!!!==my new to me 85 K100 died, help !

[jeffhestand]

hello. new to the forum. just bought my first BMW after riding Jap bikes since 1977. Anyway riding 5 mins after getting new gas and she just dies. Will not restart... I need help as i have not gotten a Clymer manual yet. What should i check first to get her back up and running. I am reading fuel pumps ara a c ulprit on these machines? Thanks Jeff

[Chaos]

hmmm, did the thing sit with old gas?  that could be bad.  Check the big plug going into the computer under the seat. Take off the left side battery cover and pull the connector off and put it back on.  Sometimes that's all it takes. 

[frankenduck]

Usual suspects (not necessarily in any order):

1 - Hall Effect Sensor (the timing sensor for ignition) - If the bike starts right up again after it cools then it could be the HES starting to fail.  They usually exhibit symptoms of quitting once the bike has warmed up.

2 - Fuel pump - The fuel pumps are actually pretty reliable unless you let a K bike sit for an extended period.  (Like years, not months.)  When you press the starter button you should hear the fuel pump whining in the left front of the gas tank.  (Fuel pumps/filters on these bikes are mounted inside the gas tank.)

3 - Flaky connector for gas tank wiring.  I think that's more of an issue on the 86+ bikes though.

4 - Ignition switch getting old and flaky. Try flipping it on and off a few times to see if that will let the bike start.  Or it could just be that the soldering of the wires on the back of it has gotten old and failed.  Take the dash pad off, pull the plastic cap off of the back of the ignition switch and inspect the solder connections there.

5 - Check your fuses. (Under the left side cover.) Pull the top front corner of the side cover out and then slide it rearwards to remove it.


That should get you started...

Welcome to motobrick.com.....

[WayneDW]

What's your location, Jeff.  You may be close to someone who could take a look at it for you.

[johnny]

greetings jeffhestand...

welcome to motobrick.com...

the 1st thing i would check is the kill switch... then give us the low down...

key on... lights on... fuel pump on... side stand down... what do you see and hear... the more info the better...

j o 

[lukeman]

Mine died on my my first week when the connection under the seat came lose.  Spend like an hour screwing around with it, left it for the night. Next day I called a guy, pushed the connection in and it fired right up.. ugg..

What happens when you try to start it?  Hear the fuel  pump?  They are pretty loud so easy to hear.

[jeffhestand]

i do not hear the fuel pump . I had not tried the connection under the seat... im replacing with non oem purolator pump. And a new fuel filter. this bike is rough and i am replacing parts as i go along.

[motodude]

i do not hear the fuel pump . I had not tried the connection under the seat... im replacing with non oem purolator pump. And a new fuel filter. this bike is rough and i am replacing parts as i go along.

I can't speak for anyone else but I have to turn on the key AND hit the starter button (briefly) before I hear the FP.

You might also make sure the FP is getting power before springing for a new one.  I'm only saying that cuz I'm guilty of jumping to conclusions myself.

Also there is a good way to set the big FI connector and a better way.  The better way is to pull the FI computer out of the bike and set the connector.  On the right side, remove the batt. cover, take a pair of pliers and pull up on the black plastic pin that holds the FI computer in place.  The pull the FI computer out the right side (disconnect the large connector on the left side first).  Now you can really seat the connector well.  Making sure the latch at the "back" is latched, etc.   Re-insert the FI computer from the left side.  You'll need to kinda "shoe-horn" it in, but it will go.  And, re-insert the pin.  I learned this from Brian Curry (who has prolly forgotten more about K-bikes than you or I will ever know) and really like the positive feedback I get when connecting the FI computer in this manner.

Tom