Post by: warmas on November 12, 2018, 07:32:23 PM
I have read with interest many posts here re: Kbike repairs.
I have attempted to breathe new life into mine after spotting it for sale along the roadside. Apparently noone before me, as usual, was foolish enough to buy it, but I have been able to make it run, rather well, and all systems on it function, at least for now, properly.
Except, the motor has a randon miss or ignition cut-out noticeable at low rpm-no load power settings. It is quite noticeable at idle or when practising low speed sharp turns: the hesitation makes balance more difficult. The miss is not noticeable under full throttle acceleration. The green neutral light seems to blink in time with the miss. The blink is noticeable at idle. I have studied the wiring diagram for this bike. The power for the neutral light is supplied through fuse #1 from the emergency kill switch, the power to the coils from the emergency kill switch is not fused . I think the miss is electrical in nature; the fuel supply system seems in order. It seems a loose connection, in either the supply or ground circuit to the coils/neutral light could cause the miss.
Separately, the bike does not want to start when cold. A shot of starting fluid to the air intake causes it to start immediately.
Choke control seems to operate, but engine is hard to start cold. Fan for radiator comes on to prevent boiling over, so I suppose coolant temp sensor works OK. I have not tested it with thermometer/ohm meter.
Plugs, injectors, coils, connections to them appear sound: no sparks in the dark, interrupting electric signal to each injector causes a noticeable change in engine rpm.
I disassembled, contact cleanered, and reassembled emergency kill switch, unplugged and contact cleanered and plugged in eletronic fuel injection controller. No change.
Have not tackled ignition switch yet.
I am most interested in any and all ideas, comments, suggestions, etc. you may have.
This bike is considerably peppier than the R100 I have, but does not yet run as well. It rides nicely, although it sounds like it should be powering a hydraulic pump or air conditioner. It is more difficult to troubleshoot.
Thanks in advance.
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Post by: warmas on November 12, 2018, 07:33:47 PM
I have read with interest many posts here re: Kbike repairs.
I have attempted to breathe new life into mine after spotting it for sale along the roadside. Apparently noone before me, as usual, was foolish enough to buy it, but I have been able to make it run, rather well, and all systems on it function, at least for now, properly.
Except, the motor has a randon miss or ignition cut-out noticeable at low rpm-no load power settings. It is quite noticeable at idle or when practising low speed sharp turns: the hesitation makes balance more difficult. The miss is not noticeable under full throttle acceleration. The green neutral light seems to blink in time with the miss. The blink is noticeable at idle. I have studied the wiring diagram for this bike. The power for the neutral light is supplied through fuse #1 from the emergency kill switch, the power to the coils from the emergency kill switch is not fused . I think the miss is electrical in nature; the fuel supply system seems in order. It seems a loose connection, in either the supply or ground circuit to the coils/neutral light could cause the miss.
Separately, the bike does not want to start when cold. A shot of starting fluid to the air intake causes it to start immediately.
Choke control seems to operate, but engine is hard to start cold. Fan for radiator comes on to prevent boiling over, so I suppose coolant temp sensor works OK. I have not tested it with thermometer/ohm meter.
Plugs, injectors, coils, connections to them appear sound: no sparks in the dark, interrupting electric signal to each injector causes a noticeable change in engine rpm.
I disassembled, contact cleanered, and reassembled emergency kill switch, unplugged and contact cleanered and plugged in eletronic fuel injection controller. No change.
Have not tackled ignition switch yet.
I am most interested in any and all ideas, comments, suggestions, etc. you may have.
This bike is considerably peppier than the R100 I have, but does not yet run as well. It rides nicely, although it sounds like it should be powering a hydraulic pump or air conditioner. It is more difficult to troubleshoot.
Thanks in advance.
Post by: warmas on November 12, 2018, 07:39:33 PM
I have no clue how to do that.
Post by: warmas on November 12, 2018, 08:06:49 PM
I give up: what caused his miss?
Post by: Laitch on November 12, 2018, 08:20:02 PM
Thanks for the greeting.Record the sound using your phone. Upload the sound file to the site following the video/audio instructions within the Photo Guidance section in the Welcome to Motobrick section.
I have no clue how to do that.
Post by: warmas on November 12, 2018, 08:23:19 PM
Post by: The Mighty Gryphon on November 12, 2018, 10:24:22 PM
Post by: Laitch on November 13, 2018, 06:49:01 AM
Try that, but keep cleaning all the connectors as Gryph has recommended while deliberations continue.
Post by: warmas on November 13, 2018, 08:33:28 PM
Contact cleanered all connectors beneath tank, and the few in the relay box. Did not unmount relays and contact cleaner them as I had reseated them on their bases early September.
