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Rough idle - engine miss - Cause?


daveinatlanta

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daveinatlanta

I just completed basic maintenance - replaced all oils, the 4 plugs (gapped them to about .8mm) the gas filter and the air filter on a 27k miles 04 RT.

Before I embarked upon this, the engine was running fine at all speeds although the idle was about 1000 rpm.

 

Today - I took the bike for its first post-'tune-up' ride. It was a 60 mile ride, most of it at 50-60 mph. Now I have idle problems. Symptoms - and all of these were present when I first started the bike this morning.

 

1. Idle about 1000 rpm. Same as before.

2. It is a rough idle - engine misses. Not a consistent pattern though. This is not the same as before.

3. When in neutral at a stop, with a slight increase in the throttle, the engine still misses - even up to about 2000 rpm

4. But the engine runs ok when under acceleration or at cruising speeds.

5. It is just when starting out from a dead stop that I notice the miss the most. And it is annoying - with the vibration and the general feeling that all is not well.

 

I'm thinking it is a fuel problem because the miss goes away when I'm accelerating or cruising.

 

One thing I did not do - I had to disconnect the battery when I removed the tank and to wire up a Gerbings harness. Then I connected the battery, replaced the tank on and started the engine to make sure I had the fuel connections right. I forgot to do the Motronics reset before I started the engine.....

frown.giffrown.gif

 

I proceeded to put the plastic back on. THEN I remembered the Motronics reset that I skipped. I did not want to undo the plastic and partially remove the tank just to disconnect the negative battery cable again - to erase the Motronics so that I could reset it.

 

So, I just removed the fuse (#5) feeding the Motronics, assuming that the temporary absence of the +12V feed to the Motronics would have the same effect as removing the negative battery cable. Then I put the fuse back in, turned on the key, opened the throttle completely several times to reset the Motronics.

 

This Motronics issue may or may not have anything to do with the engine miss - but that's the only relevant fuel related thing I can think of. (The filter can't be an issue because the engine runs fine at cruising speed.) And I'm pretty sure I connected the vent hoses properly.

 

So - the only other thing I can think of -- the plugs. I guess I can check the gap again - but it just does not seem like an ignition problem.

 

Suggestions? (Other than take it the dealer? Already have an appt - in several weeks!!)

 

Thx

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Did you sync the throttle bodies? Have you checked out the area that the throttle cable connects up with the wheel crank at the throttle bodies? It's very easy to knock the cable off the crank while dealing with the tank and have cable issues there that exhibit similar symptoms.

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daveinatlanta

No - I didn't sync the TBs as thought one needed a special tool or meter for that. I don't think I did anything to the cables because I was not working in that area and I don't think removing/replacing the tank hit the cables. But anything is possible I guess.

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2. It is a rough idle - engine misses. Not a consistent pattern though.

 

Had similar issues once. Re-evaluated the work I had done then.....

PUT the old plugs back in. Ran perfect. Didn't change them out for another 6000 miles.

The NEXT new plugs were ok.

 

Did you gage the plugs with a wire?

Some plugs react maliciously to being "gapped". smirk.gif

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daveinatlanta

Did you gage the plugs with a wire?

Some plugs react maliciously to being "gapped". smirk.gif

Yes - I did gap the new plugs with a cheap $5 NAPA WIRE gage. The one that is round - about the size of the old half dollar. And I gotta tell you - I had problems getting one of the 4 bending tools into the lower plugs which are smaller than the primary/horizontal plugs. However, I did save the old plugs and thought I'd put them back in - just to see if it made a difference. I did not measure the gap on them but I thought the gap was larger than the .8mm that the manual specifies.

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I was going to ask if you remembered to replace the vent hoses/caps on the underside of the Throttle Bodies, but then you said you didn't do a synch.

 

I was going to suggest you look at the ferrules where the throttle cables sit in the adjusters on top of the bellcranks on the TB's to make sure they're all the way down, but then you said you didn't do a synch.

 

I was going to see if you made sure you didn't slosh raw gas up into the top of the vent on the tank when you did your filter where it could dissolve the charcoal in the cannister and plug the return vent line. Do you still have the cannnister or have you done the cannisterectomy already? Does your gas tank make a sucking sound when you open it after a short ride?

