Thanks Tony, I’m learning a lot about the charging system on this bike but the manual still confuses.
The stator coil resistance is within specification (1.0 ohm) when measured from any 2 of the 3 output wires of the rec/reg connector (plug) or direct from the Alternator plug (Ref 16.7.3).
Watched multiple videos on checking the rec/reg on a motorcycle - they all use the same method (as you describe earlier with forward and reverse bias). They are using the diode mode on the multimeter to check the diodes of the rec/reg. As you know this introduces a small DC current from the tester and is of course measured in volts. Both my new and old rec/regs pass this test and the new one is fitted to the bike.
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I get no resistance readings at all from either (new or old) rec/reg when measured at the plug, or directly from the rec/reg terminals. Certainly not those detailed in para 16.7.4 below. This is a mystery to me.
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I rechecked 16.7.2 ‘rec/reg output voltage’ again and in true 961 fashion got slightly different results.
Prior to startup bike showed 13.3v at the battery (clock voltmeter reads .5v below actual). Bike started first time as it has throughout the fault finding process. Bike warmed up and voltage increased slowly until it reached 14.5v. The stator is producing voltage within spec and the rec/reg is regulating voltage to within 14-15v. Leaving the bike to idle longer than I normally would, idle voltage reached 14.9-15v. As such, the charging system is said to be working normally IAW the manual. I have not got the same result each time I have tried this test.
Go figure! So why would the battery (or charging system) fail so quickly on the last ride - voltage plummeting (incrementally) to 7.5v within a few km, until the engine cut out? I am thinking battery still. Bike behaves normally when battery has just been fully charged. I’m wondering whether if voltage drops below a certain level whilst riding (because it is failing) it goes too low for the bikes changing system to recover.
Waiting for the Shorai dealer to action (or not) warranty. Failing that I will buy another Shorai (and
their charger). With 19Ah, 285 CCA, this battery has plenty of oomph when in good condition. I have reached the (very) end of my (very) limited knowledge in this area so any further feedback would be greatly appreciated.
Norton (still) rocks!