GT380 Charging Issue

[Laurence]

Hi All
I have a charging issue on my 380A that I am going to investigate using the many previous posts. But cannot find any info on how to clean and adjust the regulator, does anyone have a link or the info ?

I am going to go through all the checks on the alternator and cleaning contacts etc and earths on rectifier and regulator, but this issue is when you switch the lights on or indicators with the engine at idle the engine dies. Have done some checks on battery voltage, and it seems its not charging at low revs and at over 3000 rpm its bouncing all over the place and is far to high at 16 & 17 volts so is probably frying the battery.

Cheers
Laurence

[barney01]

I know this is from my 550 manual but lots of info on VR and how it adjusts. I think its the same set up as 380.
http://www.3cyl.com/mraxl/gt/manuals/gt ... 550-49.htm

[Laurence]

Hi Barney
Thanks for this, looks very useful. I will use this to start checking things over the Easter weekend.

Cheers
Laurence

[Laurence]

Hi All
Well I think I might have found the issue, well I certainly hope so. The positive brush is worn so it is barely touching the rotor . See picture . So have both on order. Have cleaned the rotor up , and all contacts involved with the charging system . Also have replaced the earth wire for the regulator as looked as at some point the insulation at the regulator end had melted slightly.

[Alan H]

. So have both on order.

Hope you haven't ordered genuine as they are bloody expensive - have a look HERE (clicky) - second post and click the links.
And
http://www.kettleclinic.co.uk/kcforum/v ... t+charging
http://www.kettleclinic.co.uk/kcforum/v ... it=brushes

[Laurence]

Hi Alan
Thanks for the link I had ordered some genuine ones from discount bike spares , as I wanted a quick fix so I could get it back on the road. But have also ordered a pair of these Valeo alternator ones as per your link so will have a go at making up some spares fo when they need replacing.
Thanks again
Laurence

[barney01]

Hi Lawrence yes i used the valleo ones after Alan pointed them out. They worked fantastic and dirt cheap!

[Laurence]

Hi Barney
That's great to know, I make up some spares with the springs and brackets from the old ones.
Cheers
Laurence

[Laurence]

Hi All
Have fitted the new bushes after cleaning up all contacts in the charging system. Have run some tests , see results below , these make me think there is still something not right.

So started the tests with a fully charged battery which was showing as 13.04 volts .

RPM. Battery Voltage
1500. Between 11.8 to 12.4 (depending where revs had been previously)
2000. 13.4 to 14.1
3000. 15.0
4000. 15.0
5000. 14.8

With lights on at tickover (1500 RPM) voltage drops to 11.6.
Regulator internals look in good condition and adjuster nut & screw still in factory set position judging by paint marker.
I am not very experienced with electrics so any advice would be appreciated.

Cheers
Laurence

[Alan H]

I would suggest that you have one or more of the following;
A bad connection between battery and earth, or battery and regulator (which is the favourite) so that the sensing voltage to the reg is low and makes it think that the battery is more discharged than it really is. Or perhaps the battery is either on its way out or has low water/acid level(s) in the cells.
Last case is that the regulator needs tweaking. Clean ALL the contacts between battery and reg and everything on the earth side, including the earth to the reg.
Neither type of alternator should go so high voltage wise. See attached test and charging info. If anyone wants a copy of the entire service manual, just PM me with an email address - it's free and it covers all models at the time. Bear in mind that the later models have the same charging circuits and some other details.