 

The other suggestion is to make sure your spark plug wire caps are snapped on all the way onto the primaries (sometimes the "click" is hard to hear/feel). I assume you also removed, inspected and replaced the secondaries with the proper BMW spec plug? How did the original secondaries look? Were they oil fouled?

 

Did you remove and clean the LBBS's and the port they screw into with some TB cleaner? Are the o-rings on the LBBS's still in good shape?

 

You really need to do a TB synch to know what's going on at idle. You can do a search here for "+homemade +manometer" and find specs for one that will cost <$20.00 and <20 minutes to put together. I would also make sure the clamps on the intake tubes and TB's are tight.

 

Check the above and let us know what the synch says and we should have better info to make a diagnosis. Good luck. thumbsup.gif

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It's very easy to pull back on a throttle cable when you are moving the tank. You moved the tank when you changed the filter. This unseats the throttle cable a little so it is not seating properly at the throttle body. I did this myself a few months ago and solved the problem with the help of this board.

So, remove the tupperware and check that the cables are seated.

Good luck! smile.gif

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daveinatlanta

I was going to see if you made sure you didn't slosh raw gas up into the top of the vent on the tank when you did your filter where it could dissolve the charcoal in the cannister and plug the return vent line.

 

assume you also removed, inspected and replaced the secondaries with the proper BMW spec plug? How did the original secondaries look? Were they oil fouled?

 

Did you remove and clean the LBBS's and the port they screw into with some TB cleaner? Are the o-rings on the LBBS's still in good shape?

 

You really need to do a TB synch to know what's going on at idle. You can do a search here for "+homemade +manometer" and find specs for one that will cost <$20.00 and <20 minutes to put together. I would also make sure the clamps on the intake tubes and TB's are tight.

I had 'most', not all, of the gas out of the tank when I removed the filter - but it sat, essentially upside down, on the filler side, all night - because I could not figure out a good way to remove the original crimp clamps until the next morning. I don't know about the cannister - or where it is in the tank. I saw some sort of white tube thingy inside one side of the tank when I was having 'fun' getting the fuel assembly out and back in. Maybe I did dissolve the charcoal and that is the problem...! I do have a cannister above the rear wheel on the right side however - a California Emissions thing I assume. I'll check for the sucking sound tomorrow.

 

I did remove and replace all plugs including the secondaries. The secondaries were the originals, I think, and they were oily and wet. (Hopefully a carryover from the bike's first 10k miles.) But, when I removed them, I had only run the bike on its center stand, in 2nd gear, until it got to 5 bars (to make the oil draining easier) and somebody here suggested that not putting it under a true load may have contributed to a wet look. I'll pull them tomorrow and see how they look. When I installed the primaries, I did get a positive feeling or sound when I snapped the coils back on.

 

I don't know what the "LBBs" are so I don't think I did anything with them.

 

Guess I need to remove the plastic (again..) and see about the cables. If I can't fix it, I'll just ride it naked to the BMW dealer.

 

I think I've found the homemade manometer link and may try it.

 

Thanks to all you Beemer experts for your suggestions.

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So, remove the tupperware and check that the cables are seated.
Yup. Re-check that, and recheck the connections to the lower plugs primary coils.
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I believe all US bikes have the cannister and it is the black can under the rear sub-frame. "Hey, Ken! What's that . . . OVER THERE!!" smile.gifconfused.gifcrazy.giffrown.gif

 

(The directions for a cannisterectomy are here grin.gif )

 

It sounds like your plugs are good. You don't need the secondaries for smooth running/idling and if you checked for a good spark and positive connection (short of a spark timing issue) you should be good there.

 

I don't know what the "LBBs" are so I don't think I did anything with them.

There used to be good definitions of these terms in the M/C FAQ, though it's been awhile since I read the outdated parts of that page. The Large Brass Bypass Screws are on each TB on your bike and regulate the small amount of air that bypasses the throttle plate which at idle is in almost fully closed position. They get sooted up and can affect idle speed, though unless someone really messed up their adjustment they shouldn't be causing what you're experiencing. These are NOT to be confused with the throttle stop screws (a tab on the bellcrank comes to rest against them) which have paint on them and should not be touched. You should remove the LBBS's, clean them, make sure the oring is in good condition, then turn them all the way in (gently) and then 1.5 full turns back out. This is a good place to start your idle synch and if there is no other problem should bring the idle to around 1050 +/-50 RPM.