Unplugged coolant temp sensor, resulting fuel mixture then too rich for idle.I think the coolant temp sensor is working properly, as fan also turns on and off. Depressing start button after engine is idling raises rpm 1-200, engine apparently is running lean at idle. Depressing start button at a warmed up 2k rpm raises rpm to 2.8k approx. Such a rise says the engine is running lean.Started right up but does not want to idle until it has warmed up a bit.
Bike runs no different, has very annoying miss/hesitation. Under full throttle acceleration no miss or hesitation is noticeable, probably a richer mixture provided by fuel injection computer.
Pulling the various injector leads one at a time causes, sometimes, varying rpm changes. Disabling injector #2, for example, sometimes results in 1k rpm drop, sometimes 400 rpm drop. I ran the bike on the center stand at 3k rpm in the dark for these injector tests. With all four cylinders on line, all four exhaust pipes were a dull red orange color. I guess each cylinder is making similar power, judging by those colors.
Am going to balance throttle bodies and check injector fuel spray patterns, Have never done either to this bike.
Balancing the carbs on the R100 resulted in much smoother engine operation. The idle mixture for that bike is specified to be leaned to max rpm at idle speed and then enrichened a bit. My K100 appears to be running on the lean side of peak rpm at low power settings, and I have seen lean mixtures cause rough engine operation. I wonder how the fuel mixture can be richened at low power settings for a 1985 K100.
Your thoughts?
Post by: Laitch on November 13, 2018, 08:52:34 PM
Your thoughts?I'd like you to divide your text into paragraphs to make your thoughts easier to read.
After electrical connector clean up, an old bike like yours needs a tuneup. You need to be certain the air filter isn't clogged. You need to replace the fuel filter if you don't know its age. You need to inspect the fuel tank's interior and clean it if it needs it. You need to check the condition of the fuel tank hoses and determine if their connections are tight. You need to clean and tighten the battery's ground connection on the transmission and the connections on its post terminals.
You need to check the valve clearances right now—something you haven't described as part of your program. Maybe you assume that we understand balancing throttle bodies means you'll also check the valve clearances. Don't assume anything. You should also check the throttle body manifolds (bushings) for leaks and the crankcase breather hose for integrity before you perform the balance procedure.
Don't go at this thing piecemeal, hunting here and there for a solution like almost every starstruck new K owner here seems to do. Get it set to spec then see what happens.
Post by: johnny on November 13, 2018, 08:53:48 PM
i gottsa 1 thought... post up a video with audio...
brunhilda baywerische-motosenwerken will be back from her battery of blood transfusions soon...
that should be enough said...
j o
Post by: The Mighty Gryphon on November 13, 2018, 09:24:40 PM
Definitely do a very careful inspection of the bushings above and below the throttle bodies and especially the zigzag hose from the crankcase to the airbox. That hose is famous for cracking and causing air leaks and mixture problems. If you haven't checked it already, I am willing to bet that you will find that it's cracked near the hose clamps.
Last, there are two separate temperature sensors in the engine temperature sensor body. One controls the fan and the other controls the mixture. Just because the fan works, it doesn't mean the mixture signal is correct. Not only could the sensor be whack, but the cable could be worn through and shorting to ground, making the ECU think the engine is warmer than it really is.
Post by: Martin on November 14, 2018, 03:20:18 AM
Regards Martin.
Post by: warmas on November 14, 2018, 08:24:28 AM
Post by: warmas on November 14, 2018, 09:23:44 AM
My inspections cause me to believe the ignition system to be in good order.
I have recently checked the air filter, it is of unknown age but is in good condition.
Fuel filter, pump, tank, wiring, connector, circuit, hoses are, based on my recent inspections, repairs, and replacements, serviceable. I have not measured fuel pressure. I have not inspected the injectors.
Since I forgot yesterday to check, clean and tighten ground connections, those are on my list of today's tasks.
The bushings and clamps connecting plenum to throttle bodies have been inspected by me repeatedly and appear serviceable. I have not tested them for low manifold pressure leaks. Will do soon.
I have not yet checked valve clearances, and don't yet know how to change them. Valves are quiet.
I have checked the plugs several times, but not yet after a strictly idle-rpm run. At my checks they have been white to very light tan. Will do.
The crankcase-to-airbox vent port in airbox is plugged, and vent line is open to atmosphere through a small filter. Port plug bears closer inspection.
Re: coolant temp sensor, my suspicions precisely. My experiment by unplugging it and noting change to very excessively rich mixture and reconnecting it and noting mixture as before and, separately, the fan cycling with temperature are the support for my conclusion as to it's proper operation. I could be wrong. I think the change in resistance with temperature is a signal delivered by the sensor. I have not measured this change with an ohmmeter.
