to see if the fuel was moving from a fuel line leak in the tank as was suggested by another post and the tank with only a half gallon in it was just vibrating the gas so I don’t think that is the problem.

Aside from dropping the rear of the motor down without releasing the tension on the air filter couplings everything on the install went mostly as expected (with the exception of a wiring mishap).

I’m going to start with the K&N as I have a clean BMW filter available to install. Just didn’t want to mess with it for another 25K

Other than that any thoughts?
 

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So I’m nearing the end of my first K1200Lt clutch journey and what a process it has been.
After a number of hiccups I finally put fuel in the tank and push the go button and the bike starts up and then struggles to idle cleanly. ~850
I can smell that it is running rich and (just off of idle) as I bring up the RPMs doesn’t run clean, but as the RPMs build it runs under what I would expect would be close to full power.

$h!T one more problem on a long rebuild. For certain this bike is unlike any other bike I have worked on.

So next some research on this website and I come up with a few things.

-Kevin12T had the exact same problem and after many trials and tribulations returned his settings back to stock (I have not changed mine at all yet) and replaced his air filter and all was good.
I replaced my air filter with a brand new K&N which may be to restrictive???

-My other thought may be that the oxygen sensor may be out because I cleaned it by spraying brake cleaner before re installing it.

-I also looked into the gas tank (as I replaced the in line fuel line and filter) to see if the fuel was moving from a fuel line leak in the tank as was suggested by another post and the tank with only a half gallon in it was just vibrating the gas so I don’t think that is the problem.

Aside from dropping the rear of the motor down without releasing the tension on the air filter couplings everything on the install went mostly as expected (with the exception of a wiring mishap).

I’m going to start with the K&N as I have a clean BMW filter available to install. Just didn’t want to mess with it for another 25K

Other than that any thoughts?
Replacing the K&N with a paper filter is a good move but it won't fix this issue. A couple things to check and also a question or two.

1. are the 4 hoses all connected to the throttle body and not cracked:

2. Did you plug in the air temp sensor on the front left side of the air box?
Check to make sure it is plugged in

3. do the fans come on with the key on and motor not running?
If the fans come on, the engine temp sensor is bad/damaged or unplugged. It is on the back side of the left head behind the coil. You can see the plug in the picture where it can be tested.
If you lowered the engine without unplugging it, it will stretch the cable. a $120 mistake I will only made once.

4. Does it sound like it is missing?
The purge valve on the left side of the engine in front of the TVA uses the same plug as the injectors. Wires are green though. At least one person here has swapped an injector with the purge valve plug and it didn't run well.

You may need to find a GS911 to plug in and get some real time data or read error codes.
 

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So I’m nearing the end of my first K1200Lt clutch journey and what a process it has been.
After a number of hiccups I finally put fuel in the tank and push the go button and the bike starts up and then struggles to idle cleanly. ~850
I can smell that it is running rich and (just off of idle) as I bring up the RPMs doesn’t run clean, but as the RPMs build it runs under what I would expect would be close to full power.

$h!T one more problem on a long rebuild. For certain this bike is unlike any other bike I have worked on.

So next some research on this website and I come up with a few things.

-Kevin12T had the exact same problem and after many trials and tribulations returned his settings back to stock (I have not changed mine at all yet) and replaced his air filter and all was good.
I replaced my air filter with a brand new K&N which may be to restrictive???

-My other thought may be that the oxygen sensor may be out because I cleaned it by spraying brake cleaner before re installing it.

-I also looked into the gas tank (as I replaced the in line fuel line and filter) to see if the fuel was moving from a fuel line leak in the tank as was suggested by another post and the tank with only a half gallon in it was just vibrating the gas so I don’t think that is the problem.

Aside from dropping the rear of the motor down without releasing the tension on the air filter couplings everything on the install went mostly as expected (with the exception of a wiring mishap).

I’m going to start with the K&N as I have a clean BMW filter available to install. Just didn’t want to mess with it for another 25K

Other than that any thoughts?
I agree with Gordon's checks and recommendations.

K&N filters are not a good choice for a street bike. Personally, I would not use them even for off-road racing, but the shorter engine life isn't a big issue in a race vehicle.

I have always read that attempting to clean an oxygen sensor is generally a bad idea. Many different chemicals can contaminate the ceramic element inside the protective metal shield. Most sensor makers even caution against fuel additives as they can kill the sensor.

