Stator cover heat

mech 1 twa · Jul 8, 2015

After recently swaping a Gen 2 Engine into Gen 1 bike i've noticed stator cover gets hotter faster than rest of engine.

I had a cover on original engine, carbon fiber one. Never noticed, or thought about it.

This engine heats up cover faster than rest of engine, 4-5 minutes get s pretty hot. I'm having no issues, charging system normal voltage.

I need someone to cold start their bike and feel if stator cover heats up faster than the rest of the engine. ?????

Could be normal. Any help.

Over 1500 miles since swap. Happy so far.

wfooshee · Jul 8, 2015

Carbon cover would be a heat insulator.

ionbeam · Jul 8, 2015

Are you running the Gen II stator with a Gen I R/R? The Gen II stator really should be used with a Gen II Rectifier/Regulator to handle the extra 100 Watts of power. The Gen I R/R is at the top left of the engine by the radiator fill. The Gen II R/R is at the lower center of the back of the engine at the rear swing arm pivot.

mech 1 twa · Jul 8, 2015

Gen II stator, Gen I Rec/Reg.

I know the output is higher, 100w.

Just interested if this is normal, or if i have a future problem.

Haven't tried to measure the temp. yet. Cover just gets hotter than the rest of engine on a cold start.

Need some feedback . Start bike put hand on stator cover, then on clutch cover. Is it the same or does stator get warmer faster.????

Doesn't get hot like a short, or over load. .Just heats up faster.

ionbeam · Jul 8, 2015

mech 1 twa said:
Gen II stator, Gen I Rec/Reg...I know the output is higher, 100w...Cover just gets hotter than the rest of engine on a cold start.
Need some feedback ...Is it the same or does stator get warmer faster.????

Doesn't get hot like a short, or over load. .Just heats up faster.

Sorry, I can't answer your question in a way you are looking for. I suspect every Gen II stator dumping into a Gen I R/R would get hot pretty quick. I would expect the rapid heat rise to be normal for this situation, and I bet the R/R is getting hot faster than the engine too.

I would expect something will die sooner than it should unless this situation is remedied.

Fred W · Jul 9, 2015

More important than it getting warm faster, how hot is it getting? If it is over heating then that may be a problem. Getting warm fast is not. If you have a IR thermometer it would be quick and easy to compare readings to other bikes.

What Professor ionbeam is telling you is that your configuration is non-standard. You may be one of the few people on the planet that are dumping the added 100 watts of power of the 2nd Gen alternator into a 1st Gen shunt regulator. What happens on anyone else's standard configuration 1st or 2nd Gen alternators is not comparable or significant. IOW you might want to look into configuring a different (better) R/R in there.

Twigg · Jul 9, 2015

Not sure how the R/R is relevant to this issue. It's nowhere near the stator cover and it either works or it fries.

I guess I'm not even sure this is an issue at all ... lmao

Fred W · Jul 9, 2015

The regulator type is significant because the design of the 1st Gen R/R is different than the 2nd Gen's. 1st Gens have an SCR shunt type regulator, which means that it takes the full output power of the stator and dumps some of it to ground (through a low resistance) to regulate the output voltage at ~14.3V. That means it will be pulling the full power from the stator at all times regardless of the actual load

The 2nd Gen, and I assume 3rd Gens also, is a series MOSFET type regulator (Shindagen FH012AA) . Series type regulators do not pull the full current from the stator at all times like the shunt design does, and the FH012AA design is rated at 50A @ full load so it will withstand the higher loads available before the alternator sacks out.

I retrofitted a Shindagen MOSFET regulator to an Aprilia Pegaso I had, which had abysmal voltage regulation with its stock series type regulator. It improved voltage regulation dramatically as well as running much cooler, therefore wasting less power.

PS - You'd look pretty silly without an ass, Twiggy

Twigg · Jul 9, 2015

Fred W said:
The regulator type is significant because the design of the 1st Gen R/R is different than the 2nd Gen's. 1st Gens have an SCR shunt type regulator, which means that it takes the full output power of the stator and dumps some of it to ground (through a low resistance) to regulate the output voltage at ~14.3V. That means it will be pulling the full power from the stator at all times regardless of the actual load
The 2nd Gen, and I assume 3rd Gens also, is a series MOSFET type regulator (Shindagen FH012AA) . Series type regulators do not pull the full current from the stator at all times like the shunt design does, and the FH012AA design is rated at 50A @ full load so it will withstand the higher loads available before the alternator sacks out.

I retrofitted a Shindagen MOSFET regulator to an Aprilia Pegaso I had, which had abysmal voltage regulation with its stock series type regulator. It improved voltage regulation dramatically as well as running much cooler, therefore wasting less power.