 

RightSpin's link to his excellent manometer is here.

 

If you ride your bike naked to the dealer, be careful to tie off the speed nuts on the subframe (zip-ties, twist-ties, string, etc.) or you'll wind up with a few extra screws when you go to put everything back together and floppy tupperware. DAMHIK!! dopeslap.gif

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It's very easy to pull back on a throttle cable when you are moving the tank. You moved the tank when you changed the filter. This unseats the throttle cable a little so it is not seating properly at the throttle body. I did this myself a few months ago and solved the problem with the help of this board.

So, remove the tupperware and check that the cables are seated.

Good luck! smile.gif

 

What he was talking about (see picture below). Follow the throttle cable from near the right corner of the picture down behind the fuel injector electrical connector to where you see the cable end seating into a shiny metal shoe (i.e. thumb screw) and retaining nut, threaded into a shiny metal bracket. Below the shoe you can see the actual bare throttle cable wire (unsheathed). That black cable gets "hitched", or hung upward above the metal shoe, rather than sitting down into it, throwing that throttle body out of "sync" with the other side. Lift and drop that cable end down into the shoe, and the problem is solved.

 

I think I'll provide a pix of it hung-up for the next 200 guys who discuss this problem, after it happens to me again (or again, or ...).

.

throttlebody.JPG

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Hi Dave -

 

I'm in Marietta - not as good a wrench as I hope (and intend) to be, but I do my own valves and TBS and have all the stuff on hand. In-laws are in town till Monday, but if you want to drop over next week, we can take a look.

 

PM me if you don't solve it by then . . . valves and TBS take an hour and a half or so from start to finish - really simple to do. We'd start with TBS and plugs to get the idle right, then valves and re-do TBS to really get it running.

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If you ride your bike naked to the dealer, be careful to tie off the speed nuts...

 

eek.gif

I was wondering how long it would take, but then I thought Gleno wouldn't be reading this. smirk.giflmao.gif
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Jerry Johnston
If you ride your bike naked to the dealer, be careful to tie off the speed nuts on the subframe (zip-ties, twist-ties, string, etc.) or you'll wind up with a few extra screws when you go to put everything back together and floppy tupperware. DAMHIK!! dopeslap.gif

Or put the screws back in them and tighten them down. At least if you lose a screw you'll just have floppy tupperware - no left over screws. grin.gif

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daveinatlanta

Update.

 

I removed the plastic and:

 

1. Checked the throttle cables per the pictures above (thanks much) and the cable adjuster nuts were fine - sitting down flush on the bracket above the pulley crank.

 

2. I looked at the cable where it wrapped around the pulley and it was in the groove and clean. I used lots of compressed air to make sure.

 

3. I removed the big brass LBBs, marking them first before backing them completely out - took about 7 complete turns - the screws were relatively clean. I did clean them off however and the sockets in the TBs as well. The o-rings are in good shape too. When I reinstalled them in their original place, 7 turns down, just for grins, I counted how many additional turns it took to completely close them. One and a half - which is the amount some of you suggested backing them off from their closed position. Therefore the LBBs seem to be set about right.

 

4. I removed all 4 plugs and checked the gaps with a wire gage again. About .8mm. as "Clymers' specifies. I thought I had the old plugs to reinstall but I apparently tossed them. One surprise is that both secondary plugs were black but not wet. Carbon fouling? And they were new only 60 miles ago and the 60 miles was ridden at mostly at 50mph or above. The primary plugs looked good.

 

5. After I ran the engine for about 2 minutes, in neutral, and then shut it down. then, after about 15 seconds, I opened the filler cap and heard a brief whoosh. I assume there is always some vacuum in the tank though but I thought I'd do as Jamie suggested.

 

6. I did not do the TB sync. Yet. Ran out of time. I may try it next week. The beemer's clothes are still off - so I have an open engine to work on if I feel so inclined.

