Noise + shutoff when using throttle in neutral

[ffjad]

Hello everyone,


This is my first post on this forum. I'm 24 years old and I live in the Netherlands. I bought my first bmw motorcycle today, a K100 (1985). I'm having a few issues though..


My bike starts fine and idles nicely too. When I try to rev, the bike makes a rattling sound somewhere and shuts off. Turning the throttle really slowly doesn't make the bike shut off till a certain point. The previous owner removed the whole speedo unit (all cables are out) and I'm using a car battery now, because the battery that came with it is dead. I can't find any topics regarding this issue.


Can anyone help me?

[BrickMW]

Hello, and Welcome!


How long will it idle? Indefinitely?
If so I would suspect fuel / fuel delivery...


Fresh fuel, new filter then check injectors, pump, regulator..


Any cracked hoses?


Also, try cranking it with the TPS disconnected, and verify the switch with a meter if you have one.


Lots of good stuff here -->http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/bike-wont-start1.htm

[Laitch]

I can't find any topics regarding this issue.

:hehehe :laughing-on-ground:
Welcome to the party, ffjad! Not running very well is characteristic of old K-bikes that have their wiring looking like misplaced mobs of nightcrawlers. Don't worry. There are several specialists here ready to help you as soon as they come back from wherever they are.

Please post some photos of your bike and an audio file of the noise so we can assess its condition. I notice you have put your bike's model in your profile. Please put its year in there also because there are differences in components sometimes, based on the year the bike was made.

[ffjad]

Car battery is charging atm, can't start the K. When looking for the TPS socket I noticed 2 different loose sockets. See pics below, any clue what those are for?

[BrickMW]

appears to be connections for an auxiliary battery tender.. the "blade" style is stock and would connect to the back of the socket style tender/aux port. Normally mounted in the top section of the coil packs cover.

[The Mighty Gryphon]

The small connector is for a high altitude adjustment.  It consists of a jumper that is connected when the bike is operated at altitudes above 4000ft above sea level.

[Laitch]

It consists of a jumper that is connected when the bike is operated at altitudes above 4000ft above sea level.

http://www.motobrick.com/index.php?topic=370.0

altitude plug.jpg (43.46 kB . 324x409 - viewed 438 times)

[ffjad]

Thanks for the help guys. Are those necessary or can I follow the cables and unplug them somewhere to clean up?

[Inge K.]

Are those necessary?

The power connector can become handy, you allready have the blade connector and bracket, search ISO 4165.

http://www.mopart.de/BMW-Ersatzteile-K100-Steckdose-BMW-K100LT/a48385253_u3834_z386104c8-f80c-4390-9151-178bff4f7cec/


The plug for the high altitude connector is shure not needed where you live (the connector is a part of the
main harness, and indicates that your bike is US import).

[ffjad]

Finally had some time to get some things done on the K. After replacing all filters / oil / spark plugs / battery the K starts right away. The knocking/rattling didn't go away though. I made a recording of the noise.


At idle without choke there is a knocking sound, it seems to come from the timing chain. With choke the idle goes up and the knocking is less hearable. When I turn the throttle a little bit there is a rattling sound coming from the same place (somewhere beneath the timing chain cover). You can hear the rattling at 11, 12 and 14 sec on the recording. What could this be and what's the best fix?

[ffjad]

Extra info:


Among the parts I got with the bike I got a used timing chain, tensioner and 2 gears, could the new ones be installed wrong?

[BrickMW]

Is the original instrument cluster back on the bike? Is the oil pressure warning light lit?


The timing chain tension is controlled by oil pressure, you might have low/no pressure at low revs.?.?


When you changed the oil, how did it look? Sludgy? Thin? Did the oil filter have a paper label, or remnants of one? What kind/weight oil did you put back in it?


It certainly is a cringe inducing knock. I would verify oil pressure ASAP..

[ffjad]

Oil was same as usual, oil filter didnt have paper lable. Original cluster didnt come with the bike. I will unscrew the timing chain cover this weekend.

[The Mighty Gryphon]

Does the rattle go away when the rpm's go above 2500rpm?