Weird Electrical problem

6 replies to this topic
  • eu001939

Posted May 22, 2011 - 08:00 AM


Anybody has an idea on what could be the cause of this problem on a 2008 WRF 450 ?

-Cold start on battery works fine
-No problem driving , everything works fine.
- After some riding I switch off the engine (using the kill switch)
-Push the starter button, and the following happens : I can hear a relay clicking, but the E-start motor doesn't run. At the same time, all electricity is lost. The LCCD display goes blank and the red light above the on/off switch goes off.
At this point, the bike is dead, there is no electricity anymore. Trying the on/off and start button doesn't work.
In the end, I used the kickstarter and now the power is back and the bike is starting/running OK.
-For the next 20 min my odometer suddenly goes wild: the speed indicator is way off (did a 177 km/h with my bike...waow )
-Got home 20 minutes later. I switch off the bike, and try the whole precedure again and now everyhting works fine. For the rest of the day the problem didn't occur again...and the odometer works fine too

I have had this problem twice now but cannot find a cause.

Any ideas ? Is it the rectifier/regulator ? Or the start relay ? Or one of the diodes in the circuit ? And why does it happen sporadically and not all the time ?

:prof: going nuts trying tro find a cause...:smirk:

any help much appreciated....:smirk:

  • Derwud

Posted May 22, 2011 - 09:27 AM


I would check stator output with a fully charged battery. But, my guess would be a shorted battery.


Posted May 22, 2011 - 02:19 PM


My '08 did the EXACT same thing. After checking/testing everything, turns out my starter motor was shot. At certain points in its rotation it would dead short across itself and the bike would go crazy. I replaced the starter motor and put a 3rd new battery in it and all has been well for the last 2 months.

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  • William1

Posted May 23, 2011 - 08:36 AM


Yeah, I think the starter motor needs servicing or.. the starter relay is kerflunky.

  • eu001939

Posted May 24, 2011 - 10:07 AM


A starter motor problem seems indeed likely, but I checked the price for a new one and it's 480 Euro (about 700 USD). Would replacing just the brushes help ?

  • William1

Posted May 24, 2011 - 10:23 AM


Rarely do they actually need to be replaced. Often, taking it to an auto electric shop can fix it for cheap. It entails a complete cleaning, testing with a growler (gotta love that name), turning of the commutator, undercutting the mica insulator, new brushes, moly greasing of the bushings and bearing.

  • eu001939

Posted May 25, 2011 - 05:58 AM


:Well, it turned out to be a cheap fix. :smirk:

The + battery cable had come loose from the plug that's bolted to the battery. And I didn't see it until I disconnected the battery to take it out, and the plug fell off the cable...:smirk:

Attached the plug again and it works fine. Still have to go riding again, but chances are the problem is solved.



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