It may be that you just need some riding time for the ECU to relearn the fuel trim and TPS calibration. However, if you stay rich much above idle and this persists more than three rides, then I would replace the oxygen sensor. And if you oiled the K&N too heavily, that can wreak havoc with the oxygen sensor.
 
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I would do as Voyager said, replace the oxygen sensor. When you said you cleaned the oxygen sensor with brake fluid, that thought came to my mind instantly. I do not think brake fluid should be used on the oxygen sensor as it could ruin it.
 

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Discussion Starter #7
Replacing the K&N with a paper filter is a good move but it won't fix this issue. A couple things to check and also a question or two.

1. are the 4 hoses all connected to the throttle body and not cracked:

2. Did you plug in the air temp sensor on the front left side of the air box?
Check to make sure it is plugged in

3. do the fans come on with the key on and motor not running?
If the fans come on, the engine temp sensor is bad/damaged or unplugged. It is on the back side of the left head behind the coil. You can see the plug in the picture where it can be tested.
If you lowered the engine without unplugging it, it will stretch the cable. a $120 mistake I will only made once.

4. Does it sound like it is missing?
The purge valve on the left side of the engine in front of the TVA uses the same plug as the injectors. Wires are green though. At least one person here has swapped an injector with the purge valve plug and it didn't run well.

You may need to find a GS911 to plug in and get some real time data or read error codes.
1 I will check tonight, but I think everything is connected
2 It is plugged in but I will double check tonight
3 The fans do not come on
4 It only struggles down low, it revs nicely above 2k I will check the plug wires tonight
Thanks for all the great suggestions:grin:
 

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1 I will check tonight, but I think everything is connected
2 It is plugged in but I will double check tonight
3 The fans do not come on
4 It only struggles down low, it revs nicely above 2k I will check the plug wires tonight
Thanks for all the great suggestions:grin:
Before I rebuilt my oil soaked clutch, my LT would often (half the time or more) hesitate when coming off the line. I thought it was due to having to run E10 as the onset was near the time that my last local station dropped real gas.

After my clutch repair and several other things, the hesitation and sag on starting out was gone. Since I did several things that may have helped, I can't be sure what the real culprit was, but my money is on the oxygen sensor. Here are the things I did in what I think is decreasing order of likelihood of being the cure. Others may order things differently.

1. Replaced oxygen semsor with a plug compatible Bosch model bought from Amazon. I don't recall the number now, but can look it up if you need it.
2. Bypassed the pulse valve. I had removed the charcoal canister many years earlier and plugged the line, but if the line had a leak somewhere, the pulse valve could inject air into the intake. I bypassed the valve per instructions from Sailor to mimic the non-US bikes that lacked that nonsense.
3. Thoroughly cleaned the throttle bodies. They were dirty, but I doubt bad enough to cause my hesitation/sag coming off the line.
4. Replaced a badly cracked and leaking crankcase ventilation system. Since oil was leaking out, air was likely leaking in.

Of all these, I put 80% likelihood on the oxygen sensor as the culprit. Definitely worth $100 to find out (I think I paid $86 for mine two years ago). Riding my LT was not fun with the hesitation problem and a few times I didn't get the clutch in quickly enough to prevent a stall. I was nearly rear-ended a couple times. It is so much nicer when it pulls strongly away as the clutch is engaged.
 

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Yes forgot to add that I did the reset.
No change
Hey Tom, if you replace the O2 sensor, DON'T use the one designated for the K12 from BMW ($$$ - I know, shocker). There is a Bosch replacement you can get at most auto parts stores. The part number is Bosch 15738 (at least it was years ago for me). Exact same connector, just a longer wire.
 

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Discussion Starter #10
Before I rebuilt my oil soaked clutch, my LT would often (half the time or more) hesitate when coming off the line. I thought it was due to having to run E10 as the onset was near the time that my last local station dropped real gas.

After my clutch repair and several other things, the hesitation and sag on starting out was gone. Since I did several things that may have helped, I can't be sure what the real culprit was, but my money is on the oxygen sensor. Here are the things I did in what I think is decreasing order of likelihood of being the cure. Others may order things differently.

