MOTOBRICK.COM
TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Cafe racer on September 16, 2020, 10:59:08 PM
-
First off, is this the right place to post a HELP question...
after about 30 mins of riding, the bike suddenly lost power, I could only rev to about 1000 rmp.
I have checked the fuel pump, I can hear it running. but still only 1000 rmp.
a little history, two days prior after about 1 hours riding I turned off the ignition and the fuel pump continued to run....so I turned back on and started the bike, then turned off again, this time the pump stopped. I am now waiting for a jerry can to arrive so I can drain the tank and remove the pump and check the filter etc...
BUT.... in the meanwhile has anybody got an ideas !!!!!
K100RS 1988 2V
-
When you in there checking the filter, make sure all of the hose fittings are on tight.
How well does it run at idle speed, is it smooth, or rough.
You should also check the TPS wiring plug and operation. You will find instructions in the tech library.
-
I turned off the ignition and the fuel pump continued to run....so I turned back on and started the bike, then turned off again, this time the pump stopped.
This might be a function of temporarily stuck contacts in the fuel pump relay. It might have been a one-off occurrence that won't happen again.
-
What is the battery's resting voltage?
-
What is the battery's resting voltage?
I will pick up my multimeter at the weekend and get back to on that...
-
When you in there checking the filter, make sure all of the hose fittings are on tight.
How well does it run at idle speed, is it smooth, or rough.
You should also check the TPS wiring plug and operation. You will find instructions in the tech library.
Idle is smooth but try to go above 1000 rmp and its rough and wants to stall.
Remind me what the TPS is LOL
Tech library.... now where are my glasses...
-
Get it to stall and then pull the spark plugs. Are they wet or dry?
Regards Martin.
-
Get it to stall and then pull the spark plugs. Are they wet or dry?
Regards Martin.
Hi Martin, certainly not wet...My jerry can and pump should arrive today, then I will drain the tank, pull the pump etc and start some serious investigation
-
Idle is smooth but try to go above 1000 rmp and its rough and wants to stall.
Remind me what the TPS is LOL
Tech library.... now where are my glasses...
In your case "TPS" Throttle Position Switch...
Tells the computer when the throttle is at the closed(idle) position, and when the throttle is equal or greater than 75% open.
You might also check and make sure that the air flow sensor is not stuck in the closed position.
The TPS and AFS both affect how the fuel injection computer controls the injectors/fuel flow.
-
What is the history of this moto, what mileage? Is this a stock 1988 K100RS or cafe'd?
During normal riding 30mins or more does the cooling fan cycle on/off?
After normal riding 30mins or more then loss of power is suspect to a intermittent failure of Hall Effect Sensor.
The test for this is done with a heat gun or a really good hair-dryer. The hall effect sensor assembly lives behind the T shaped cover on the right (facing forwards starboard side of the engine. The cover is removed with allen wrenches.
The test let the engine idle and direct the heat gun at the Hall-effect sensor. If it cuts out when it gets good and warm this is a big clue. Then turn the heat gun to just blowing air and cool it, try restarting. If it restarts, this is the 2nd clue. You may want to do this test a number of times to make certain its the fault.
The hesitation at higher RPMS indicates a weak spark, caused by a partially failed HES. The complete cutout indicates complete ignition failure again, pointing (when combined with the hesitation) to the HES.
Electrical gremlins or instances of intermittent electrical problems can be caused by carbon deposits in the starter motor.
STARTER MOTOR REBUILD
Starter Backspin (http://www.motobrick.com/index.php?topic=5678.0)
Robmack's Starter Motor Cleaning Tutorial (http://www.k100-forum.com/t2342-starter-motor-cleaning-tutorial)
OTHER THINGS TO LOOK AT:
Coils look at them in the dark with the bike idling, just to make sure there isnt a crack in the towers that is causing arc-over.
Ignition wires worth checking the resistance on them. The wires should be 6k Ohms end to end.
