Okay here is my issue - The rpms are really jumpy when I'm at idle or the bike is sitting and running. As the RPMS are jumping the headlights start to flicker and then it will continue to jump and flicker until it dies unless I put on the throttle and rev it till 3k and hold it there>

My bike is a 2001 Cbr600f4i 20k miles everything is pretty much stock

Recently I have replaced the voltage regulator, and the Stator. I also installed two LED headlight bulbs.

 

You may have fried the R/R again depending upon what type and where you bought it from.
Fitting LED headlight bulbs reduces the power that the bike is drawing significantly, this results in more heat that the R/R has to dissipate and as such can overheat very quickly.

 

This is something I’ve always struggled to understand, 99.9% of the time I ride with my lights off and my battery fully charged (on Optimate when not in use) so, presumably, the alternator is kicking out at least 60 watts more than the bike is consuming. Is the R/R just dumping that 60 watts straight into the frame / out through the cooling fins? Surely this is vastly inefficient.

 

OK, I’ve been sitting here thinking about this and here’s what I’ve come up with :-

Start the bike and the battery is sitting at, say, 13.2v and the R/R is holding the alternator to a max of 14.4v so, effectively, there’s 1.2v driving a current against the internal resistance of the battery (R). That gives you V*V/R watts (where V is 14.4 - battery voltage equals 1.2v) charging the battery to replace the power the starter took. As the battery returns to full charge its voltage rises to 14.4v and the current flowing drops to zero, the alternator is putting out no power and the R/R is dissipating no power.

Switch the lights on and it, in effect, pulls the battery voltage down enough that V*V/R equals 60 watts thus the alternator is powering the lights.

The R/R is therefor only passing the power being consumed and only dissipating power dependant on its internal resistance - that is lower for mosfet devices therefore it stays cooler than the old type.

Does any of this make sense or am I blathering?

 

Wow... that hurt my brain. Its a very long time since I had to delve that hard into physics
I'm not sure is the honest answer..
I was led to believe that under the current config the stator is always putting out its regulated feed a/c rev dependent, can't see any way of this being disabled as its a spinning magnet surrounded by the coils which will always generate an output
The A/C from the stator is then converted to DC by the R/R at a regulated max voltage c. 14.5v, any excess AC current not used by the bike and recharging the battery is then dispersed (shunted) though the frame as heat, Mosfets are faster and have much less resistance than the OEM unit therefore running cooler means less heat generated so in theory last longer.
A series R/R is supposed to disable the circuit when no load is required but back to the initial point is this just putting the heat into the stator as it has to go somewhere grounding it as apposed to the R/R?

 

If the end of the coils are open circuit then no power is being generated as no current can flow. Carry this further, if the ends of the coils are connected but by a very high resistance I would expect some power but only a small amount, increasing as the resistance comes down.

Carry it further another way, take the generator in a power station kicking out a gigawatt in the middle of the day - in the middle of the night it still has to spin at the same revs to sync with the 50hz mains but the draw might only be a couple of hundred megawatts, they cannot be dumping the rest through a heatsink.

I'm not convinced that the alternator is putting out full power all of the time, I think it's dependant on the resistance it's feeding into and, in this case, switching the lights on adds a low(ish) resistance in parallel to everything else thus lowering the overall resistance seen by the alternator.

If it is a you suggest then changing from filament bulbs to led lights would make no difference, as the max amount of power to be dumped,would be when the lights are turned off and that would be when the R/R would burn out.

 

all good points... and my head still hurts.
I can only come up with the fact that it is called a shunt type R/R in that it shunts the excess power as heat into the frame and this heat causes the components to degrade over time.
I believe that the majority of bikes now have a PMA (Permanent Magnet Alternators - Rotor / Stator) which have a fixed output and any excess is shunted as heat, whereas I imagine the power stations and cars etc have field driven alternators where the excitation can be varied to limit the output generated / required. Maybe

 

Definitely a fascinating subject and I’d love to know the answer :-)

 

Yep, me too Ed