I have, as noted, depressed the starter button at a few different rpms and always noted an increase in rpm, a few hundred at idle to several hundred at above 2k. These changes say to me the mixture is lean. I presume pressing the start button while the engine is running somehow richens the mixture?
Thanks again for the helpful suggestions and ideas. My experience has shown me repeated careful attention to detail usually reveals unfounded assumptions. Murphy's Law.
Post by: The Mighty Gryphon on November 14, 2018, 10:43:10 AM
I can't say why, but I would replace the crankcase breather tube ASAP, mainly for peace of mind.
The temperature sensor has a negative coefficient so the resistance gets lower as the temperature rises. 2500 ohms at room temp, and about 250 ohms when warmed up to normal operating temperature.
Another thing to check is the MAF. They have been known to go bad. I have not had to troubleshoot one, but I am pretty sure there are threads here and at other sites giving info on checking it. The good news is that if you need one, there are a few of them out there. It's possible that the flapper is not closing properly, or the complex resistance element has worn spots and is not making contact with the wiper.
You could also have plugged injectors. Have you run any Techron through the engine? It is a nearly magic elixir for old bricks and clears up a lot of problems caused by stale fuel. A bike that hasn't been run for a while should have at least a couple tanks with Techron run through it.
Quiet valves are scary on these bikes. It means they are probably tight, and can result in burned exhaust valves. Check them ASAP. There are threads here on how to adjust them and the tools you will need. There is a source for reasonably priced shims:
https://www.newmotorcycleparts.net/motor_parts/valve_shims.html
Post by: Laitch on November 14, 2018, 10:44:48 AM
I have not yet checked valve clearances, and don't yet know how to change them. Valves are quiet.To support Gryph's observations, clearly you aren't up to speed when it comes to valve and tuneup knowledge. Just because you don't yet know how to check valve clearances or adjust them doesn't place the procedures in a lower rank on the work list priority. This procedure should be near the top after checking air, electrical, and ignition status. Checking and adjusting valves is essential to tuning up the engine.
Quiet valves can be valves with excessively tight clearances. Tight valves can cause loss of compression, loss of the valve seats, breakage of the valves themselves and severe damage to an engine if any of those broken parts are pounded by the piston. Exhaust valves with tight clearances are quiet but can cause noisy damage more frequently than intake valves. Clearances set to spec are essential for a properly running engine. Symptoms of problems can appear gradually but the cost of ignoring them can be significant. It's ok if valves tick slightly.
Plenty of instruction on checking an setting valve clearances is available on the site.
Post by: warmas on November 14, 2018, 11:20:03 AM
I will compare the CTS resistance readings against those posted.
The crankcase breather tube replacement is one of my many tasks.
The MAF sensor and flapper will require research by me to troubleshoot.
I have burnt some Brand X fuel system cleaner during the few hundred miles I have ridden this bike.
I am aware of the consequences of quiet valves. More research is in order. Thanks for the tip re: valve shims. I have never adjusted a valve with shims.
I am looking forward to the results of this troubleshooting exercise, and grateful of the advice available here.
Post by: The Mighty Gryphon on November 14, 2018, 11:37:04 AM
Post by: warmas on November 14, 2018, 07:39:11 PM
Sprayed starting fluid at intake manifold at cylinder head, caused rapid rise in rpm.
Perhaps I have found what is causing the rough running at low power.
Separately, fuel pump quit, engine died. Verified pump connector plugged in, pump didn't function. Half an hour later, started up as usual. More food for thought.
Administrator wants me to post video with sound, I will have to learn how.
Post by: The Mighty Gryphon on November 15, 2018, 08:36:52 AM
You might have cooked o-rings at the base of the throttle body bushings.
Post by: johnny on November 15, 2018, 08:48:54 AM
does it miss while on the center stand when the engine is running...
j o
Post by: Laitch on November 15, 2018, 08:57:12 AM
Sprayed starting fluid at intake manifold at cylinder head, caused rapid rise in rpm.That's right. You have found one source of rough running. Now carefully spray each manifold bushing to determine if there is more than one defective bushing.
Perhaps I have found what is causing the rough running at low power.
Post by: warmas on November 16, 2018, 09:36:40 AM
Post by: Laitch on November 16, 2018, 01:17:33 PM
Thanks for the clemency, I repent of my sins. Indulgences forthcoming.Thank j o and Acute Toxicity. I'm just a prophet without honor in his own land. :oldguy:
Post by: johnny on November 16, 2018, 01:20:10 PM
i gotts nothing to do with nothing... ac is a whackhoe...
i asked a question and never gotts an answer...
does it miss while on the center stand when the engine is running...
j o
Post by: warmas on November 16, 2018, 06:55:57 PM
https://drive.google.com/open?id=1bf2GFnnruHO4o-yDPXfhBsiN1wR7TF9H
Post by: warmas on November 16, 2018, 07:36:18 PM
Yes it does miss while on the center stand.
