The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: dogshome on January 10, 2021, 11:29:54 AM
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Whilst idly being idle between work and covid/weather-induced nothingness, I decided it was time to look at the charging system. The battery never gets topped out and in the cold after a couple of weeks idling (being idle I mean) did not want to go. Looking at the upgrades they appear to based on a standard 8 big / 3 little diode block from several older cages. See pic. From Suzuki Balena and Gran Vitara and others.
It has 8 big diodes and 3 little ones and is therefore identical to the RYB&N plus sense that our airheads have.
They are about £23 delivered 8)
Bit of PCB material, ferric chloride, etc pen, PCB dpade connectors, some copper rivets, bit of time and measurement = ~£45. A few more spades, bits of wire and we are over £50.
So i'm thinking the £90 delivered for a full, bolt on equivalent is pretty good!
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another pic
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What kind of riding do you usually do, slow speed city type riding commute to work??
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Ok we are having some serious tinkering fun now ;D
Here's what I did
Convert the charging system to an "A" circuit and install a
Yes you guessed it
A GM 10SI voltage regulator and diode board
Then change the headlight and taillight bulbs to LED
Even with a halogen bulb in the head light
After the battery has recharged from starting the bike. I have 13 volts at 1100rpm
Note that unlike the above diode board the 10SI does not have the 4th rectifier pair that is helpful at slow rpm. I had to add it
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Whilst idly being idle between work and covid/weather-induced nothingness, I decided it was time to look at the charging system. The battery never gets topped out and in the cold after a couple of weeks idling (being idle I mean) did not want to go. Looking at the upgrades they appear to based on a standard 8 big / 3 little diode block from several older cages. See pic. From Suzuki Balena and Gran Vitara and others.
It has 8 big diodes and 3 little ones and is therefore identical to the RYB&N plus sense that our airheads have.
They are about £23 delivered 8)
Bit of PCB material, ferric chloride, etc pen, PCB dpade connectors, some copper rivets, bit of time and measurement = ~£45. A few more spades, bits of wire and we are over £50.
So i'm thinking the £90 delivered for a full, bolt on equivalent is pretty good!
The diode board you are looking at is definitely more robust than the original
But I think you will see the greatest improvement switching over to the "A" type charging circuit and regulator
here is a good website to shop Alternator parts until your eyes bleed :idea2:
https://store.alternatorparts.com/rectifiers-mitsubishi.aspx
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Here is the exploded view of my Delco diode board
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:thumbsup:
So, type a circuit. Separating the rotor coil return. I'm not quite sure of it's function as it is on the output of the regulator. Is it simply to ensure a good rotor earth connection free of currents around the power side of the system? Or simply keeping the regulation icomponents solated from the power? I guess the latter, after some thought.
What I do see is my digital volt meter dropping to 8 or less volts when cranking today at 1C and the battery not returning to much more than 12.1V after a few seconds. 30 mins on the charger got her going, but the drop is still awful. My voltmeter is connected to the (unused) heated grip supply, not direct on the battery, so it will see cable volt drop.
I've replaced the battery negative wire and will follow up under the starter and diode covers now. 860 high compression, cold weather and 40 year old wiring is marginal. Potentially manky rectifier and regulator connections combined with maybe a bit of regulator drift won't be helping her start.
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Having looked at the alternator pron site listed above, I might chuck 1/2 doz avalanche diodes on the back of the pcb. Wish me luck with the solid metal mount nuts...
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I can make one of these cheaper ignoring all my time, but not much. There can't be a living in selling kit like this. But I'm glad someone does. I MOVed away from the Avalanche idea....
The regulator intrigues me. Why don't lead acid batteries do something sensible? Just bolt a 13.8V 3 pin switching reg in and Bobs your uncle. No, they have to do some funny chemical stuff and refuse digital control. Since I do long and short journeys in weather ranging from 1C to 30C, I might apply my brain to the 3 or 4 wired gizmo. If only temperature compensation. At least I found out what a smart alterator is so I have a clue if I break one in the future.
