Strange idle behavior on manometer

[Fossil Fred]

Hi All,

I am trying to get my 2001 R to run a little smoother. I made a Manometer following Cyclerob's instructions - thanks Rob for this and so many other things.

The bike has just had a major service and some other work performed by BMW Specialists with a good reputation but not a BMW Dealer.

The strange thing is this: The idle has been set by the workshop at around 1150 rpm. After starting the engine it usually drops back to a little over 1000 rpm and the engine starts to stumble. Regardless of which of the two manometer tubes I connect to the right-side TB, the fluid in that tube gradually rises and does not stop rising until I switch off the ignition. I am not adjusting anything, just standing watching the fluid rise.

As far as I know this is not normal behaviour - or is it?

Also, the bike is rather reluctant (hesitant) to start but always does start and is reasonably quiet at idle unless I blip the throttle when there is a noticeable "clacking" sound coming from the LHS when it returns to idle. The clacking sound does not stop until I switch the engine off (ie subsequent blipping or revving does not cause it to go away). The workshop upgraded the left cam chain tensioner during the work mentioned above.

Any thoughts?

Cheers

Nige

[riceburner]

Sounds like the idle balance isn't quite correct; the right cylinder has a greater vacuum than the left - that's what the manometer is telling you. The manometer shows the difference between the manifold vacuums.

Regarding the 'clacking' - did they fit the newer tensioner body, or put in a new version of the the older part?

[AZBMWRIDER]

When attempting to perform a throttle body, or carb synchronization, the engine must be at operating temperature before ever trying to see what you have, let alone doing any adjustments .

[CycleRob]

Fossil Fred,
Your thanks are appreciated. The fact that some guy in Australia using the internet can immediately benefit from what is posted here (for free) is profound. I did not invent the differential manometer instrument, I just showed how to make one 'on-the-cheap' and placed the 2 tubes touching together to eliminate any parallax judgement error. It also simplified mounting the tubes to the board. I always enjoy how accurate, quick and easy it is to use at TB synch time, plus it is always in absolutely perfect calibration.

Your observant description of the symptoms was more complete than usual and carefully worded . . . but we need even more info.

1--Is the noise is coming from the cylinder head or the TB ?
2--What is the odometer reading on your 13 year old bike, because high mileage usage usually generates TB shaft and bushing wear that creates that clacking sound at idle. You can even see the throttle shaft and cable pulley moving when it is making that noise. This almost normal wear causes the idle speed to be different during your rides, fluctuate while idling and drive you crazy when you try in vain to dial in a perfect TB synch. Riding on dirt roads more than usual also accelerates the wear.

I suspect that 13 riding seasons and high mileage have also taken their toll on the fuel injector nozzles cleanliness (deposits) that now generates a corrupted spray pattern and is responsible for the rough running. The cure is only one of these 3 options:
1-- Replace them ($$$).
2--Remove them and send them out to have them professionally cleaned ($$).
3--Clean them yourself ($) with sequential repeated use of a brand name fuel injector cleaner using a mixture slightly WEAKER than the recommended "1 bottle/20 gallons" recommendation. Measure it carefully with a small measuring cup. The 'more-is-better' train of thought does not apply here because most gasolines already have fuel system cleaner additives in them making the risk of EFI component damage possible.

A good mechanic (if time permits) will always make the easy shots first. If it's your bike and there is time, choice 3 is my advice. Replacing the TB shafts and bushings is for the BMW dealer or a real pro to do it right as it involves precisely resetting the blue painted idle stop screws and the TPS . . . . if you want it to run right.

[Fossil Fred]

Thank you all for your replies. To answer some questions and provide more info:

1. They fitted the ‘update’ timing chain tensioner components
2. I had been on a 40km ride before I started to look at the idle & synch, so the engine was well warmed up.
3. Rob, my hearing isn’t all that good these days (too much loud music on headphones when I was younger), so I couldn’t say with certainty, but the noise seems to be coming from below and inboard of the LH throttle body, behind the plastic cover. I ride with a bunch of other old fogeys on Thursdays, so I will ask some of them to have a listen this Thursday and see what they think.
4. The odometer reading is 102,500 kilometres.
5. The fuel injectors were replaced with (I’m not sure of the correct terminology here) ‘refurbished’ ones during the service a couple of weeks ago. Prior to that I had tried using (carefully measured) injector cleaner without effect.
6. Other stuff that was replaced on the service: Fuel filter, all the throttle cables (including an ‘upgrade’ to the Junction Box) which has made the throttle action much lighter and kind of hair-triggered).
7. Before the service the bike felt sluggish, not at all like the bike I remembered (see point 10). The service achieved something because the performance of the bike has been transformed and once again it pulls like a train, so whatever is wrong, it is not affecting performance.
8. When I owned it first time around it had soft, pulsing vibrations which were quite pleasant. Now it has a harsh buzz through the bars, the seat and the footpegs. This is what I am trying to reduce.
9. This is probably subjective, and may not be relevant but since the service the clutch engagement (if that is the correct term) seems different. I have to release the lever until it is almost at the end of its travel and suddenly it engages. Several times I have almost stalled the bike. Prior to the service it was a more gentle transition from off to on, so to speak. I am finding it difficult to change gear smoothly (but only on this bike. I have two other bikes and my gear changing on those is as smooth as ever, so it doesn’t seem to be rider-related)
10. It may be worth noting that I owned this bike from new in 2001 and traded it in in 2005, buying it back again from the 2nd owner in 2012. In the seven years of the other guy’s ownership it appears from the “service record” he gave me (which included all of my original documentation) that the bike was serviced just once, in 2006. The bike was absolutely filthy, and did not seem to have been washed in all those years. I have spent months cleaning it up, but there is still ground on filth that I cannot remove. If anyone has any suggestions on how to remove baked on grime from the cooling fins I would be most grateful 