1. Replaced oxygen semsor with a plug compatible Bosch model bought from Amazon. I don't recall the number now, but can look it up if you need it.
2. Bypassed the pulse valve. I had removed the charcoal canister many years earlier and plugged the line, but if the line had a leak somewhere, the pulse valve could inject air into the intake. I bypassed the valve per instructions from Sailor to mimic the non-US bikes that lacked that nonsense.
3. Thoroughly cleaned the throttle bodies. They were dirty, but I doubt bad enough to cause my hesitation/sag coming off the line.
4. Replaced a badly cracked and leaking crankcase ventilation system. Since oil was leaking out, air was likely leaking in.

Of all these, I put 80% likelihood on the oxygen sensor as the culprit. Definitely worth $100 to find out (I think I paid $86 for mine two years ago). Riding my LT was not fun with the hesitation problem and a few times I didn't get the clutch in quickly enough to prevent a stall. I was nearly rear-ended a couple times. It is so much nicer when it pulls strongly away as the clutch is engaged.
2. Bypassed the pulse valve This is intriguing. I performed a can ectomy, perhaps I did not block off the line well enough?
I'll have to look at it. Seems like the most likely culprit but I will check the others as well.
 

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Discussion Starter #11
"Not" working from home today so I had to get out there and see if the can ectomy hose was leaking. And it's tight with a bolt and ziptie in the end.

So while I was at it I looked at the other recommendations
Coolk1200:
1 Yes connected and in good shape
2 Yes plugged in
3 No No fans going
4 Not really missing, just struggling

Voyager:
1 Am leaning towards that too. Damn just trying to clean things up
2 Had to check but everything looks good. big bolt with ziptie Really hoping that was it.
3 I cleaned the throttle bodies before reassembling. They were in pretty good shape though. The bike only has 25K
4 I'll have to check and see where they are located, but this bike did a lot more resting then riding my feeling is that the hoses should be ok
 

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Discussion Starter #12
4 Not really missing, just struggling
And I checked the wires on the injectors and all four are the same color.
 

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Double check that there is no interference on the throttle bodies due to clamp placement. If you had them off to clean make sure ALL return springs are hooked up and movement is free. I had one that ran like crap and finally traced it to one of the springs had popped off the butterfly and would not allow the ECU and TPS to read the expected value at closed throttle. Reinstalled the end of the spring and she purred like a kitten.
 
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It is possible that is your problem but you can actually start a cold LT with the O2 sensor unplugged and it will idle fine.
 
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I've ordered a new O2 sensor so we'll see how it runs in two days when it arrives.
$85
Tom, you're a wealthy guy. At that price, you should have ordered 2!! >:)>:)
 

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I've ordered a new O2 sensor so we'll see how it runs in two days when it arrives.
$85
The 13475 I hope. $76 now at Amazon.

The fun part can be removing the old one. I heated my pipe up with a heat gun and then soaked it well with WD-40. Let it soak overnight then heated it again, applied more WD and hit it with the 1/2" breaker bar. Mine came right out with just a couple of palm whacks to the breaker bar. I was lucky.
 

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It is possible that is your problem but you can actually start a cold LT with the O2 sensor unplugged and it will idle fine.
My LT idled pretty well after I rode a hundred miles or so to let the ECU get its bearings. The TPS reset never seems to do squat for my LT. It always takes a few rides to idle well after the battery is unhooked for any length of time.

My hesitation/sag was worse when the bike was up to temp and worse yet in hot weather. The strange thing is mine was random. That is why I suspected the pulse valve more so than the oxygen sensor as my car experience is that the latter dies and stays dead rather then becoming intermittent. I don't know the pulse valve algorithm, but expect it operates only periodically. However, I just can't believe the pulse valve could admit enough air to cause the issue I was seeing.

All I know for sure is that the problem disappeared somewhere along my clutch repair journey. And for that I am grateful!
 

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Discussion Starter #19
Tom, you're a wealthy guy. At that price, you should have ordered 2!! >:)>:)
Guilty as charged, that's why I like to invest all of my big bucks in an 18 year old bike. Because as an investor I can tell you the Return On Investment is going to be spectacular. :wink:
 

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Discussion Starter #20
The 13475 I hope. $76 now at Amazon.

The fun part can be removing the old one. I heated my pipe up with a heat gun and then soaked it well with WD-40. Let it soak overnight then heated it again, applied more WD and hit it with the 1/2" breaker bar. Mine came right out with just a couple of palm whacks to the breaker bar. I was lucky.
76 plus tax. I took the old one out, cleaned it lubed it with copper and reinstalled it so putting a new one in should go smoothly. But I'm always optimistic, sometimes to a fault apparently
 
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