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Their are other things you can do to help with keeping the battery up
I have done all of this because of using heated gear
#1 Change out the head, brake and taillight to LED
#2 Or be able to shut off the Halogen headlight and run your LED spots instead but still get a LED tail light bulb
This what I do since I no longer have an LED Headlight bulb
LED bulbs really help the charging system, They make the high out put alternator conversions obsolete
Here is a picture of my volt meter at idle with just the LED floods and led tail light on
I do not know what the voltage at idle would be with the standard Bosch regulator this is with my Delco reg but I am sure it would help a lot
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Don't waist you money on the expensive PC board Tail light conversions
Just get the Sylvania ZEVO LED's
I have them in the tail ,stop and turns
red for stop and tail
amber for the signals
trimming is required to fit tail light
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Swapping the positive cable to the starter motor was a bit of a game. This expanded into moving the fairing bracket to where it should be (between the cables popping out of the front cover), and general snipping of tie wraps and cleaning cable looms using baby wipes. Both ends of the big cable were quite manky as was the battery ground strap.
Getting the diode board in was a bit fiddly with RT fairing and me at ground level, but quite satisfying to move the 40 year old wires, check and clean. I'd done the brushes 3,000 miles ago and they are still OK. The electronic regulator also had manky connections and obviously has never been off. Brass brush (also used elsewhere) and a few drops of ACF here and there. The PCB was a bit scabby, so that was cleaned in solvent but otherwise looks fine. Even the 40 year old sticky fabric tape came off AND stuck back down again.
The power transistor is a BD244A PNP 6A plastic package type if anyone ever needs to replace it.
I ran out of time to fit my FIAT potted modern regulator as it wants some spades and an aluminium plate making up.
The voltmeter now reacts as it should (13.8V just above idle) and my battery charger doesn't kick in when back form a short 30 minute ride any more :beerchug: This is more due to the cleaning and reterminating more than the diode module - the original tests fine and shows no solder heating or corrosion. The timing cover has cast-in lugs on mine so I didn't need the solid mounting kit as there were no rubber bobbins.
I am already LED'd up (apart from indicators which I might do at some point) as that is a no brainer with a tiny engine speed alternator.
About 5 hours messing with all of this today. 1hr to change both sets of rear pads on my lads Kia i20. sigh.
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Well, look on the bright side - Kia brakes, every couple of years but you're good for another 40 years on the electrical! :ROTFLMAO:
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"Carry on Tugging / Cleo" ;D
Tugging cables that is. So the tank is off, wiring and relays all look nice and clean under there. Hm, now that tatty one disappearing under, where does that go? Why do I get a hard stop on right lock and a squidgy stop on left lock? What's that manky bit of black mummified bandage hanging down under the handlebars? Why is that loom the wrong side of the brake line and catching on the steering lock.....
So baby wipes are great for cleaning manky wires :)
My bike looks great from the front still (RT fairing) but like some martian weed in black from the headlamp back to the regulator. It'll all go back in. Yes it will. All of it. I have to say the quality of the wire, crimps and all the electrical stuff is noticeably better quality than the typical jap bike of the period. Nothing has actually snapped, perished or dropped to pieces. Apart from the black tape, which I may try to sell to the British Museum. A few drops of vinegar and an old Camel tobacco tin should do it.
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I use Tesa tape to replace the loom covering
It does hold fairly well and does not get all sticky and gooey like friction tape or vinyl electrical tape
You can cleanly unwind it to make changes to your harness.
It is just like the original.
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Major FAIL with the regulator. I now know there are NPN and PNP types. Airheads use PNP type that drives +ve to the coil, Fiats and several others use NPN that expect the coil to be connected to +ve and then sink current down to ground. Live and learn. Or is that LIVE! and learn?
There does not appear to be any info as to which is which except to find the alternator it fits to and scrutinise how the brushes are connected. In true Haynes/automotive style (make it really complicated) this isn't immediately obvious.
