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Discussion Starter #1
2000 K1200LT
I have an exhaust pop. As I use the engine to brake into a curve or coming to a stop with the throttle closed, when I open the throttle at all I get a fire cracker type of pop. Now this happened with the stock exhaust and stock air filter. It continued to happen with the addition of a K&N filter. It still happens with the now installed Remus pipe and I even installed new exhaust gaskets. I almost decided to add the power commander but after talking to a one very knowledgeable tech help line there is no guarantee that the pop would go away with the addition of the power commander. He said he has tried to remove the pop and to this point "no luck". The bike seems to run just fine but the pop just is annoying.

Anyone have a fix/input
 

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Are you running 5000+ RPMs and engine braking?

I'd try using more brake and less engine brake to stop.
 

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2005 K1200LT
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Sounds like you have done a lot already but I have to ask - Have you reset the Motronic and then reestablished the TPS setting for full open and full closed?


After the reset (pull fuse) turn on key - no start- throttle full open then closed twice then turn off key. Now start normally.
 

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From the Chilton manual: Engine Backfires on Deceleration:
If the engine backfires when the throttle is released, check the following:
1) Faulty Motronic control unit. (try resetting the Motronic as advised above)
2) A loose or damaged seal between the cylinder head and exhaust pipes.
3) Check the following engine components:
a. Broken valve springs.
b. Stuck or leaking valves.
c. Worn or damaged camshaft lobes.
d. Incorrect valve timing due to incorrect camshaft installation or a mechanical failure.

Not terribly helpful, I'm afraid. Hopes it is just the Motronic needing to be reset.
 

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Discussion Starter #5
I would say the braking is not extreme and high speed is not needed.

I reset my TPS after I replaced battery.....
when I was done replacing the clutch :)
I have been lurking a while but this was my first post.

From what the power commander tech said it has to do with the computer shutting down the fuel with the throttle closed, as soon as it is reopened is when it pops. He has dealt with it before and had no luck using the power commander to correct the problem. He made it sound like it was common but the pipe makes it more pronounced. The valve train is fine and I even replaced the plugs with Iridium NGKs just because I could.....the old plugs were fine.

Now here is an interesting tidbit I had not mentioned. When the engine is cold (read rich) it doesn't do it. When I talked with the tech I called it a lean back fire and he said that was not the case. I will come up with a fix, I was hoping that there was someone that already invented the wheel.
I have had several gold wings and would rather fix the k-bike :)

Is anyone running a Remus pipe ?
 

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Backfire

My '99 LT did the same thing that you described for the first couple of years that I drove it (this is my 5th summer with it). What cured it for me, was when I replaced my throttle cables I sychonized my throttle bodies. Now for the last 15,000 miles it doesn't pop through the muffler like it did before. I can run the revs way up in second and engine brake all the way to idle and it is very smooth.

Give it a whirl!!!
 

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The bike I'm buying tomorrow has a remus and has a pop as well. If there is a solution I'd be interested. The pop is sometimes called an afterburn from what I hear.
 

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Ah, the infamous decel popping. I had it on my 2000 as well after Remus and Rhinewest chip install. What cured it for me was 2-fold.

First, the seal between the Remus mid section and can sucks. The compression slot at the clamp is a source for O2 to scavenge in and allow for unburned fuel to "afterburn" in there. Fix? Use some adhesive-backed 2" wide aluminum tape and wrap it around the mid-pipe section several times. This gives the clamp on the can something to bite into and give a good seal. Smear some Hi-Temp copper RTV on there for good measure if you want.

Second, do the 1.25" OD pipe extension modification.
http://www.bmwlt.com/forums/showthread.php?t=939

This tones the beast down dramatically, but also increases backpressure a little bit to keep the O2 from being sucked in. There was no noticable reduction in power or mileage for me.

I can wind the thing to redline through the gears, snap the throttle shut, and nary a burp. Hope it works for you all.
 

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Sofitel505 said:
Ah, the infamous decel popping. I had it on my 2000 as well after Remus and Rhinewest chip install. What cured it for me was 2-fold.

First, the seal between the Remus mid section and can sucks. The compression slot at the clamp is a source for O2 to scavenge in and allow for unburned fuel to "afterburn" in there. Fix? Use some adhesive-backed 2" wide aluminum tape and wrap it around the mid-pipe section several times. This gives the clamp on the can something to bite into and give a good seal. Smear some Hi-Temp copper RTV on there for good measure if you want.

Second, do the 1.25" OD pipe extension modification.
http://www.bmwlt.com/forums/showthread.php?t=939

This tones the beast down dramatically, but also increases backpressure a little bit to keep the O2 from being sucked in. There was no noticable reduction in power or mileage for me.

I can wind the thing to redline through the gears, snap the throttle shut, and nary a burp. Hope it works for you all.
I'll give it a shot next week and report back.
Thanks
 

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Discussion Starter #10
I did refit the Remus seal .....not with alum tape but I have some and may give a shot. I really like the throttle body synch idea. that would explain why it is not "every" LT that does it. I have a set of mercury sticks but I'm thinking that they are not going to be used since you gotta disassemble the bike to get to the throttle bodies. I will pull out my maintenance CD and see if they have that listed.....

Ya know the first time I took the plastic off my LT I thought it was a pain.....I can have this stuff off in no time now :bmw:
 

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Mine pops like this if I so a hard decel. What fuse do you pull to do that reset?

jzeiler said:
Sounds like you have done a lot already but I have to ask - Have you reset the Motronic and then reestablished the TPS setting for full open and full closed?


After the reset (pull fuse) turn on key - no start- throttle full open then closed twice then turn off key. Now start normally.
 
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