 

7. If I decide to ride it unclothed to the dealer, I'll be sure to tie up the speed nuts. Wouldn't want any low hanging nuts to fall off, get caught in the wheels, or drag on the ground. blush.gif

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Update.

...

 

5. After I ran the engine for about 2 minutes, in neutral, and then shut it down. then, after about 15 seconds, I opened the filler cap and heard a brief whoosh. I assume there is always some vacuum in the tank though but I thought I'd do as Jamie suggested.

 

...

 

You should have NO vacuum in the gas tank, it is supposed to be vented.

 

Something is not right. Check your vent lines to make sure they are not obstructed. This can definitely cause the bike to run funny.

 

Jim cool.gif

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daveinatlanta

You should have NO vacuum in the gas tank, it is supposed to be vented.

 

Something is not right. Check your vent lines to make sure they are not obstructed. This can definitely cause the bike to run funny.

I checked the vent lines and they seem ok. However I just ran the engine with the gas filler cap closed and open. No difference in the miss. Wouldn't that rule out a vent problem?

 

Perhaps I destroyed the charcoal when I had the tank sitting on its' top for about 12 hours..!

 

I'm thinking a visit to the BMW doctor (dealer) is where it will be resolved. It has not had a BMW tune up so maybe this is a good time.

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You should have NO vacuum in the gas tank, it is supposed to be vented.

 

Something is not right. Check your vent lines to make sure they are not obstructed. This can definitely cause the bike to run funny.

I checked the vent lines and they seem ok. However I just ran the engine with the gas filler cap closed and open. No difference in the miss. Wouldn't that rule out a vent problem?

 

Perhaps I destroyed the charcoal when I had the tank sitting on its' top for about 12 hours..!

 

I'm thinking a visit to the BMW doctor (dealer) is where it will be resolved. It has not had a BMW tune up so maybe this is a good time.

 

Not necessarily. If your vacuum line is clogged because the canister is messed up, it could still be causing an issue by sucking excess fuel into the engine in spurts as the vacuum builds up, the bleeds off when the canister releases some excess fuel.

 

I had this on my R1100RS, and never really figured it out. But along the way I removed the canister because it was rusting out. I forgot about it for a long time, then one day realized it no longer had a strange idle.

 

SO, try plugging the vent ports on the bottom of your throttle bodies and see what happens?

 

Jim cool.gif

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I just completed basic maintenance - replaced all oils, the 4 plugs (gapped them to about .8mm) the gas filter and the air filter on a 27k miles 04 RT.

Before I embarked upon this, the engine was running fine at all speeds although the idle was about 1000 rpm.

 

Today - I took the bike for its first post-'tune-up' ride. It was a 60 mile ride, most of it at 50-60 mph. Now I have idle problems. Symptoms - and all of these were present when I first started the bike this morning.

 

1. Idle about 1000 rpm. Same as before.

2. It is a rough idle - engine misses. Not a consistent pattern though. This is not the same as before.

3. When in neutral at a stop, with a slight increase in the throttle, the engine still misses - even up to about 2000 rpm

4. But the engine runs ok when under acceleration or at cruising speeds.

5. It is just when starting out from a dead stop that I notice the miss the most. And it is annoying - with the vibration and the general feeling that all is not well.

 

In looking back over this, I'm trying to see what else you could've changed by what you did during the service.

 

1) You could've broken a spark plug wire inside the sheath by bending it sharply

 

2) You could've routed the wires differently and either pinched/broken a wire or routed it along a wire that is causing interferance (it seems like there was a recall on the early twin sparks to fix this simple problem)

 

3) You could have gotten debris past the fuel filter during the change that has caused partial plugging of one or both Fuel Injectors

 

4) You could've gotten the vent lines hooked back up backwards (again, assuming you haven't done your cannisterectomy yet). One vent line has a light row of "X's" down the length--be sure you've got them right.

 

5) You could've washed out some dissolved charcoal into the vent lines causing a plug. There should be NO sound of air movement when you open the gas cap--here we are getting warm!

 

6) You could've accidentally bumped adjusted the Throttle Position Sensor.

 

7) The gas could've been poorly affected by sitting open to the air for a week, or you could've done something to the gas in the tank. But as you said you took a 60 mile ride and you had the fuel level low enough to get the flange off to change the filter so you must've gotten fresh gas by now and the problem persists.