To be fair, the original one is solidly designed and efficient. Mine is clean and in good condition. A few more ergs might occur with a MOSFET driver and temperature compensation would be nice, but your average Ebay special or 20 year young alternator bolt-on doesn't do that.
13.8V at 2,000 and 12.9V at 1,000V with the lights off is good enough. Apart from a few specialist marine circuits (where a lot of expensive fried batteries stranded in a force 8 on the North Sea might be a problem) I've not found anything to crib.
P.S. That black tape is great stuff. I bet you could stick wet nappies with it :-)
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Yes their is 2 types of charging circuits
The airhead comes from the factory with whats called a "B" circuit
Regulator controls the B+ going to the field
The GM Delco I use is an "A" circuit
Controls the B- going to the field coil
If you go to the online store I posted the link to many of the REG's description will tell you if its A or B
It is easy to isolate the ground on the brush holder if you would like to try it again
I have been wondering if the A circuit reg in general comes up quicker or if it just the higher set point that the GM reg has that causes it to perform better
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Thank you 😎
Typical auto, why call it a and b when it's npn and pnp?
Npn do work better than their pnp equivalents, but I don't think you would notice on something relatively sluggish like an alternator field. How hard and how fast the circuit is designed to turn on might be though. if it is on the high gain and minimum lag side, you might notice faster response and a little instability or hysteresis. Lower gain and or larger lag might mean better stability, even some slow drifting.
I think the lag introduced by the capacitors in these circuit is is a bit arbitrary. If it doesn't oscillate, then it will be close enough for jazz. Without a scope, lots of revving up and testing I can't see me messing. Someone knows.......
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The caps vs resistor sizes in the BMW regulator suggests it's not slugged very much i.e. fast response. MOSFETS theoretically give better dissipation when being switched, but not at the sub 500Hz we are looking at. So I did a quick test on the Cargo NPN one I have here:
Only running a lamp load of ~300mA not 3A expected. VCE is 30mV. It could be a BJT of FET in there. The BD244 in the BMW regulator is typically about the same at this current. Rising to around 200mV at 3A (bang in it's saturated design range). So I don't think a MOSFET with it's effectively 0 RDS (and 0 volt drop) is going to make any difference.
What I did see with this Cargo unit it that it doesn't turn off until 14.6V ~ 14.7V. Getting marginally higher as it warmed up (eek!). So I think that is why your system is performing 'better' - Not sure I want it that high even with an AGM battery. Cold weather and trips to work probably OK, a run to the coast in summer, maybe not.
[Yes my meter is ancient, it is still very accurate and safe. Yes it is a Maplin special. I bought a new one for work recently, simply to avoid questions about it's suitability on LV busbars and drives. Both have proper HRC fuses, over voltage and overcurrent protection and are shrouded internally. Hasn't killed me in 40 years of use....]
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MOSFET, N Channel (NPN style).
PT001
VDSS=150V ID=30A RDS (ON)=0.049Ω
Surface Mount package
Model Brand package Polarity VDSS(V) ID(A) RDS(ON)(Ω) VGS(th)(V)
PT001 MORE SOT-252 N CHANNEL 150 30 0.049 ?
Couple of transistors, flyback diode and a zener. Just tiny. Not a great RDS hence volt drop I measured. Very cheap and similar to a decent BJT in terms of performance here. Too small to reverse engineer with a P channel MOSFET!
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The "A" and "B" terminology predates transistors
Not sure if the terms PNP and NPN were used before the advent of transistors
A and B was used to describe old generator systems also and was very important to know what you had when diagnosing them
The Optima battery likes the 14.7 volts that the Delco reg tops out at
Got 6 years out of the first one and it did not fail catastrophically. It just got to weak to get good spark and cranking speed
I do know if you put the Delco reg under the front cover with the diode board. It gets hot and drops to 13.8volts out put.