The K100 is originally fitted with Bosch X5DC spark plugs (or can be fitted with the NGK D7EA). Both are non resistor spark plugs: The original BMW spark plug cap already integrates a resistance of 5KΩ. Similarly, the connector at the other end of the original ignition cable also includes a resistance of 1KΩ (The total resistance is 6KΩ).
Poor seating of the FI computer connector. More than one intermittent K bike problem like this has been fixed by re-seating the connector on the FI computer. Easy to do, and no cost at all.
Ignition switch or kill switch partial failure. Some people have had problems with deposits on the ignition switch causing intermittent running problems, cleaning it is the cure.
Ignition Switch Cleaning (http://www.motobrick.com/index.php/topic,4909.0.html)
Some links for your K journey
Just bought a 2V (http://www.motobrick.com/index.php/topic,370.0.html)
Just bought a 4V (http://www.motobrick.com/index.php/topic,465.msg960.html#msg960)
Check parts compatibility with BMW MAX Microfiche, BOBS BMW, REAL OEM
https://shop.maxbmw.com/fiche/PartsFiche.aspx
https://shop.maxbmw.com/fiche/PartsSearch.aspx
https://parts.maxbmw.com/BMW___BmwMotorradK.html
https://www.bobsbmw.com/store/microfiche/BrowseSeries.aspx
https://www.realoem.com/bmw/select.do?kind=M&arch=1
https://www.ascycles.com/BMW-Motorcycle-Parts-Fiche
Cross reference parts like Bosch pn#'s, etc.... http://partsplusecat.com/
No spaces in the part number
Parts Vendors
https://www.beemerboneyard.com/
https://www.capitalcycle.com/
https://www.euromotoelectrics.com/
https://www.tills.de/
Headlight relay stuff if you chose to add one
https://www.motobrick.com/index.php?topic=268.0
http://www.motobrick.com/index.php/topic,4962.msg30932.html
http://culayer.com/product/matchbox-headlight-relay/
http://easternbeaver.com/Main/Wiring_Kits/H4_Kits/h4_kits.html Eastern Beaver site is a great reference for electrical connectors,plugs, etc...
http://www.k100-forum.com/
http://www.kforum-tech.com/Tech-page.html
http://www.kforum-tech.com/electrical/EFI/bike-wont-start-EN.htm
http://www.kforum-tech.com/Downloads/electrical/diagrams/interactive_diagrams.htm
http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/k100tshoot/K100.Troubleshoot.Start.2018.pdf
http://kbikeparts.com/index.htm
http://www.kbikeparts.com/classickbikes.com/ckb.tech/ckb.new2k.htm
http://www.kbikeparts.com/classickbikes.com/ckb.tech/ckb.tech.toc.htm
http://www.eilenberger.net/K75S/IgnitionSwitch/
http://www.verrill.com/moto/moto.shtml
this site has a lot of good info and breakdown pictures in the tech and tech resources sections for K1100 alot of the parts are on K75 & K100
http://www.k11og.org/forum/index.php?sid=2df953dde5715fd9001fbe69edec5ad0
https://ibmwr.org/index.php/k-bike-tech-articles/
This site has all kinds of technical specifications on all the BMW models http://www.bmbikes.co.uk/mechanicalpages/kseriesmechanical.htm
http://largiader.com
http://bmwk10075abs1fix.web.fc2.com/index.html Toshi ABS site
Hosa D5S-6 CAIG DeoxIT 5% Spray Contact Cleaner, 5 oz. (https://www.amazon.com/gp/product/B00006LVEU/ref=ppx_yo_dt_b_search_asin_image?ie=UTF8&psc=1)
CAIG Laboratories D100L-25C Contact Cleaner Needle Dispenser (https://www.amazon.com/gp/product/B0000YH6F8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1)
Water Pump
pre-1986-87? original design old style impeller 11411461177
Superseded by 11412325850 design change the shaft with gear Z=32 teeth, shaft- 11411461183
Superseded by 11417676366 same shaft with gear Z=32 teeth
latest design 11517676371 design change shaft with gear Z=19 teeth, shaft- 11411461793
-
What is the battery's resting voltage?