 

Lessseeee . . . air (vacuum leak or pressure/venting problem) . . . spark (weak/missing spark) . . . fuel (bad spray/blocked injector, bad gas) . . . timing (hard to see how you could've messed with this) . . . motronic (bad map, fault set to "limp home" mode).

 

Steps I would take if it were mine:

 

1) I would double check the spark plug wires looking for runs along other wires for any length (either move them further away or cross at more of an angle), condition (boots as well), spray a little contact cleaner into the end of the boot/cap (available in a can at Radio Shack)

 

2) I would make sure the battery is not low on voltage (do you have a charger?)

 

3) I would pull the injectors and check for a uniform, fine spray pattern on both sides. I would double check the fuel line quick disconnects to make sure the return line is fully seated.

 

4) I would have already done a cannisterectomy so this step is moot. ( grin.gif ) But if you're not game for that I would at least pull off the hoses from the bottom of the TB's and then pull off the dust caps on the bleed screws on the front brake calipers and cap the nipples on the bottom of the TB's with them. If the bike now idles fine, this will tell you immediately if the cannister is the problem.

 

5) I would dump all the old gas in the tank into my lawn mower and take the tank to a Chevron and put at least a few gallons of fresh 91-92 octane gas in the tank.

 

6) I would pull the LPB if you haven't already (though I don't know if the twin sparks came with the LPB or if the maps are different). But I would at least pull the #5 fuse again for 10 seconds, re-insert it, turn bike on (kill switch in "run"), open throttle grip WOT/closed 3-4 times, then start it up and see if anything changed.

 

7) If I had made any significant changes, would double check my valve adjust to make sure they were still fine (really at TDC when checked and locknuts all tightened down to 8-10Nm)

 

8) I suppose a compression check would also rule out a coincidental ring/valve problem, but if a piece of sand got into the cylinder (like from not blowing compressed air around the sparkplug hole before removal, etc.), or a dislodged chunk of carbon was wedging a valve open you would find that on rechecking your valve adjustments.

 

9) Although it's likely unrelated to your current problem, I would put a bottle of Techron in the tank with a full tank of known good gas and ride/flog the snot out of it for 220 miles, top it up with fresh gas and change the oil again (aka an Italian Tune-up--don't laugh, it works wonders thumbsup.gif ). If you don't know the history of the bike and it's possible the bike has been puttering around town on short trips with oil puddled in the secondary plugs and soot has been accumulating in the combustion chamber this will let you start with a fresh slate. If the problem is as bad and as sudden as you say this will likely be unrelated and not solve the bigger issue, but if you find the other problem, the Italian Tune-up will make the bike a lot more fun to ride! cool.gif

 

I can't see what else you could've done and without being there I might be missing something obvious, but I'd like to hear the results from the cannister bypass/TB capping first.

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Don_Eilenberger

You won't destroy the charcoal by having the tank sitting upside down since it isn't connected to the charcoal canister when the tank is off the bike.

 

The canister is located in that black lump on the right rear side of the bike.. I believe you mentioned it.

 

As far as the two vent hoses that connect to the tank, it is sorta important these be connected correctly - although I doubt if this is your problem. If they're connected wrong, you will destroy the charcoal canister by filling it with water next time you ride in the rain or wash the bike.

 

I think this is how people destroy the canisters. If not filled with water - they tend to be long-lived devices (think about them on a car - ever heard of someone replacing one?)

 

I found I can check which hoses is which fairly easily.. and then I marked one by using a few tie-wraps on either side of the connector on the right side..

 

One vent is the water/rain vent for the filler cap. If this gets plugged up, and you're in rain for an extended period of time, or even wash the bike and get that area wet, next time you open the cap to fill it, you'll dump water into the tank. DAMHIK.. I just do. This hose goes directly to ground somewhere around the right side footpeg (depending on model, might be located a bit differently.)

 

The other vent is the tank vent - it connects to the charcoal canister through some plumbing and is designed to capture any gasoline fumes when the gasoline heats up, and then the canister slowly feeds them back into the engine via the vacuum ports on the bottom of the throttle bodies after the engine is started (this may be temperature regulated also.. so it doesn't do it with a cold engine.)

