I thought I would post this for reference by others out there. I recently diagnosed a faulty regulator on my 2001 996S. I was measuring less than 12VDC output which was not enough to charge the battery during normal use. Following a little research I decided to try out the popular Mosfet based regulator: Shindengen FH020AA. These can be fitted to most modern motorcycles, but I didn't find much evidence that people had fitted it to the 748/916/996 family (although I am certain many have). If buying the rectifier online beware of Chinese copies that sell for around £35. They usually say something in the ad like "replacement for FH020AA". The genuine FH020AA costs around £115, has a metal back and FH020AA stamped onto one end. I also bought a cable kit online which allowed the replacement rectifier to plug easily into the factory wiring loom. This was specified to fit a Triumph in the ad, but the plugs looked the same. The plugs are almost perfect with a minor being that the DC output side does not clip together - it does join the factory harness, but no securing clip exists. Nothing a little tape or cable tie cannot solve. The other issue was the rectifier does not fit straight onto the factory heatsink, where the old rectifier was. I chose to drill a new hole into the heatsink and used a single bolt and nylon nut to hold it in place. This seems to work, but I'll see how it goes dispersing heat with less contact patch on the factory heatsink. All connected and with the bike running I am now charging the battery at 14.2V. Quite a lot better than the factory rectifier (even when it was working well).
How hot does the regulator get at tickover and at 75% revs without any lights on..... I'm assuming you still have a lead acid battery. Do the test after 10 minutes tickover to allow the battery to recover from starting the bike. If you are local to Heathrow we can use my FLIR kit to measure it.
Sam, the stock Shindengen regulator rectifier on the three phase systems will run at the same sorts of voltage and speed when it is operating normally, typical operating range is 13.2 to14.6v with it sat around 14-14.2 for much of the time depending on battery state and engine speed. The most important thing is to watch the cleanliness tightness of the three phase wires (the yellow ones) and their plug. That plug is where most of the issues come from - it should not get hot and any sign of overheating at its pins should be resolved quickly.
Air con, since removing the plug on mine and solder through jointing the wires it gets barely over 30c in most conditions, before soldering it got almost too hot to touch in just a few minutes at tickover. This is the fourth fitted to the bike and it has lasted for 6 years. I found no benefit from the Electrex one but that was without sorting the connector issue out once and for all
Unfortunately these external connections to the stator are prone to high resistance due to corrosion. This leads to heat and then connection failure. The stator (basically three generating circuits in one) is still making energy, which cannot be passed on to the bike. This results in very high coil temperatures within the engine. Since the remaining phases still offer enough power to the bike we don't notice until it's too late and our oil looks like someone emptied the toaster in it. Sorry to any electrical types out there, just tying to make the message easy to understand.
Yes still running a lead acid battery. No plans on changing to Lithium. No idea how hot it gets yet. Haven’t been able to test it properly. I used to be near Heathrow. But I’m now about 1700km away. Based near Perugia Italy.
Brilliant. Having worked on bikes since I was a kid I'd never seen this sort of failure until just a few years back. We always cut out the connector and solder the wires. It makes sense.
Soz.... thought I may be able to help... track down a decent AC or fridge engineer he should have a FLIR gun (tool).
