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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Skrimps on April 20, 2016, 10:31:09 PM
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Hello everyone,
I found this site via google. I am looking at a 1988 K75. Would be my first BMW motorcycle. But it has an issue. I has all new fuel lines, injectors, filter and system (not sure if that means fuel pump or not) replaced but was told that when hot the fuel gets cut off and the bike doesn't run. It runs when it's cool but when it's hot the bike will not run, said it acts like the fuel cuts off. Mentioned some sort of fuel sensor, and said the bike runs fine when the sensor stays cool but not when it's hot.
Was thinking of picking it up as a second bike/project bike but not totally sure what I am getting into. Does anyone here have any guidance for me on this particular issue before I buy it?
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Sound like classic Hall Effect Sensor (HES) failure. Basically it senses when to fire the plugs. Runs fine when cold but fails when it heats up. Pricey buggers, there are threads here on how to diagnose and test.
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Sound like classic Hall Effect Sensor (HES) failure. Basically it senses when to fire the plugs. Runs fine when cold but fails when it heats up. Pricey buggers, there are threads here on how to diagnose and test.
First of all, thanks for the fast response. Secondly, how expensive? :mbird
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$419.95 at beemerboneyard.com Somewhere there is a link on how to just replace the components if you are handy with electronics. I'm sure someone will chime in
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$419.95 at beemerboneyard.com Somewhere there is a link on how to just replace the components if you are handy with electronics. I'm sure someone will chime in
Yeah that is a bit much. I am pretty handy with electronics so if this is indeed the problem replacing just the sensor itself wouldn't be an issue. Hopefully someone who has done it before will post here.
Thanks again.
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Was thinking of picking it up as a second bike/project bike but not totally sure what I am getting into.
A bike that old should probably get a complete going over by you to check the condition of electrical connectors, throttle body parts and balance. plugs, wiring, fuel tank condition, fuel pump performance, valve clearances, compression and so on. In the Technical Library card catalog, there are many links that will give you an idea of what to expect. If the bike has low mileage, you'll most likely need to clean or replace many of the previously listed components.
Another strategy is just to fill it with fuel, ride it hard and hope for the best.
Hopefully someone who has done it before will post here.
There's a whole lot of posts in the Workshop for reading while you're waiting to be served, Skrimps, about Hall sensors and everything else that riders have dealt with before with varying degrees of success.
For example, here's a posting (http://www.motobrick.com/index.php/topic,7884.msg59026.html#msg59026) where a bike starts out with a bunch of symptoms but ends up with a symptom like yours that's finally relieved after a lot of hand wringing and moaning here (http://www.motobrick.com/index.php/topic,8133.msg60553.html#msg60553), so maybe you can start with these.