 

Anyway - look for the hose that goes directly to the ground. That should be the water drain hose.

 

Remove the hose from the coupling near the seat, so you can reach the end of the hose going to the tank. BLOW in the hose. You should hear the air venting under the cap. There should be little to no resistance to blowing through this line.

 

Then take the other hose - disconnect it - and blow into it. You should feel some resistance to blowing into it that increases as you continue to blow into it. Next let it vent. You will feel air-pressure coming back out the hose at you. The tank got pressurized by you blowing into it and it vents it back out this hose when you stop blowing into it. It will also stink like gasoline. That hose goes to the more complex plumbing (with the purge valve and such) that goes to the charcoal canister. This is the tank-vent line.

 

Once you've figured them out - it's worth marking them somehow so you never have to do it again. Small tie-wraps around the hose - not so tight as to really compress it - works for me. A dab of paint would probably work equally well.

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daveinatlanta

I just spent about 30 minutes writing a LONG response to the suggestions from Jamie and Don. Then when I finished, the site said 'form no longer valid' or something to that effect. So I'll try it again and I'll be much more succinct.

 

 

1) You could've broken a spark plug wire inside the sheath by bending it sharply

 

I wuz pretty careful.

2) You could've routed the wires differently and either pinched/broken a wire or routed it along a wire that is causing interferance (it seems like there was a recall on the early twin sparks to fix this simple problem)

 

Verified that there are no parallel runs.

 

3) You could have gotten debris past the fuel filter during the change that has caused partial plugging of one or both Fuel Injectors

 

Possible. But old filter and hoses were clean.

 

4) You could've gotten the vent lines hooked back up backwards (again, assuming you haven't done your cannisterectomy yet). One vent line has a light row of "X's" down the length--be sure you've got them right.

 

Used Don's suggested blow test above. The hoses were connected properly.

 

5) You could've washed out some dissolved charcoal into the vent lines causing a plug. There should be NO sound of air movement when you open the gas cap--here we are getting warm!

 

The 'blow test' indicated that there are no blockages. Also see the bypass test below.

 

6) You could've accidentally bumped adjusted the Throttle Position Sensor.

 

Didn't touch that little black box.

 

7) The gas could've been poorly affected by sitting open to the air for a week, or you could've done something to the gas in the tank. But as you said you took a 60 mile ride and you had the fuel level low enough to get the flange off to change the filter so you must've gotten fresh gas by now and the problem persists.

 

Tank only open overnight. I sucked out residual with turkey baster. After assembly, I put about 1 gallon back in tank then rode it to gas station to put in fresh 91 octane. The 'old' gas was actually about 1-2 weeks old.

 

 

Steps I would take if it were mine:

 

1) I would double check the spark plug wires looking for runs along other wires for any length (either move them further away or cross at more of an angle), condition (boots as well), spray a little contact cleaner into the end of the boot/cap (available in a can at Radio Shack)

 

Checked and cleaned with contact clnr.

 

2) I would make sure the battery is not low on voltage (do you have a charger?)

 

Measures 12.6 V. I have a new charger for my Suzuki but I have not used it on my BMW which as Mtce Free battery. This is from advice from this site and the service manual.

 

3) I would pull the injectors and check for a uniform, fine spray pattern on both sides. I would double check the fuel line quick disconnects to make sure the return line is fully seated.

 

Connectors seated properly. I did not pull injectors - don't want to screw up something else with my ineptness. And bike runs better at cruising speed.

 

 

4) I would have already done a cannisterectomy so this step is moot. ( grin.gif ) But if you're not game for that I would at least pull off the hoses from the bottom of the TB's and then pull off the dust caps on the bleed screws on the front brake calipers and cap the nipples on the bottom of the TB's with them. If the bike now idles fine, this will tell you immediately if the cannister is the problem.

 

Did this - and no change or improvement.

 

5) I would dump all the old gas in the tank into my lawn mower and take the tank to a Chevron and put at least a few gallons of fresh 91-92 octane gas in the tank.

 

Check. See above.

