Topic: Electrical question - and any suggestions are welcome

[750goes]

Hi guys,

Looking for some confirmation of what I have diagnosed, any other suggestions or things to look at – I’m open for alternate or different possibilities.

Have been running my sons GSX250 for several weeks  on and off while doing a restoration of sorts (de-rusting/painting etc). Have been putting only 2-4 kms on the bike around the local block to make sure everything is working ok.

Just put on some new tryes, refilled forks and decided it needed to be tested again.

Did 4.1 kms exactly and the bike conks out with a “pop/crack” of some sort and coasts to a halt – all power gone – no lights, no starter, no blinkers??

I turn around and roll home – only 200 metres… and push it up the driveway.

It must be electrical…check main fuse – its fine, check the battery (it is a rechargeable agm  12v12ah) it shows about 8 volts  - WTF - ..Turn on ignition – nothing – pull the battery out – and the underside is hot enough to nearly burn your hand.

I  have another spare batteyr (same type) – so I put that in – it has 12.8 volts. Bike starts and runs fine….

Check across battery terminals and rev it slowly to 5000rpm, voltage rises to 15.8volts and keeps going towards 16 volts… turn bike off

Start again and this time with headlight on high beam – rev to about 3500, volts climb to 14.4 and are slowly going up – stop motor again.

I think the voltage regulator/rectifier is officially stuffed?? It was not warm at all.

As per the manual I do not appear to have any resistance across any of the leads of the unit itself..

Any hints greatly appreciated…

Thanks for any replies

Cheers

[TwoTired]

If the regulator is getting the voltage from the battery correctly (wiring), and is connected to the alternator correctly.  Then it is not providing the proper regulation of the battery voltage.

[750goes]

TT,

thanks for the reply, will be getting a used replacement tomorrow, and will test it on the bike to see what happens.

I believe I may have overcharged the first battery by giving it upwards of 5000 rpm, for a period of a few minutes riding it around the block, and if the regulator was not regulating then I presume the battery died internally  - producing the dropping of probably two cells and the magical crack/pop I heard..and the generation of lots of heat..

I didn't rev so hard on the second battery for fear of doing the same thing.
Testing with no load it was quite quick to raise the voltage and kept going - no real sign of slowing down..
Then testing with H/light on high beam seemed to slow it down but it was still climbing past 14 volts so I decided to terminate any further testing..

Hopefully will be a simple fix... must clean all the connections to, and will check the wiring - from battery to reg/rec..

cheers
 

[bryanj]

Check that you have a good ground and battery voltage at the regulator if both are OK the reg is stuffed