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Matt
Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 21725
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Hi, I have a BMW R1100 RT. I recently recharged the battery

Customer Question

Hi,
I have a BMW R1100 RT. I recently recharged the battery and then put the battery on to the bike again. I am getting full power in the headlights, indicators etc so everything looks like the battery is fully charged. However, when I put the key in the indicator and attempt to start the bike, I hear the engine refuses to turn. When I press the starter button, it makes a mm sound as if the starter motor is blocked and cannot turn
Submitted: 4 years ago.
Category: Car
Expert:  Matt replied 4 years ago.
Hello

If its not cranking then first check it can turned over by hand so double checking for any mechanical issues
If OK then check that the main battery cables are on tight and the terminals are clean and bright. Do the same for the engine / gearbox earth strap.
Then follow the main positive lead back to the engine and down to the starter motor, and check the connection at this end as well.

There should also be a small wire to the motor which should have 12V when you're turning the ignition switch to crank. If the 12V isn't there, check back along this wire for damage to the insulation or corroded connections

This 12V feed comes directly from the ignition switch so this may be faulty and need replacing

Check the resistance of the main positive lead that runs down to the motor as anything more than a few ohms and it should be replaced
Don't forget to try a jump start from another car / battery as its possible the battery is poor, if you have a voltmeter a healthy battery should read 12.7+V

also try substituting the battery for another as I've known a very flat battery to drag down the system voltage too far even with jump cables

one other thing to consider is that the immobiliser is faulty and preventing the starter from being enabled - however if the dash / ignition lights are on then this usually means that its off

If this is all OK then its possible the bike needs a new starter motor
Customer: replied 4 years ago.

Hi,


I have checked everything and I can now get the starter motor turning over. But it doesn't fire. I got a guy to help me push start the motorbike and the engine started for a few seconds and then stopped.


 


When I turn on the ignition, I see that the digital display that shows the gear the bike is in is not highlighting the gear. Could this be linked to the bike not starting.

Expert:  Matt replied 4 years ago.
Hello Paul

If theres no display then there's no power to the ECU so check over the ECU fuse and relay to ensure that there's 12V present