 

6) I would pull the LPB if you haven't already (though I don't know if the twin sparks came with the LPB or if the maps are different). But I would at least pull the #5 fuse again for 10 seconds, re-insert it, turn bike on (kill switch in "run"), open throttle grip WOT/closed 3-4 times, then start it up and see if anything changed.

 

Didn't pull LPB but did disconnect neg batt terminal again for aobut 30 seconds and open the grip to WOT several times.

 

 

7) If I had made any significant changes, would double check my valve adjust to make sure they were still fine (really at TDC when checked and locknuts all tightened down to 8-10Nm)

 

 

I didn;'t change the valves

 

8) I suppose a compression check would also rule out a coincidental ring/valve problem, but if a piece of sand got into the cylinder (like from not blowing compressed air around the sparkplug hole before removal, etc.), or a dislodged chunk of carbon was wedging a valve open you would find that on rechecking your valve adjustments.

 

I don't have compression tester.

 

9) Although it's likely unrelated to your current problem, I would put a bottle of Techron in the tank with a full tank of known good gas and ride/flog the snot out of it for 220 miles, top it up with fresh gas and change the oil again (aka an Italian Tune-up--don't laugh, it works wonders thumbsup.gif ). If you don't know the history of the bike and it's possible the bike has been puttering around town on short trips with oil puddled in the secondary plugs and soot has been accumulating in the combustion chamber this will let you start with a fresh slate. If the problem is as bad and as sudden as you say this will likely be unrelated and not solve the bigger issue, but if you find the other problem, the Italian Tune-up will make the bike a lot more fun to ride! cool.gif

 

 

Will do Techron after visit to dealer this Sat. I'm still open to suggestions - but I think I'll let the dealer get it right and then maybe I can maintain it. I certainly post what they find.

 

Thanks to ALL FOR YOUR EXPERTISE. Sorry for being so brief in my comments but I wanted to type quickly rather than risk losing all of this again.

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Wow, Dave I can't tell you how often I've been bitten by that "time out" bug but it drives me CRAZY! It took me losing quite a few LONG responses to finally get in the habit of first clicking ctrl-a (select all), ctrl-c (copy) and then in a word or other generic text document ctrl-v (paste) before I click that damned "submit" button.

 

Two problems I see left of what you're tried already. I believe your voltage is too low and that might be causing part of your problem. You can bump up the charge with your charger, but some do say not to leave it on constantly for days/weeks on end if you have a gel battery. I would also double check the alternator belt to make sure it's in good condition and not too loose.

 

Also, you say you didn't check the valves, but that the previous owner didn't do anything but change the oil on this bike for 2X,000 miles?? This could be a critical problem if those valves have never been adjusted! They will normally tighten up with the wear-in process during the first 20-50k miles and if you don't loosen them back to spec clearances they could very likely be causing your running problem but you also run a very high risk of burning a valve and costing yourself a LOT of money! I would NOT do an Italian Tune Up on this bike until you make sure the valves are properly adjusted first!! blush.gif

 

You also may have already burned a valve and that could explain the problem as well, though I hope for your sake it's not too late. You can pick up a very cheap compression tester at Harbor Freight which will narrow that down a bit (to either the rings or the valves).

 

I still think a topped up battery (it should be reading above 14 volts IIRC), a very careful valve adjustment followed by a careful TB synch should solve your problem. These R11XX bikes are really not that complicated.

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Don_Eilenberger
Two problems I see left of what you're tried already. I believe your voltage is too low and that might be causing part of your problem.

12.6V should be just fine actually.. if that's without the engine running. Won't hurt to charge it IF the charger doesn't put out more than 14.4V (gel batteries don't like more than that..)
Also, you say you didn't check the valves, but that the previous owner didn't do anything but change the oil on this bike for 2X,000 miles?? This could be a critical problem if those valves have never been adjusted! They will normally tighten up with the wear-in process during the first 20-50k miles and if you don't loosen them back to spec clearances they could very likely be causing your running problem but you also run a very high risk of burning a valve and costing yourself a LOT of money! I would NOT do an Italian Tune Up on this bike until you make sure the valves are properly adjusted first!! blush.gif

 

You also may have already burned a valve and that could explain the problem as well, though I hope for your sake it's not too late. You can pick up a very cheap compression tester at Harbor Freight which will narrow that down a bit (to either the rings or the valves).

