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2004 R1150RT rumbling, stumblin, bumblin on acceleration....


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2004 R1150RT, 12k miles. Just got it a few weeks ago with 10k or so on it at which time it ran perfectly. Remus exhaust, no cat, no charcoal canister, otherwise stock engine.


In the last couple thousand miles it developed a rough idle (a couple of stalls at stoplights even), followed by stumbling on acceleration under load (5th gear, 4000 RPM-- or part throttle in 6th, or 2-up uphill grade moderate acceleration in any gear over 2nd). Top end seems a little flat as well but could be mental. I seem to notice more popping on deceleration / engine braking than I used to but this could be mental. No BOOM, just burble burble pop pop burble burble.


I just changed the air filter, all 4 plugs, oil & filter. Valves were just adjusted, throttle bodies synced with twinmax. This solved the rough idle and seems to have made the stumble a wee bit better. The valves were a bit tight and the throttle bodies a little off, but we're talking minor stuff here- nothing was WAY off.


The plugs I removed looked good - all of them light gray/ tan - no deposits, no black crud.


I'm thinking at this point -in order:


1) Stick coils? If the local dealer has some I'm going to try this because I don't have to take the damn tupperware off to do it. Would the plugs show it if the coils were bad or?


2) Injectors? How do I check the spray pattern and if bad how do I clean them? I know I've seen how to do this but I can't find it now. Something about power to a couple of pins and the injector should spray, and some pins you have to power to shoot cleaner through it?


3) TPS? Seems odd on such a relatively new bike and it ran fine 2000 miles ago.... I have the procedure for doing this but I don't want to screw up something that might be fine.



You folks got any other ideas?

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Sounds to me like you a lugging the motor down, and your getting carbon built up on the pistons. Is this your first BMW R bike? I've only had mine two years, and it was my first (previously I rode all Japanese inline 4's). These bike HATE HATE HATE to run under 4k RPM. Especially if you are riding 2-up and going up a hill. It took a little while for me to get used to it, but now I love it.


You can cruise along in high gear at a moderate rate of speed, but if you give it a bunch of gas it most likely will just bog down, hesitate like crazy, then eventually accelerate out of it. Intsead, if you downshift to say 3rd or 4th and get on it (when the RPMS are up between 4500-7000) thats when these bike take off.


I lugged mine like crazy for the first few months I had it, and it progressivly started running worse and worse. I got some friendly advice from a fellow board member here to go beat the snot out of it for a good 100 miles and it all cleared right back up. Now I just ride it like that all the time grin.gif.


You can still use your higher gears, but just don't rely on them to acceleration for things like passing on the highway.......thats what the middle gears are for. My '00 only has 5 gears and I know yours has 6, but for reference.........the only time I use 5th is when I'm either cruising on the highway going 70+ or when I'm realxing on a backroad and enjoying the scenery. The rest of the time I'm in 3rd or 4th keeping the motor up in the sweet spot (4-7K)

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Mine is totally stock I need to get it out on the road and open it up for a while on occasion or it seems to get a bit sluggish.

An hour or so at a buck ten seems to do the trick. I've been told I could blow it out in a lower gear but my bike doesn't like it as much.


They're made to run they get lazy if you just walk it around everywhere.


Just my 1-1/2 cents worth smirk.gif

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2004 R1150RT ...

3) TPS?

Hopefully somebody will correct me if I'm wrong, but I think there's nothing to adjust on the 1150's TPS, unlike the 1100.

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This isn't my first R bike, I know you have to treat them mean to keep them running their happiest, and I never had a problem with my 1100 doing this, so I think that's the least likely problem.


This doesn't feel like a fuel bog, it feels like intermittent spark. It also didn't do it when I got it, so something changed. One of the things I was really impressed with about the 1150 dual spark engine is that if you rolled on throttle from relatively low RPM it just pulled, whereas my 1100 would bog.


Gonna try stick coils...

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what are stick coils?


The primary plug coils go in the plug hole in the valve cover and are long and cylindrical like a stick, hence stick coils. Apparently they are known for going south.





And I'm back from the shop and a ride - it was the stick coils. Lousy pieces of junk these damn Beemers are, they actually break parts every once in a while I can't believe it.


Anybody know how to test these to see which one is bad (or if both are bad)? I'm hoping one that I pulled is good and I will keep it for a spare.


I did the old "pull one secondary and see if it dies" thing the other day, and it kept running.


It's like the bad one only acts up when it's hot or something, or it's only under more load (higher RPM than idle and more fuel to ignite?) I figure I could heat them both up in the oven to operating temp (which feels like about 110* F - hot to the touch but you can hold it on the back of your hand w/o getting burnt is what I've been taught - seems about right - like a hot tub that's a little on the hot side) and then check them with a DMM - thing is I don't know what to check...


I'll scour the manuals I have but I'm betting they say "plug into diagnostic computer, do what it says"

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God I hate being right ALL THE TIME. From the BMW manual:


61 00 009 Checking ignition coil resistance

• Test with BMW MoDiTeC.



Yah, thanks a bunch you kraut bastards.


Anybody got another manual they feel like checking for me? I'd appreciate it.

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Haynes, 1993-2004 R bike manual, p. 445:


Ignition coil resistance for dual-plug ignition:


Primary spark plugs with direct ignition coil

primary 0.87 ohm

secondary not measurable


Secondary spark plugs with traditional ignition coil

primary 0.50 ohm

secondary 7500 ohn

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Ahh, I knew somebody else who knows black ones are fastest would help me out.


Thank you, that is exactly what I needed.

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  • 1 month later...

Somebody pointed out to me elsewhere that the check procedure posted doesn't work for stick coils, and indeed it does not - I finally got around to checking them last week to see which one would be a good spare to take on a trip...

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