During the last two days I have made considerable progress due in no small measure to the aid I have received here.
Yesterday after taking a couple pictures of the bike, which the Management has displayed, I thought I had better disassemble the airbox/filter/airflow meter to verify they were installed correctly. I did'nt see anything wrong with them, but decided to see if I could obtain smooth engine operation by manipulation of the airflow meter while it was disconnected from the plenum. Moving the door in the airflow meter varied the engine operation from so rough it would barely run to smooth as silk, and from lean stumble to flooded rich. It was all good to know, now I know what it takes to allow the engine to operate smoothly. Just before dark I figured I should verify no intake leaks at intake manifold, sure enough a bit of starting fluid sprayed at their bases resulted in rpm increase.
Idle rpm then was around 1k.
You Tube showed how to relax the pressure on the airflow meter door to richen the mixture. Easily enough done, but due, I think, to the intake manifold leaks, I can't get the idle rpm below about 1.2k, unless I lean the mixture via the bypass screw, to drop the rpm, which causes rough engine operation at low power settings, and thus is a vicious circle. I think the cold start cam needs rigged to allow the throttle idle stop to bottom. Nevertheless, I have smoothed up the low power engine operation, which has improved the driveability immensely.
Yesterday I removed the injectors to see how they looked: orings were basically fine, a couple of the yellow nozzle pieces were cracked. I turned the orings upside down, as I had no spares, and reinstalled the injectors. No change noted in engine operation. Day before yesterday I balanced the intake manifold pressures of cylinders #2, 3, and 4 to cylinder #1. No real change in operation noted, but at least I know they are balanced.
Next task is to ensure intake runners are sealed leak-free to the head. Flexible rubber couplings at ends of throttle bodies look good, and seemed not to indicate leaks with starting fluid sprayed on them. I don't really want to remove the throttle body asssembly for fear of altering it's rigging. With the airbox and fuel rail removed there may be access to the socket head screws fastening the intake runners sufficient to determine whether they are loose.
At least now I know my ignition and fuel injection system is functioning. Bike did not want to start the morning. Disconnecting the coolant temp switch a bit allowed it to start right up. The CTS needs further investigation.
Bike has died a couple times for no apparent reason. Dash lights out, headlight on.I thought initially the fuel pump was to blame, but now, after today's random stop, fiddling with the connector for the right hand controls seemed to restore power to the kill switch et.al.
It never ends.
Post by: The Mighty Gryphon on November 16, 2018, 07:52:16 PM
Just before dark I figured I should verify no intake leaks at intake manifold, sure enough a bit of starting fluid sprayed at their bases resulted in rpm increase.
Your throttle body bushings and/or injector o-rings leak. Badly. You need to focus on correcting that before you screw around with anything else. If you mess with anything else right now you will only be making things worse.
Winter is here, so you might as well get it done.
Post by: warmas on November 16, 2018, 08:15:07 PM
Post by: The Mighty Gryphon on November 16, 2018, 10:23:02 PM
The connections most prone to leak are those subject to the greatest pressure differential, which occurs downstream of the throttle plate. My careful application of starting fluid to the base of the intake runners showed an rpm increase, while careful application to other connections seem to indicate no leak. It seems to me if the fasteners for the runners can be tightened, within reason, a bit, and if then the leak disappears, I am good to go for a while. Rubber bits are perishable.
Close, but not exactly correct. On your bike the air is measured at the MAF and the calculation for the mixture is made based on that measurement. Unfortunately, there are a number of places between the MAF and the throttle bodies where unmeasured air can get in and lean out the mixture. Every joint and connection is critical, not just those below the throttle bodies.
You are probably correct in trying to tighten the hold down screws for the lower bushings. I hope you are successful, but fear that either they're cracked, warped, or have bad o-rings under them and that tightening will be a temporary fix at best.
Post by: johnny on November 17, 2018, 08:31:55 AM
does it miss while on the side stand when the engine is running...
j o
Post by: warmas on November 17, 2018, 09:08:02 AM
A leak occurs across a difference in pressure. The difference in atmospheric and intake system pressure is greatest where the intake system pressure is the lowest, downstream of the throttle plate. I am eager to learn how this statement is incorrect.
My experiment proved your point, i.e. that leaks contribute to unmetered intake air which cause rough engine operation.