The reason I wouldn't even begin to imagine this being a valve problem is: (1) He didn't touch the valves (2) It started AFTER he changed the plugs.. (3) It appears it was running fine just before he changed the plugs and filter. Be a huge coincidence for a valve to burn at the same time as he did a tuneup.
I still think a topped up battery (it should be reading above 14 volts IIRC), a very careful valve adjustment followed by a careful TB synch should solve your problem. These R11XX bikes are really not that complicated.

I think what's missing in this suggestion is some basics like "what changed with the tuneup" that Dave did? From reading his first message - the bike was running fine until he did the tuneup.

 

He changed the fuel filter and the plugs. He also changed the oil.

 

If we can assume there wasn't a massive overfill of the oil, that pretty much leaves fuel or ignition.

 

Since the bike runs better at high RPM than low RPM, it's not a fuel starvation problem. It could be a partly plugged injector, and that's pretty easy to test for.

 

It also could be a defective spark plug - but I believe Dave tried putting the original ones back in.

 

At this point - it might require some dealer intervention. I can imagine a failure of the primary spark coil (this is a 2-spark, and the primary one is a coil-on-plug design) causing these symptoms. It is apparently not unknown for these coils to give problems (it's VERY well known in the BMW car world - where BMW has recalls out on them for several models..)

 

Troubleshooting in this case may require reading the Motronic memory to see if it stores and fault codes such as a cylinder misfire, or simply swapping out the coils for known good one (Dave - know any 2-spark owners nearby?)

 

The engines will run when one of the coils goes bad.. but they reportedly run rather poorly firing off the secondary plug - the one at the bottom of the cylinder.

 

A careful reading of the plugs by someone who knows how might also reveal where the problem is.. (Dave - have any friends in the area who do their own oilhead tuning?)

 

That's about where I am now.. invoking Eilenberger's Law of Troubleshooting "Look where you last worked.."

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daveinatlanta

Final report ---

 

The root cause was a bad coil on the right side primary plug. The BMW technician pulled off the 12v wire feeding the coil when it was running at idle, and it had limited effect. Apparently at cruising speed (and when the engine was warm), the firing of the secondary plug was sufficient to keep the engine running semi-smooth. But when the engine was cold and at idle, the right cylinder missed.

 

When I started the bike up yesterday morning to drive it to the BMW dealer, I had a REALLY HARD time getting it started. When I finally did, I had to lock the throttle at about 2500 RPM while it ran on the one cylinder - with a LOT of backfiring and smoke -- until it cleared up and got smoother. As I rode it to the dealer, it ran ok - but I had to continually 'goose' it a little at idle to keep the engine running semi-smooth.. Even then the windshield was vibrating.

 

I had BMW adjust the valves and do the TB synch. He made slight adjustments but said they were not far out of adjustment.

 

You had suggested that I check the spark - and that ended up being the culprit.

 

Thanks again.

 

I talked to the tech while he was working on my bike and he gave me several tips - one of which concerned the process I used to warm the bike up before changing the oil.

 

I picked a rainy day to change the oil. Rather than ride the bike to warm the oils, I ran it on the center stand, in gear, until I got 5 bars of temp.

 

Later, after I changed the engine oil, I noticed two things: 1. I put the amount of oil BMW recommends and ended up getting the level almost the top of the sight gage. The tech said always put about 1/3 qt less then the BMW recommends.

 

2. More importantly, after I ran the bike, I wondered why the oil still looked dirty in the sight gage. Here's the key point according to the tech: even though I ran it up to 5 bars on the stand, apparently the oil was not hot enough to open up the thermo in the oil cooler. Then when I finally did ride it for about 60 miles after the oil was changed, the dirty oil in the cooler mixed with the new oil.

 

Needless to say - I got another oil change yesterday.

 

Now I feel much better about the bike and its' condition and am ready to tackle my next project - mounting a Garmin SP GPS. I see there are LOTs of comments here about that.

 

Thx again.

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Thanks Dave! It was nice to read along with the symptoms and the probable causes. Your final wrap up helped me to understand the complete process and added a few extra bits of important information to remember! Nice finale! AndyT

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