The electrical issues had been getting slowly worse with the engine misfiring at low revs. The Digidash displays the battery voltage but like a lot of readings on the Digidash the numbers jump around a bit. Some of the readings were lower than I woudl expect, especially since a new battery was fitted recently.
First thing I did was fully charge the battery using my new Optimate 6 charger, to get an idea of the expected battery voltages
Disconnect charger and allow battery to stand for 30 minutes. Check the battery voltage with a digital voltmeter. The voltage should be around 13.3 to 13.5. If the voltage is less than 12.5V, replace the battery. The fully charged voltage measured was 13.4V. At tickover a stable 12.7V was seen.
|Spent a bit of time working on Fury today. To avoid the need to use the headlights to be seen on the road, I've fitted some LED side light bulbs and also some LED daytime running lights. The picture doesn't really do them justice but they are very bright. They come on when the side lights are on.|
With a known good battery into bike and start engine. After warm-up, bring engine speed up to 5000 rpm and measure the battery voltage at the same time. The voltage should be about 14 to 14.5 volts. If the voltage is greater than 15, the problem is most likely the rectifier/regulator. If the voltage is less than 13.5V, then it's either the alternator (stator coil) or the rectifier/regulator, or possibly even both.
A known regular problem is that the 3-terminal stator coil connection fails and the resultant heat from the I*R drop melts the connector. The red-wire contact on the rectifier/regulator connector also has a history of oxidation/corrosion.
I first checked the connectors to the rectifier and worryingly, one of them was not clipped in fully and came out far too easily. The connector terminals looked in very good condition though. Having pushed the connectors fully home, the voltages seen on the battery at idle looked much better. I took the car out for a test drive and was seeing much more reasonable readings too.
I'm pretty sure the regulator is not the issue.
To check the stator coil (alternator), measure the coil(s) resistance at the 3-terminal connector with an resistance meter. The resistance between each coil (three in total), should be 0.45 to 0.55 ohms @ 20ºC. If not, the stator coil needs to be replaced.
I can easily believe the alternator coil is a problem because my issues started last year after a road trip with the headlights on for about 3 hours. The headlights draw quite a lot of current, especially compared to the single unit found on the R1 motorbike.[Previous] [Next]