Altering, as I have, the fuel map, richens the excess air enough to minimize rough operation, but, as you point out, does not solve the leak problem. The leak is only a problem at low power settings, at higher manifold pressures the leak diminishes in value. My bike now is eating a fuel/air mixture through a barn door spring adjusted one click weaker than, presumably, the factory setting. The change in idle quality is quite noticeable.
This bike comes factory-equipped with a powerful cockpit heater, and I plan to ride it all winter long.
Post by: The Mighty Gryphon on November 17, 2018, 09:23:18 AM
Brilliant!!! :clap:
I'l need to add that to my repair techniques. So much easier than screwing around with those throttle bodies!
Post by: Laitch on November 17, 2018, 09:29:38 AM
Yes it did miss some while on the side stand. Curiously, the rpm increased a bit while on the side stand. Gravity opening the air flow meter door a bit?I doubt it. There is a lot of suction drawing air through that critter when the engine is running. A tilt in its angle shouldn't matter.
I wouldn't have tinkered with the air flow meter at all. The leaks in the air intake system need to be stopped. If all other fuel system, ignition system and electrical system elements have been checked then the throttle body balance should be redone according to widely accepted guidelines.
If you plan to ride all winter, be sure you read The Mighty Griphon's instructional posts here on bodywork repair. :giggles
Post by: Laitch on November 17, 2018, 09:42:25 AM
Adjusting the MAF to fix a vacuum leak. Who'd a thunk?Sometimes a guy needs to think outside the powerfully heated cockpit.
Post by: The Mighty Gryphon on November 17, 2018, 09:46:10 AM
Post by: Laitch on November 17, 2018, 10:07:56 AM
If it still breaks up, you could wrap the throttle bodies with some Flex Seal tape. That stuff even fixes boats!!!Now that's what I'm talking about! It comes in different colors, too!
Post by: warmas on November 17, 2018, 11:23:36 AM
Post by: warmas on December 31, 2018, 09:24:54 PM
I do not know why.
I think only the #4 cylinder intake runner has a slight leak.
I have experimented with tuning the three variables in the airflow meter and the ignition timing in my attempt at better gas mileage. The best I have found is a hair leaner on the wiper, one tooth leaner on the spring, and the idle mixture bypass at 3.5 turns open. Ignition advanced a couple mms. Bike starts easily, runs smoothly, plugs are dark tan to light brown.
Mileage varies, best so far just under 40mpg. With tall windshield and full fairing I may not get any better. K100 figures at fuelly.com place me near the median.
Post by: The Mighty Gryphon on December 31, 2018, 10:17:50 PM
What happens when you remove the oil fill plug when the engine is idling?
Post by: warmas on January 01, 2019, 09:10:17 AM
Post by: warmas on January 01, 2019, 09:16:56 AM
Post by: The Mighty Gryphon on January 01, 2019, 09:25:05 AM
The crackcase vent to airbox is in place.
Good. I hadn't seen that you replaced it.
Does removing the filler plug change the idle? Smoother, rougher, no change.
Post by: warmas on January 01, 2019, 09:28:47 AM
Post by: Nine80seven on January 04, 2019, 10:12:07 AM
Post by: warmas on January 04, 2019, 12:43:11 PM
The crankcase vent attaches to the plenum, as distinguished from the airbox. The latter houses the L-Jetronic airflow meter.
I think removal of the crankcase oil filler plug creates a not-metered leak to the plenum. I doubt this leak adds more air to the engine. Rather, this leak provides an alternate path for the intake around, rather than through, the airflow meter, perhaps altering its wiper displacement. My observation of my airflow meter operation as it now is tuned reveals nearly no wiper displacement at idle throttle, and small increases in wiper displacement at idle throttle cause no change in rpm: idle mixture is a hair rich which makes for a smooth idle. Engine runs smoothly enough, it seems, at all rpm, no load or on the road. No hesitation to accelerate.
Accordingly, I expect no change in idle engine operation as a result of removal of crankcase oil filler plug.
I also expect some change in engine operation at cruise rpm, as I think a not-metered leak into the plenum gains in significance at greater airflow rate due to it's alteration of the wiper displacement. Bike on center-stand 4k rpm, observation reveals minute changes in wiper displacement cause noticeable changes in rpm. Bike at this load is tuned to rich edge of lean, lean edge of driveability. I think.
I can very easily be incorrect in my assumptions. Incorrect or not, to learn is the goal.
Another current project is troubleshooting the sole, 4l fuel level light wired to the instrument panel. 7l light is installed in instrument panel, but it's pin #8 is nonexistent in the instrument panel and the harness plug. 7l thermistor in sensor is missing, has been removed, 7l wiring in sensor is intact.
