1996 Sport 1100 Charge Light Stays On

[jwinwi]

Morning All,
Finally got the carb sport back together after transmission rebuild. Bought 2 new batteries that both arrived dead: 1 was 11.45 the other around 10.9. Charged them and both came up to about 12.6. Took many attempts to keep the bike running - like it always does after the carbs are drained. Batteries had plenty of juice for all the required re-starts. Rode it around the block keeping revs over 4K. Charge light won't go out.
Battery cable connections are tight. Both ground wires on top of the trans are tight.

Guessing it has to be the regulator/rectifier or the batteries.
How do I check the reg/rec?
Any help appreciated.

John Wendt in Wisconsin

[guzzisteve]

Hey, Here's a manual---

https://guzzitek.org/gb/ma_us_uk/1100/1100SportCarb_Atelier(I_GB).pdf

You need to locate the yellow wires from stator going to regulator. Check AC voltage put out by stator.
Next check DC voltage put out by volt reg going to batt.
Sometimes it's a cooked connector.

[jwinwi]

Thanks Steve!

[guzzisteve]

Manual gives you the specs for voltage at AC in different rpm's. I have found if that is correct than regulator is bad.

[Old Jock]

Agree with steve for the checks

I'd have a look at all the plugs on the reg/rec, there are 2 which on mine could come apart quite easily and any connector associated with the yelow wires, they carry a lot of current and the connector can fry as I remember

It's also an idea to add an extra grounding strap from the reg/rec to a good solid ground.

Otherwise I'd start as steve said with the AC output to Reg/Rec from the Alternator then check the DC output from the Reg/Rec. Remember to check the DC with a fully charged battery as a discharged battery can pull the voltage down

[jwinwi]

Agree with steve for the checks

I'd have a look at all the plugs on the reg/rec, there are 2 which on mine could come apart quite easily and any connector associated with the yelow wires, they carry a lot of current and the connector can fry as I remember

It's also an idea to add an extra grounding strap from the reg/rec to a good solid ground.

Otherwise I'd start as steve said with the AC output to Reg/Rec from the Alternator then check the DC output from the Reg/Rec. Remember to check the DC with a fully charged battery as a discharged battery can pull the voltage down

Thank you John!

[Guzzidad]

   To check the reg/rec check for continuity between any of the leads ( 5 of them if I remember right ). There should be NO continuity between any of them. Also. there should be NO continuity between any of the leads and the case ( body ) of the reg/rec.

[jwinwi]

   To check the reg/rec check for continuity between any of the leads ( 5 of them if I remember right ). There should be NO continuity between any of them. Also. there should be NO continuity between any of the leads and the case ( body ) of the reg/rec.

Thank you Guzzidad. Your experience with the Sport is most appreciated. 

[Chuck in Indiana]

John, the most common failure is the rotor. The first thing I do in a no charge situation on that system is check for 12 V at the brushes. I assume you have that because the light is working. If so, isolate the brushes and check resistance between the two slip rings. From memory,  it should be about 3 ohms. Either open or shorted, and "She's dead, Jim.."

[Tusayan]

Look Ma, no brushes 

[Chuck in Indiana]

Look Ma, no brushes 

Doh! I thought they were still using the Bosche on the carb spots.  My bad. Pay no attention, nothing to see two posts ago..

[jwinwi]

Finally checked out the Spot's charging system and the problem is a weak connection between the stator output and regulator input wire connectors.
Melted insulation close to the connectors on the stator output.
Seems like the reg/rec tests OK.

[Chuck in Indiana]

About all these heat related problems can be cured by a DeOxit job at the connectors every couple of years or so.