Voltage at rest is 12.37.
-
What is the history of this moto, what mileage? Is this a stock 1988 K100RS or cafe'd?
During normal riding 30mins or more does the cooling fan cycle on/off?
After normal riding 30mins or more then loss of power is suspect to a intermittent failure of Hall Effect Sensor.
The test for this is done with a heat gun or a really good hair-dryer. The hall effect sensor assembly lives behind the T shaped cover on the right (facing forwards starboard side of the engine. The cover is removed with allen wrenches.
The test let the engine idle and direct the heat gun at the Hall-effect sensor. If it cuts out when it gets good and warm this is a big clue. Then turn the heat gun to just blowing air and cool it, try restarting. If it restarts, this is the 2nd clue. You may want to do this test a number of times to make certain its the fault.
The hesitation at higher RPMS indicates a weak spark, caused by a partially failed HES. The complete cutout indicates complete ignition failure again, pointing (when combined with the hesitation) to the HES.
Electrical gremlins or instances of intermittent electrical problems can be caused by carbon deposits in the starter motor.
History
Bike is a standard 1988 K100RS 2 valve, no modifications
I purchased the bike as a non runner, but a used alternator fixed that problem (not charging)
My first ride just a few K's was oK
Second ride about 1 hour no problems, but at the end of the ride the fuel pump continued to run when ignition turn off (suspect fuel pump relay) this fixed itself when the bike was started again and then turned off at the key.
Third ride (and last) after about 40 minutes (hot day about 32°C, temperature gauge was just above the middle) I was in 5th doing about 60kph when I lost power, I pulled over and only had idle, would not rev above 1000 rmp. even after cooling down for 2 hours, still only tickover. the following day (bike was picked up by recover truck) still only tickover.
So far
Fuel pump removed, it pumping fine submerged in a bucket of fuel.
wires in tank have 12v when the starter is pressed.
battery voltage at rest 12.37 (18Ah battery new)
inline fuel filter in tank OK
Hall Effect Sensor checked by pointing heat gun at it with T shaped cover removed, bike was at idle and nothing happened...
-
the latest is...
Fuel pump removed, it's pumping fine submerged in a bucket of fuel.
wires in tank have 12v when the starter is pressed.
battery voltage at rest 12.37 (18Ah battery new)
inline fuel filter in tank OK
Hall Effect Sensor checked by pointing heat gun at it with T shaped cover removed, bike was at idle and nothing happened...
Its running again....and reving as normal
CRC 2-26 to ECU plug and connection to tank for pump and sender
BUT...
when I turned off the ignition the fuel pump continued to run.
So I pulled the relay, popped off its cover and gave it a drink od CRC 2-26
so far all is well, in the next few days I will ride it in a loop around my home, so that it;s in pushing distance if it plays up again. I will update this post in the next few days.
BIG thanks to everyone that helped so far...
-
Voltage at rest is 12.37.
Should be at least 12.7V.
Your battery is deceased...R.I.P.
-
Like the Mighty Gryphon suggests, you need to determine the condition of the moto's battery. If the moto is infrequently ridden and not consistently maintained with a suitable battery charger, it will fail regardless of how new it is.
For cleaning electrical contacts DeoxIT D5 (https://caig.com/deoxit-d-series/) is an effective cleaner. Many riders here use it for cleaning and maintenance of electrical connections. It can be ordered online or can sometimes be found where electronic musical instruments and amps are sold.
-
Should be at least 12.7V.
Your battery is deceased...R.I.P.
I am not off to the cemetery just yet
12.73 or better 100 percent. Go ride.
12.62 90 percent. Charge it, then go ride.
12.50 80 percent. Charge it, then go ride.
12.32 70 percent. Charge it, then go ride.
12.20 60 percent. Charge it, then go ride.
12.06 50 percent. Charge it, then go ride.
-
12.37v resting voltage after a ride tells me that the charging system or the battery has a problem. Normally it should be 12.8v.