Cheers

Nige

[CycleRob]

The TB shaft and bushing wear, especially in light of the 63,690 miles and riding environment that caused the heavy filth layer that was not regularly cleaned off, still would indicate it is the major offender.

I recommend you also perform a compression test: Wide Open Throttle, both injector wire connectors unplugged, crank starter with gauge needle showing 5--7 compression "pump ups". Even better . . . actually the best cylinder integrity test, is known as a "Leak-Down Test". A hand held 2 gauge tester connected to the tested cylinder that is exactly on TDC compression stroke and 105+ psi shop air supply is required. That LDT will reveal what component is not sealing the tester valve's operator adjusted 100 psi cylinder pressure by what is audibly hissing: the airbox inlet (intake valve), exhaust pipe outlet (exhaust valve) or crankcase oil filler opening (piston rings). It will also show the percent leakage on the 2nd gauge. A compression test only tells you there is a compression leakage problem. A LDT tells you what parts are bad and how bad they are.

Another engine idle test to perform would be to "test shot" spray the cylinder/intake manifold gasket junction, TB intake manifold junction and injector/TB housing junctions with carb cleaner spray . . . listening for any idle speed change when they are pulse shot sprayed sequentially around their sealing circumferences.

A manometer column that "continually rises" to me shows an air leak or a crack in the connecting manometer hose, but you say it still happens when the hoses are switched. My politely asked question is; are you sure the SAME colored water column rose when they were switched?

[Sunbeemer]

You might inspect the vacuum hoses attached to the nipples on the bottom of each throttle body for cracks or splits. Mine were cracked right below where they connected to those nipples and caused a vacuum leak.

[Fossil Fred]

Rich,

Thanks for the suggestion. I am assuming that you mean the hoses on the Manometer. If so, I have checked them and they do not appear to have any cracks. Just to be sure tomorrow I will cut a little off each tube and try again to see if the results are the same.

Rob,

Thanks again for your replies.

Regarding your "polite" question. Perhaps my explanation was not sufficiently clear, so I got my lovely wife to supervise while I conducted the test again to make sure I wasn't suffering from a succession of Senior's moments. She has also (enhanced and) proof-read this post to verify it is an accurate account. Here is what happened:

At idle, if I connect the RH tube to the RH TB (and the LH tube to the LH TB) and leave it idling, the fluid in the RH tube will gradually rise. If I connect the LH tube to the RH TB (and the RH tube to LH TB) and leave it idling, the fluid in the LH tube will rise. So, the fluid in the tube attached to the RH TB will rise (which is the behaviour I saw first time around and is what I intended to say in the OP).

Now we did notice something else: With the RH tube attached to the RH TB (and the LH tube to the LH TB), if I hold the throttle at a constant opening (I used 3000rpm), the fluid in the LH tube will rise. If I connect the LH tube to the RH TB (and the RH tube to the LH TB), the fluid in the RH tube will rise. That is, the exact opposite of the behaviour at idle. Also, the rate of rise with the throttle open was much greater than the rate of rise at idle, in the order of three times faster.

I will get some carby cleaner and try the test you suggested and I will investigate having a LDT done.

[Fossil Fred]

Rob,

I'm a goose! I sent the wrong emoticon . I meant to send this one

You would think a man who spent his working life in IT would be better at this stuff.

Nige

[riceburner]

Rich,

Thanks for the suggestion. I am assuming that you mean the hoses on the Manometer. If so, I have checked them and they do not appear to have any cracks. Just to be sure tomorrow I will cut a little off each tube and try again to see if the results are the same.

Rob,

Thanks again for your replies.

Regarding your "polite" question. Perhaps my explanation was not sufficiently clear, so I got my lovely wife to supervise while I conducted the test again to make sure I wasn't suffering from a succession of Senior's moments. She has also (enhanced and) proof-read this post to verify it is an accurate account. Here is what happened:

At idle, if I connect the RH tube to the RH TB (and the LH tube to the LH TB) and leave it idling, the fluid in the RH tube will gradually rise. If I connect the LH tube to the RH TB (and the RH tube to LH TB) and leave it idling, the fluid in the LH tube will rise. So, the fluid in the tube attached to the RH TB will rise (which is the behaviour I saw first time around and is what I intended to say in the OP).

