Hi all!

After riding my 2009 KLX250S for 2 hours last Saturday, I realized, that the illumination of the display and the LEDs were flickering when the engine was idling.

On Sunday, I tried to start the engine only to find out that the battery was extremely weak. The engine did not start. The battery has been in the bike for 9 years and I decided to replace it with a new one.

Today I installed the new battery and checked the charging voltage, with the engine idling and at 4000 RPM:

Idling Voltage: 13.45V
Voltage @ 4000 rpm: 13.10V
Battery Voltage (engine off): 13.10V

The charging voltage seems to be low and even worse, it drops, when the rpm rises above idling speed. According to the service manual the voltage should be between 14.2 and 15.2 Volts @ 4000 rpm.

So I checked the alternator output, which is within specified range (all three circuits @ 0.8Ohm and 70V AC @ 4000 rpm).

All electric components seem to work fine. Even the flickering of the LEDs has disappeared with the new battery.

However, I think the regulator doesn't work properly and could not charge the old battery to provide enough energy for a start on the next day. And even now, it won't charge the new battery to its full capacity.

What do you think? Do I have to replace the regulator?

Thanks!

 

Check the ground wire on the reg/rec and search here for known issues.

 

You are the man! I had never heard of the ground wire issue. After you pointed me in this direction I googled it, soldered a new ground wire onto the connector and the charging Voltage is now 14.1V!!
And in addition to that the powersurges, I experienced now and then are also gone. Just as described!

Thanks so much!

 

Exact same symptom here. Got a used cheapo R/R on the way as a spare anyway, but checking the ground shortly. (get it? ha ha ha)