You mentioned earlier that you replaced the alternator. Alternators don't normally fail unless they are exposed to some sort of external problem. What you are describing sounds to me like the alternator is not charging the battery while you are riding.
What is the voltage on the positive battery terminal when the engine is running and the battery light is not lit on the instrument cluster? It should be around 13.2v or more.
-
12.37v resting voltage after a ride tells me that the charging system or the battery has a problem. Normally it should be 12.8v.
You mentioned earlier that you replaced the alternator. Alternators don't normally fail unless they are exposed to some sort of external problem. What you are describing sounds to me like the alternator is not charging the battery while you are riding.
What is the voltage on the positive battery terminal when the engine is running and the battery light is not lit on the instrument cluster? It should be around 13.2v or more.
I misunderstood, the voltage I took at rest wasn't after a ride, the battery had been used trying to start the bike.
when I purchased the bike (blind from a trade auction) it had a new battery and new regulator/rectifier but it still failed to charge the battery, hence why it was in a trade auction as a non runner.
I replaced the alternator and it was then charging the battery, I don't recall the exact voltage but something like 13v plus....
sorry for confusion
-
I have charged the battery off the bike its now fully charged at 13.66v
-
Is the moto continuing to run appropriately after the relayotomy?
-
Is the moto continuing to run appropriately after the relayotomy?
Its running OK ish, previous owner had replaced the pump with a very professional anti vibration damper and gauze filter. the pump is unknown brand and type. on the test run is was vibrating so much against the tank I could not here the engine. So I have ordered a full kit, to replace the professional job.
Is it normal to have a lot of fuel always returning to the tank? due to the heat of the fuel rail, the returning fuel is warm, maybe too warm !!!
[ Invalid Attachment ]
I have ordered this kit
[ Invalid Attachment ]
So now its a waiting game.....
in the meanwhile I will flush out the tank, and rebuild the front brake calipers, just for FUN..
-
Is it normal to have a lot of fuel always returning to the tank? due to the heat of the fuel rail, the returning fuel is warm, maybe too warm !!!
Yes it is normal. And yes the returning fuel is warm. It can even boil on hot days in stop&go traffic. Tank gets really warm to the touch and you can consider a fuel cooler (read about them here on this site).
-
The above fuel pump kit has arrived, so it looks good quality, the vibration damper fits well and the filter a snug fit on the damper. so next job is to clean out the tank and fit it.
-
Fuel pump installation went kind of ok, took awhile to realise that the securing ring tabs are different widths, and working blind, I had it the wrong way.... so a quick rotate 180° and it popped in with ease.
Started up and runs great, now waiting for inspection....
-
icon_cheers
-
Just a quick update, the K is now running really well, I prefer it to my last R1150R, I have ordered a new complete rear shock, that will make the ride better, so now need to firm up the front brake lever pressure its soft and spongy but pulls the bike up. and have a look why its overheating, not to bad this time of year, but I know next summer it will be a problem in Tokyo stop start traffic in 35deg C plus.
-
congratulations on your fix.
what rear shock brand have you ordered and from where?
just out if interest
-
Good to hear you have the bike running well!
Next, I would do a complete cooling system flush with a couple of distilled water internal rinses. It's a lot of work, but when I had cooling issues they were caused by a lot of bugs and debris in the fins. Removing the radiator and doing an overnight soak in white distilled vinegar cleaned out an impressive amount of dirt and the engine never got overheated again.
Spongy brakes can often be the result of a bubble or two in the hose that doesn't want to come out. I and others have had success with tying the brake lever back to the grip with the wheel turned to the left. Leave it over night with the cover off the reservoir and the bubbles should come out.
Another cause of sponginess is the old rubber brake lines that are going soft with age. I replace the lines with braided stainless lines as part of every bike's restoration.
As long as you are doing a lot of work on the bike, one of your countrymen has a company named Eastern Beaver that makes very nice headlight relay harnesses for motorcycles.