On the bench pin #7 to ground illuminates the 4l light. The sole thermistor in the fuel level sensor seems to function: resistance varies inversely with temperature, at 30F circuit is open, heat lamp on thermistor closes circuit, with continuity to instrument panel harness plug #7.
I have made the 4l light blink while mounted to the bike. Problem may be, now, a simple loose connection.
A useful link: https://drive.google.com/file/d/1J5waA1gcBknatEtHhuTjmSl3Conag5ot/view?usp=sharing
Post by: Laitch on January 04, 2019, 02:47:34 PM
I expect no change in idle engine operation as a result of removal of crankcase oil filler plug.That's simple enough to verify.
If there is no significant intake leakage, I expect the engine to stumble and perhaps stall when the oil filler plug is removed while the engine is running. If there is significant intake leakage, I expect the engine to keep idling.
On November 14 and 17 of 2018, you wrote that careful testing of the manifolds indicated leaks. You did not explain whether leakage was at the manifolds, the manifold bushings, or both. You seemed to indicate manifold #3 was a source of leakage and that you believed that tightening the clamps should correct that condition. You did not followup to explain whether the symptom of leakage had been resolved by means of tightening the clamps. A good strategy would be to disassemble intake assemblies for close inspection of the rubber components to find cracks that would allow air infiltration.
You indicated in a different thread that figures at fuelly.com placed the fuel usage of your moto in the middle of the usage range so things are looking up.
Post by: warmas on January 04, 2019, 10:34:20 PM
I am not yet ready to reseal the intake system. It looks to be quite a job to take it all apart and reassemble with new rubber and clamps.
I suspect your expectation of engine stumble and perhaps stall as a result of oil-filler cap removal would be due to excessively lean mixture?
I now believe the intake leak is small, and exists only at the base of the #4 intake manifold, i.e. at the joint between the intake manifold and the cylinder head. It's significance is yet unknown.
All the intake air, except for a leak after the throttle, passes through the throttle body. Any leak before the throttle body does not alter the volume of air into the engine. A leak before the throttle body is, I think, either metered or notmetered by the airflow meter, according to it's position with respect to the airflow meter.
As regards your expectation of engine operation post-oil filler cap removal, I think such removal will not alter engine operation at all. I think oil-filler cap removal will have no effect on any post-throttle leak. The addition of a notmetered port to the plenum will not, as plenum and ambient pressures are nearly equal, alter engine operation noticeably at idle. At idle, at current tune, small airflow meter wiper displacements do not alter engine operation noticeably. At higher rpm a notmetered plenum leak becomes more significant. At 4k rpm on the center stand minute displacements of airflow meter wiper noticeably alter rpm.
Of course, I can be wrong.
Your thoughts?
Post by: Laitch on January 04, 2019, 10:57:13 PM
As regards your expectation of engine operation post-oil filler cap removal, I think such removal will not alter engine operation at allWhy don't you just go ahead and remove the filler plug while the engine is running? If nothing unexpected happens and the moto performs satisfactorily on the road, all's well.
Your thoughts?
Post by: warmas on January 04, 2019, 11:52:19 PM
I agree if it still runs ok, I will call it good enough.
Post by: Laitch on January 04, 2019, 11:56:46 PM
I am going to do just that, asap.Tomorrow looks good out there—freezing fog followed by partly sunny skies and 50ºF. I might see that sort of thing in May.
Post by: daveson on January 05, 2019, 12:10:49 AM
I'm also interested if the revs change at idle if the filler plug is removed, but I'm thinking if the revs doesn't change then the z hose is possibly leaking.
Is there still a miss, sometime this is an indication that the fuel pressure regulator is leaking fuel. Since the miss disappears at high revs this also indicates the regulator as a cause, i think.
Post by: warmas on January 05, 2019, 07:01:15 AM
Separately, while fiddling with the fuel level light, I managed again to burn up something in the speedo.
It worked fine before all this, now no speedo needle movement, no odometer or trip meter movement, and I think the turn signal self-cancel is now inoperative. I have discovered here pertinent wiring schematics to this bike, but I speak electricity poorly.
The motor runs smoothly at all rpm, with its current tune, which is just a bit leaner than stock air flow meter settings, timing 2mm advanced. I think the fuel pressure regulator is functioning properly.
50f and sun is not uncomfortable to ride behind the K100 tall fairing with the fairing-to-engine plastics missing.