My diode board mounting plate was made to have it there but I didn't like the 13.8 charging voltage it caused
It was pretty neat because I had only 1 wire for the charging circuit coming out of the front cover :'(
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Whilst I am content to leave the airhead charging system pretty much stock, events in VW world have forced me to investigate alternatives.
The alternator:
VW aircooled Type 4 engines (1700, 1800 & 2000cc) used a hybridised version of the Bosch "universal" 55amp alternator.
The hybridisation consists of:
1 Unique outer housing
2 No fan on shaft
3 A rear cover with orifice to allow blast cooling air bled off from main fain housing
4 Unique diode board to fit in the minimum diameter housing
5 Unique rotor (however oter bosch universal rotors can be made to fit by parting off a small amount the rear end of the rotor shaft
The problem
Rotors NLA (but see above)
Housings NLA (not really a poblem as every VW shop has lots of dead ones
Diode board NLA (which is the major problem).
Commentary
VW / Bosch did briefly market a 70amp alternator to assist those vehicles equipped with a petrol air heater and therefore potentially parked up with heater and fans running. These 70amp alternators are near mythical, Imhave held a dead one in my hands but they have an even longer list of NLA parts than the 55amp.
There are severe space constraints and it is not a practical proposition to fit an alternate alternator, the housing was cunningly designed to fit the available space. A larger diameter could only be accomodated by firstly removing the exhaust system, but the length of any replacement alternator cannot be much more than 10mm longer than stock in order to fit in the available space and take a feed of cooling air. The blast cooling air is essential as the alternator sits only a few millimetres above the exhaust heater boxes.
I have tried abgout a dozen alternatives, the only ones that fit the space, eg Kubota and older Honda Civic, have less output than stock and would requeire custom tine ware to take the cooling air blast at thhe rear of the housing and pass it forward. The Delco alternator from Robinson 44 and 22 helicopters could (I think) be made to fit with a bit of machining on the housing, they have the advantage of being set up to receive blast air cooling from the rear, they are also available in 70/90 amp. The problem with these is that they are a controlled item and the only way I will ever get one without paying $1,200 outright purchase for a new one, or $700 for a time-ex one is to rob one from a wreck before the aviation wreckers get their hands on it. In short - not going to happen.
Solutions
The easiest solution given that the original diodes are simply pressed in, wouldbe to obtain new diodes and replace the failed ones. Easier said than done, not making much progress on that one. Any ideas?
The second easiest solution would be to find a source for replacement diode boards. There is a firm in the Netherlands that claims to have them - Euro 29 for the board is reasonable, but their postage impost of Euro 99 means I will never find out if they are for real. Another firm in Russia claims to have them but they have a minimum 10 buy policy.
Lastly I should mention that you can buy quiite cheaply whole replacement alternators from Poland, these come with no manufacturer details on them whatsoever, they also do not have a stella reputation for reliability. I have fitted one to our Kombi after firstly replacing the bearings with ones that the manufacturer was sufficiently proud of to put their name on. It runs with a 14.2 volt output irregardless of what regulator I fit to it which is a concern. Thinking back to when I had it apart to fit bearings I *think* it may have a regulator module as part of the brush assembly. Needless to say I am not keen to head off on a long trip at the mercy of that alternator.
So, I've reached what I think is the best solution - fit an exernal diode module. What do you think?
One last comment. I the course of hunting a replacement regulator late last year I discovered that the excellent Bosch (Australia) RE-55 and RE-57 regulators are no longer available. I bought an adjustable one from Motobins which I have not used as in the meantime I found these devices from China. Seems to work very well although of course it remains to be seen if they are reliable. The cost was a whole $11 each!
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My first mini had a dynamo. I seem to think one end of the field was always earthed, not positive tied. Alternators only came about due to the silicon diode. Power transistors were available not long after and npn would have been the choice with the a circuit. B circuit maybe coming from the convention of switching positive using a mechanical regulator on a grounded dynamo field, carried over to alternators?