Now we did notice something else: With the RH tube attached to the RH TB (and the LH tube to the LH TB), if I hold the throttle at a constant opening (I used 3000rpm), the fluid in the LH tube will rise. If I connect the LH tube to the RH TB (and the RH tube to the LH TB), the fluid in the RH tube will rise. That is, the exact opposite of the behaviour at idle. Also, the rate of rise with the throttle open was much greater than the rate of rise at idle, in the order of three times faster.

I will get some carby cleaner and try the test you suggested and I will investigate having a LDT done.

Your balance is out slightly in different directions.
At low speed the RH TB is slightly 'advanced'*
At high (engine) speeds the LH TB is slightly 'advanced'*

Balancing the TBs is done in two stages - low speed and high speed.

Low Speed is done by adjusting the BBA screws so that the manifold vacuums are equal.
High Speed is done by adjusting the throttle cable tension so that the manifold vacuums at a given engine speed (3K is generally used) are equal.

Roughly speaking: once the engine is spinning above about 2K the BBA screws don't have much influence on the volume of air in the manifold, that is controlled by the butterfly valve (and the level of fuel being injection by the TPS on the LH TB). To ensure that the engine is balanced at high engine speeds you need to ensure that the butterfly valves are both opening the correct amount - this is done by adjusting the throttle cable knurled nuts at the TB: (ie adjusting the throttle cable tension until they are giving equal vacuum in the manifold).

Hope that helps?




* random term used to indicate differences

[CycleRob]

After reading your post directly above, and in light of what was first said by you, I realized you are not completely aware of the adjustments and what they do. The confuser:

"Regardless of which of the two manometer tubes I connect to the right-side TB, the fluid in that tube gradually rises and does not stop rising until I switch off the ignition. I am not adjusting anything, just standing watching the fluid rise."

The underlined part describes a fluid level that travels upward slowly/steadily, inch by inch, with an ever widening liquid level gap until it topped over the manometer top loop, allowing the engine to eat it all. Is that correct? If you say yes, then ONLY a cracked or loose fitting LEFT TB brass vacuum spigot (pointing straight down from the TB) would cause such a result. Examine only the left TB vacuum spigot tube with a small mirror, reading glasses and a bright light for any wrinkles/bends/cracks in that short pipe or if it is loosely mounted to the TB casting. The tube may have been bent in aggressivily trying to tool remove a stuck on vacuum hose or a tip-over collision with a stationary object and then restraightened.

The adventure continues . . . .

[Fossil Fred]

Rob,

The underlined part describes a fluid level that travels upward slowly/steadily, inch by inch, with an ever widening liquid level gap until it topped over the manometer top loop, allowing the engine to eat it all. Is that correct?

Yes, that is correct. If I had not switched off the engine the fluid would have gone over the top and into the engine. My apologies if my description was inaccurate to begin with. I see where you are coming from regarding the LH spigot, but both myself and wife have examined it as you directed and can see no wrinkles/bends/cracks. It seems to be solidly mounted and looks straight. To our eyes it looks just like the RH spigot. If anything it has a tad more petrol on it/in the rubber boot than the RH side.

Maybe its time to go back to the workshop and get them to have a look at it.

[sweatmark]

Fwiw - This topic reminded me of some old info pertaining to intake leaks and tuning:

http://www.r1150r.net/board/viewtopic.p ... 2f51bc3d86

http://www.r1150r.net/board/viewtopic.p ... 2f51bc3d86

http://www.r1150r.net/board/viewtopic.p ... 2f51bc3d86

http://www.r1150r.net/board/viewtopic.p ... 2f51bc3d86

This is reminder to myself to buy throttle body rebuild parts, plus check the intake tube connections.

[Sunbeemer]

Your manometer symptoms combined with the "clacking" sound at idle would lead one to suspect worn butterfly shaft holes in the throttle bodies. Perhaps you can exactly identify the source of the noise using a screwdriver held against the throttle body and placing your ear against the other end to "telescope" the sound to your ear (as a surgeon's stethoscope does). This can help effectively isolate the source of noise.

If it is apparent the noise comes from the throttle body(ies), they probably should be rebuilt or replaced.

[sstein]

Your balance is out slightly in different directions.
At low speed the RH TB is slightly 'advanced'*
At high (engine) speeds the LH TB is slightly 'advanced'*

Balancing the TBs is done in two stages - low speed and high speed.

Maybe just rebalancing the TBs is the answer to the manometer issue. The tech who worked on the bike maybe just did a poor balancing job. Adjust the idle balance with the BBAs and adjust again at 3000 RPM with the cables. Then see if the problem persists? Does that make sense?