Post by: warmas on January 05, 2019, 07:10:02 AM
https://forums.bmwmoa.org/showthread.php?64487-1994-K75S-Z-Hose-Question
Post by: daveson on January 05, 2019, 07:44:48 AM
Post by: The Mighty Gryphon on January 05, 2019, 08:28:35 AM
I'm thinking we need to get more heat in the house. Should I go for electric heaters or would kerosene be better. Right now I am burning large piles of wood outside the open windows. It seems to help, but the smoke is annoying.
What to do, what to do?
Post by: warmas on January 05, 2019, 12:02:19 PM
Post by: warmas on January 05, 2019, 12:04:58 PM
Post by: natalena on January 05, 2019, 12:12:30 PM
Post by: alabrew on January 05, 2019, 12:16:49 PM
Learn from my "mistake" and remove the throttle bodies first to see what parts you need before you order parts.
The intake runners are all of $5, the part that screws to the head are $50 EACH!
Fortunately, I LOVE Big Red, my '85 K100 Standard, and Hermey's had a 20% off sale.
I would recommend undoing the mess you did with the MAF and bring things back to factory settings for the best results.
Post by: The Mighty Gryphon on January 05, 2019, 12:19:42 PM
Post by: Laitch on January 05, 2019, 12:28:44 PM
50f and sun is not uncomfortable to ride behind the K100 tall fairing with the fairing-to-engine plastics missing.50ºF isn't uncomfortable on a naked K either, if you're geared up correctly and not an invalid.
Have you performed the oil filler plug test or has the ailing speedometer diverted you from that?
Post by: Laitch on January 05, 2019, 12:34:47 PM
I think I'll open more windows to let the smoke out and get another furnace.Why don't you just move the La-Z-Boy, tv trays and the beds outside closer to the fire. This isn't rocket science.
Post by: Nine80seven on January 05, 2019, 12:42:25 PM
No fiddle faddle around, spray this, scrape that, take it apart. But before, read every fricken frakken thing available on the bike. From every period bike mag review to every available repair manual, to every inner web article, every night, read, learn from others' many times mistakes/triumphs. So I knew wth I was doing. Clean everything as you go. Three years later still gonna do some stuff this winter. That's my story FWIW on an early K bike.
Oh, the crankcase Z hose vent. One of first things replaced even though it looked OK. How does it run today? Compared to an airhead? Like a scalded cat.
Post by: Laitch on January 05, 2019, 01:06:15 PM
Separately, while fiddling with the fuel level light, I managed again to burn up something in the speedo.Did you check its fuse?
It worked fine before all this, now no speedo needle movement, no odometer or trip meter movement, and I think the turn signal self-cancel is now inoperative.
Post by: The Mighty Gryphon on January 05, 2019, 01:12:05 PM
Why don't you just move the La-Z-Boy, tv trays and the beds outside closer to the fire. This isn't rocket science.
Then I have to go indoors to get a cold beer. Okay, maybe I could move the beer cooler outdoors. I suppose if the beer got too cold, I could put a small heater in the cooler.
Damn! This is getting pretty complicated.
Post by: Laitch on January 05, 2019, 01:17:18 PM
Damn! This is getting pretty complicated.You think this is complicated? Try removing an oil filler plug.
Post by: The Mighty Gryphon on January 05, 2019, 01:20:28 PM
You think this is complicated? Try removing an oil filler plug.
Absolutely!!! Removing that filler plug one of the annual jobs I hate the most. Without a doubt, the worst part of an oil change!!! I'd rather do a clutch spline lube.
Post by: warmas on January 05, 2019, 02:35:05 PM
Surprising as it may seem, and contrary to my SOP, I have yet to make a mess of the air flow meter. I think I understand its operation. Please correct my misapprehension.
The speedo, long with the rest of the cluster except the clock, is powered from cluster pin #6.
Many thanks for the helpful suggestions.
Post by: The Mighty Gryphon on January 05, 2019, 03:56:09 PM
Beer is supposed to be drunk before it freezes.
That's why I'll need the refrigerator heater.
Post by: warmas on January 05, 2019, 07:28:27 PM
Removal of oil-filler cap at cold 800 rpm idle caused rough engine operation close to stalling. Cold engine fast idle approx. 1500 rpm cap removal induced rough operation.
Engine warmed up after fan turned on exhibited no noticeable difference in operation at various speeds between 1050 rpm and 4k rpm. A flexible imagination might conjure up an infrequent burp. Tach registered no change.
Surprised me that much vapor came out of oil fill at idle. Much less at 4k rpm.
What all this means I do not know, except that the engine runs well enough for me for now.
Post by: warmas on January 05, 2019, 07:32:34 PM
Post by: Laitch on January 05, 2019, 07:52:19 PM
What all this means I do not know . . .:computer-noworky:
Post by: daveson on January 06, 2019, 03:47:28 AM
When you remove the filler cap at idle you have just created a huge air leak in the crankcase, some of which enters the cylinders through the z hose.