Apologies if I appear argumentative, this stuff interests me, which is why I really enjoyed working on steel mill drives. Magamps and mercury arc rectifiers....
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Re VW: An external diode board should work fine. Saabs kill alternator diodes with regularity too. Probably a design fault rather than heat on these though.
I saw you regulator on the other thread. I can confidently ask now, is it a or b circuit?
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Negative ground is all I know.
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I think this means what you said :2vrolijk_08:
"F" is the battery +.And the other terminal is ground( motor and battery must be connected to the ground together when using).
Yoda translation from mandarin.
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OK this regulator is definitely a BJT type PNP and b circuit for standard airheads.
The volt drop is quite significant and the switching range is baggy, almost like a linear amp around trip voltage. In comparison, the Cargo MOSFET type switched very quickly and did not get warm. This one will get warm and might dither and get warmer still. 1.3+ V is significant when only dealing with 12V, so although very useable with a slightly higher than standard voltage (fine for AGM batteries) I think a home-brew is in order. Of course it depends on what voltage the field coil is designed to saturate.
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I spotted this one before and it appeals to me as a simple / good design. Mosfets superseded, but plenty of alternatives and I have all the other parts in various biscuit tins apart from those :-) The 30 year old caps I found I might pass on and maybe the equally vintage tantalum one... Transistors don't have a sell by date do they? Not like my mums box of 15 year old Assam tea I found? Voyager is still ticking, so I guess not.
http://chemelec.com/Projects/Alternator/Reg-SCH-P-Mosfet.png (http://chemelec.com/Projects/Alternator/Reg-SCH-P-Mosfet.png)
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A cunning plan.... :naughty:
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I have been trying to install a inductive pick up in my beancan to get the full benefits of the HEI ignition module
The winter this year has been too wet and icy so this is keeping me occupied
I am using a pick up coil from a Mitsubishi forklift
Mounting the pick up on the original breaker plate was the easy part
Getting a custom made reluctor to have near perfect timing between the 2 cylinders is proving to be difficult without a proper mill or lathe
All i have is a drill press with a compound slide table on it :furious3:
I have the 2 cylinders firing within 2 degs but I would like to get it it closer
The old Honda CB owners do it with GM Cavalier coils and that is what I am using
http://gpzweb.s3-website-us-east-1.amazonaws.com/Ignition/CBheiModCavCoil.html
But they have it easy because they already have an inductive pick up all they have to do is mount all the parts
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Love it. :tekst-toppie:
Are you have two pick up coils and twin ignition amps and coils then? Oh, no, one coil one pickup and dual reluctors.
The brief bit I read on the HEI is that it retards coil charging at low revs to conserve energy, then advances it as RPMs go up and uses current limit to saturate the coil without burning it. There is a feedback loop in there for that but I didn't think it altered the actual ignition point i.e. so it is just getting the two pickups to trip at exactly 180 apart physically that is the problem? The bean can isn't a great diameter for fine adjustment.
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Just one trigger but 2 lobes on the reluctor
In the screen shot below
The lower trace is the ignition coil primary voltage on the NEG side of the coil
Upper trace is the trigger coil out put
point A is were the dwell starts
point B is where the current limiting of the coil starts (drops voltage to around 4 to 6 volts I think
point C is where the spark occurs
It adjust the dwell according to the amplitude of the trigger coil output
The dwell time is not that critical on a 2 cylinder compared to a 8 cylinder
So as long as I get it to spark at cranking speed I should be okay
I may have to bump up the base time a couple deg because of the slight retarding caused by the dwell lengthening
When I was testing it on the bench with the drill press as a distributor tester the coil stayed cool and the Ign module didn't get hot at all as long as it was clamped to a heat sink
Drill press is the same as a Pillar drill
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Some pics of regulator. I can measure 0V drop across the IRF4905 MOSFET (low RDS of 0.02R) and as expected the switching is very positive with the hysteresis. Voltage looks good, so will fit in the bike. Note higher current on the same bulb test load than the cheap ebay one as the regulator is not dropping any voltage. Doesn't need a heatsink really 3A X 3A X 0.02 = 0.18W.
