We are assembling a 998 engine with 998 cable harness into a 748 frame (trackbike) and we have everything up and working. But - the regulator gets insanely hot when the engine is running. Even the cables to the regulator gets very hot. The voltage reads 14.4 volts when the engine is running. That seems high to me compared to the 13.4 volts on my 999 but it should be within the acceptable range. Any ideas? First trackday in 14 days... br Jim
My 998 doesn't get that hot so it does sound like you have a problem. I would agree it could be the regulator.
Yeah, my best guess as well. It is drawing way too much current, maybe some of the diodes have failed. thanks Jim
If you don't get time to change it, it's worth while cleaning and checking all related earths and return connectors as this can contribute to the heat and the higher voltage demand.
Here's what I did below... Mosfet conversion 848 - Regulator / Rectifier soloution | Ducati Forum Acceptable voltage range should be between 13.0 - 14.9 whatever it runs at should stay fairly consistent no matter what throttle Any help?
Yeah, we have found another regulator for testing, it will arrive in a few days. Will let you know Jim
Check the earths, I always run an additional earth on mine and I've never had one fail in 20 years! Jeez, I sound like Mr R
Jim, 14.4v at the battery is not that high on the 520w 3ph systems of the later 9xx/748(assuming your lights are all off), they should run up to 14.5 as that is the maximum setting for the regulator control voltage. If you see anything over 14.5 or less than 12.8 then start to worry. Under most conditions with a healthy battery it will run around 14v with the normal operating range 14v +/- 0.4v from approx 2k revs upwards. As far as the regulator temperature goes you will get this overheating if you have high resistance on the connector for the three yellow AC wires. If this is not addressed quickly it will lead to a dead regulator, typically you will find one of the pins (at least) getting very hot or scorching the plug body or even burning of the pins. I strongly recommend replacing the connector with a 15A clamping connector (do not use bullets), crimp or solder the wires and heat shrink insulate them. Having had exactly the same problem on a brand new reg with a brand new battery I soldered mine, since then (2009) the reg only gets warm even in traffic on hot days and I get a very consistent voltage and long battery life.
Good advice, I had a 916 that melted the (stupid) plug between stator and regulator and I soldered it too. It's a really bad design to have TWO plugs between stator and regulator! He tried fitting a 2 phase regulator and it worked fine without getting hot so he's looking for a new 3 phase regulator as it must be faulty. tnx Jim