My bike runs well, if I remove the filler cap it stumbles, then dies, unless I replace the plug in time.
Post by: The Mighty Gryphon on January 06, 2019, 09:35:12 AM
Your jiggling of the MAF wiper has successfully enriched the idle mixture to keep up with whatever intake leaks you had. As the law of unintended consequences demands, you have also enriched the mixture over the entire range of throttle settings. Do you think that might be reducing the thermal efficiency of the engine? All my bikes get between 45 and 48 mpg.
Post by: natalena on January 06, 2019, 09:48:37 AM
Ancient alien theorists say ... "YES"
Post by: warmas on January 06, 2019, 03:03:47 PM
Rough idle occured with cold engine, as I mentioned.
Warm engine exhibited no noticeable change below 4k rpm in engine operation, as I mentioned.
Why and how, specifically, does the engine stumble upon oil-filler cap removal?
I wonder how one would measure/improve the thermal efficiency of the engine: Egt, cht, mpg, compression test, spark plugs, timing, top overhaul? I have not explored hotter spark, probably unnecessary. Best power is typically a rich mixture, best economy considerably leaner.
I believe, despite your conclusion to the contrary, I have leaned the entire fuel map rather than enriched it. Mpg figures and wiper base points and spring settings and idle bypass settings and color of exhaust pipe and plugs support this belief. The base wiper setting is now leaner than stock, and barely moves and causes no rpm change at idle, by observation. As mentioned, by observation at current tune at speed minute wiper deflection leaner breaks up engine, richer speeds up engine. Pressing the starter button below approx.3.5k rpm results in rpm increase. I have made these observations with the airflow meter uncovered, connected to plenum, harness connected, and engine running on center stand. Please post your more precise test apparatus. I do not have a dynamometer. I had previously restored the airflow meter to its original settings, as you recommend, burned a few tankfuls and observed no increase if not a decrease in mpg. A lean fuel map may not increase mpg.
Thus my experiment.
Further reading: https://itinerant-air-cooled.com//viewtopic.php?f=50&t=7761
Oil cap removal at idle resulted in a vapor leak out of, rather than into, the crankcase, which indicates crankcase pressure higher than ambient, and such removal implies, contrary to my assumptions, less rather than more vapor inhaled into plenum via crankcase vent post-oil filler cap removal. I suspect engine idle stumble post-cap removal is due to wiper position change (intake air change negligeable?). Next time I have bike running and airflow meter on bench consequences of oil-filler cap and/or vent-to-plenum removal to wiper will be obvious.
The purpose of this exercise is to achieve a smooth running bike and the best possible mpg. Bike does have a full fairing, tall windshield. Neither brakes, bearings, nor transmission drag. Cars pass me regularly. The fun/dollar quotient of this machine is already high, your high mpg figures lure me.
Post by: daveson on January 06, 2019, 05:29:36 PM
Post by: daveson on January 06, 2019, 05:41:14 PM
Post by: Laitch on January 06, 2019, 05:51:06 PM
By the way what does it mean if it does or doesn't miss on the centrestand or sidestand.The center stand or side stand positions shouldn't affect the performance of your motos' engines. If one is parked on the side stand the engine might have a tendency to temporarily smoke on startup.
Post by: BearTrap on February 07, 2019, 12:18:35 PM
I think with your year model the 7l warning was not enabled because many people found it more annoying than useful.
I'm also interested if the revs change at idle if the filler plug is removed, but I'm thinking if the revs doesn't change then the z hose is possibly leaking.
Is there still a miss, sometime this is an indication that the fuel pressure regulator is leaking fuel. Since the miss disappears at high revs this also indicates the regulator as a cause, i think.
I've had the vary same problem with my K75. I replaced the fuel pressure regulator with an after market for a VW (with the same pressure rating), along with replacing the vacuum hose for the regulator. Now purrs without a single miss. Run your engine for a minute or two, turn it off and unplug the vacuum line for the regulator #4 throttle and check for leaking fuel (or smell it for fuel). If present, replace the fuel pressure regulator and vacuum line. good luck
Post by: daveson on February 07, 2019, 02:47:33 PM
That's interesting
Which year and model VW has a pressure regulator suitable for our bikes, and which brand did you use?
Post by: BearTrap on February 07, 2019, 06:15:42 PM
Bosch Part # 0 280 160 200
BMW Part # 13 53 1 460 451
VW/Porsche Part # 022 906 035
Jaguar Part # 73177A
Kawasaki # 16162-1002
Post by: daveson on February 07, 2019, 08:11:20 PM