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  #1  
Old 24 Jul 2008
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Unhappy R850R Won't start

Helping a friend try to get his bike going,, got gas, good battery and weak spark,, changed the plugs but still won't go.. cranks good. Pulled the injectors and its getting gas but still won't go.. Is there any way to test the motronic to see if its working correctly?? How much fuel should squirt out of the injectors when cranking??
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Old 24 Jul 2008
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If the spark is weak then probably it's the Hall (ignition) sensor.

Also check the sidestand switch.

Small chance it can also be faulty ignition coil.
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Old 24 Jul 2008
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I think Margus is right about the Hall sensor - it sounds like it from the symptoms. The side stand isn't likely to be an issue because if it was then the motor wouldn't tunr over - it works like a kill switch.
As for the motronic - alos not likely . This manages the electronic fule injection but if you want to eleminate it you can reset it:
Ignition Off
Remove fuse 5.
Wait a minute.
Replace fuse 5.
Ignition on.
Fully open and close throttle TWICE.
Ignition off.
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Old 24 Jul 2008
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Unless there has been welding done on the bike you can pretty much forget the mototronic unit. They rarely fail.

I'd suspect one of the above mentioned faults and also check the main earth connection between engine end battery negative. From the plug thread to the battery negative should read zero. If it doesn't because the earth is via a lot of corrosion you need 14 volts in the battery to get a spark.

Andy
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Old 25 Jul 2008
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If the injectors are squirting petrol in pulses as the motor is turning over then the hall effect switches are functioning ...

How much fuel should they squirt? Well that depends on the temperature (like a choke - it will supply more fuel when the motor is cold). If teh engine temperature sensor goes open circuit (very hight resistance say over 500k ohms) then the bike will get too much fuel and flood teh motor.. been there done that.

Weak spark? check the coil for leakage, shorted turns.
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