PS - You'd look pretty silly without an ass, Twiggy

Nope, my ass is fine.

That was a complete explanation, thank you.

Fred W · Jul 9, 2015

Sorry, forgot to add the ob-smilie-thingee... :lmao:

Twigg · Jul 9, 2015

Fred W said:
Sorry, forgot to add the ob-smilie-thingee... :lmao:

I wasn't offended .... I was wondering how the stator could be retaining heat, regardless of the type of Regulator. If indeed it is retaining heat 'cos no one has measured it yet

TomInPA · Jul 9, 2015

There are some significant wiring differences between a Gen I and Gen II regulator and the ignition and battery as well. I would think Mech 1 would see an improvement in charging rate with not only the series regulator, but also a larger gauge wire to the battery. I recall Gen II bikes had some deficiencies in this regard, or it might have been another Dcarver nightmare; I'm not sure.

Big Sky · Jul 9, 2015

The knowledge often displayed here is outstanding. Wow, Fred!

Donal · Jul 9, 2015

Fred W said:
The regulator type is significant because the design of the 1st Gen R/R is different than the 2nd Gen's. 1st Gens have an SCR shunt type regulator, which means that it takes the full output power of the stator and dumps some of it to ground (through a low resistance) to regulate the output voltage at ~14.3V. That means it will be pulling the full power from the stator at all times regardless of the actual load
The 2nd Gen, and I assume 3rd Gens also, is a series MOSFET type regulator (Shindagen FH012AA) . Series type regulators do not pull the full current from the stator at all times like the shunt design does, and the FH012AA design is rated at 50A @ full load so it will withstand the higher loads available before the alternator sacks out.

I retrofitted a Shindagen MOSFET regulator to an Aprilia Pegaso I had, which had abysmal voltage regulation with its stock series type regulator. It improved voltage regulation dramatically as well as running much cooler, therefore wasting less power.

PS - You'd look pretty silly without an ass, Twiggy

That was what I used to think but if you have a look at the Shindengen site you will find the FH020 series RRs are in fact shunt type but they do use MOSFETs which are very efficient.

They have an SH775 series type RR which can handle up to 35 amps. Higher current devices are (and have been for some time) under development.

I have heard (somewhere) that they are susceptible to problems at higher frequencies (higher engine RPM).

mech 1 twa · Jul 9, 2015

Tonight I took several engine temp. readings with an infrared temp sensor

Had a powerful fan blowing into radiator for 1 st part of test.

Stator cover, oil filter and side of radiator from left rear. All measurements at 6"

Amb temp 84 degrees. cold start of engine.

stator cover oil filter radiator

2 minutes 90 degrees 100 didn't measure until 2 bars

4 109 102

6 127 117

8 144 134 175

10 158 151

12 172 162 200 3 bars

14 183 172 206

16 186 177 removed fan let engine heat up 4 bars 230

18 202 max 188 fan cycles 220-230

Heat doesn't seem excessive, engine is designed to operate at these temps.

Experiment will continue.

Thanks for all the feedback.

1500 miles and counting since swap.

wfooshee · Jul 9, 2015

I still think you're comparing apples to cat barf because you had the carbon-fiber cover before, which is a heat insulator. It just won't show the same temperature on the outer surface as the metal cover.

I'm sure the difference in regulators is significant, too, and I wonder what the life expectancy of your regulator is, now.....

mech 1 twa · Jul 9, 2015

New engine doesn't have carbon cover, measuring metal temp.

Never gave old engine any thought about temp. never measured it. Replaced it for transmission issues.

Several aftermarket Rec-Reg out there for sale. 03- 11 Fjr . all the same #'s

Started this thread, just wanted someone to measure their bikes stator cover temp. and see if it got hotter faster.

Don't really know if its a problem or not.

Extra 100w isn't at idle, Both measured at 5000 RPM. Both stators output close at idle.

ionbeam · Jul 10, 2015

This may turn out to be yet another problem with the FJR but we just hadn't noticed it before. People have also found problems with the engine speed regulation. With the transmission in neutral and the throttle turned up to 3-4k rpm and held there for a while the engine speed starts to hunt around. If the throttle is whacked open and closed rapidly, after 10 or more cycles the engine starts to make a rapping noise. There are also problems when the motorcycle is on the center stand and someone shifts up and down through the gears as fast as they can over and over and over again. A search should take you to these threads, though some are around 2-3 years old. The stator heating may be in this same group of issues.

Donal · Jul 10, 2015

For what it costs I would go with the suggestions from Fred & Ionbeam. Simply replace the OEM RR with the Shindengen FH012AA and forget it. You should be able to find one on E-Bay pretty cheap.

Stator cover heat

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