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It will be interesting see what the charging voltage is at 1100 rpm :lurker:
It has to be better than the stock regulator
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More fun and games. The MOSFET regulator works, but the capacitor values are far too slow for our little alternators. The field collapses when it switches off and then takes a second to get going again. Car alternators (for which this is designed) probably have a much bigger field with more inductance (more iron basically) which will tend to hold up between switch points. I will pull the 100uF and 10uF and put (say) 1uF and 100nF.
Anyhow, now the original part is off the bike, I've tested it. It goes off around 14.25V and back on at 14.05V. The transition is linear-ish due to the BJT output. That is similar (but not as slow) as the cheap Ebay type. However it does only drop 0.7V when fully on which is expected and good.
It's pretty easy to put a MOSFET output stage in though like this (see pics). The Darlington pair of BC327 and BD244 is removed, the base (now gate) resistor of the MOSFET increased to 2K7 and where the base and collector of the BC327 linked out. This works in the same way as the original (+-) but has no drop when the FET is switched fully on.
Pics.
When the BJT is off, the FET sees -9V which is plenty to turn it on.When the BJT turns on, the FET sees near full voltage which turns it off.
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The 100uF cap replaced with 100nF and the 10uF with 10nF. With the hysteresis and looking at the (basically speed-up and RF filter) caps in the Darlington BMW design I hope this is fast enough! I love the smell of burning fresh epoxy-on-soldering-iron in the morning :flamethrowingsmiley: I like that one, so here's another :flamethrowingsmiley:
[This all counts a Continuous Personal Development I suppose. Plus what else would I do on a Monday night during an increasingly annoying pandemic!]
https://youtu.be/Qu5bRDmlrbI (https://youtu.be/Qu5bRDmlrbI)
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The smaller caps worked and she keeps the fire lit on the stator without dropping out now. Idle voltage and 2,000RPM volts about the same as they were (12.5 and 13.8 on my USB socket voltmeter), but the engine is stone cold and I'll see once it warms up. After measuring the standard regulator, I'm not expecting huge changes. Like the loss of 1 gramme on the hummingbird (size) of the alternator, it might make a difference. I'll also put the DVM on the battery itself to see what is going on there.
It went from -3 to +10C today and the difference in starting performance is immense. Cold, thick oil, high compression and cold battery.
The standard electronic regulator design is obviously spot on and with a tweak of the pot can be upped a little for AGM batteries. Changing the BJT output devices to a modern enhancement mode P channel MOSFET is also extremely simple and functional. The IRF4905 is rated 74A /260A pulse vs the BD244 6A /10A in the same package. What a difference 40 years makes.
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I stared my R65 at 19F deg
When I first hit the button the motor would not turn over
I thought maybe I hyd locked it because I left the fuel turned on
So I turned the motor over a couple times by hand and I hit the start button again and it turned over and started
It was probably not a good idea to start it at that temperature
Some times the oil filter can collapse because of the thick oil
It is synthetic so it's probably OK
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A run around the town tonight and the alternator is behaving exactly as per the original BMW part. The local motorists are also behaving as they usually do, good, bad, hopeless and arrogant :Kick: Yes I know your 5L Mercedes does 200 MPH, but I can nip off from the lights faster than you. It's a bike, live with that! Going past me at 70 in a 30 a few seconds later is not going to change that or make me ride unsafely. On you go, have a good evening.... Destination F.
Conclusion: The original part is obviously tuned to the somewhat puny alternator. i.e fast response to keep the field on the boil. If the device has failed, than an easy swap is to a modern MOSFET which should last forever and then some. Otherwise (apart from maybe tweaking the voltage up a tad on the pot to match modern AGM batteries) leave alone :dankk2: