Airhead "Tips and Tricks"

That would be the most valid measurement. The forward portion of the rear boot fits over an oval opening in the swingarm.

Forgot about Pi or is it Pie? Sorry learned about that in the 70's in a haze of blue smoke. Ha learned, thats funny didn't learn shit.

It is Pi. Although the Greek letter is more correct. 3.141592653 is about the max I can remember even with short term memory. I meet a young fella once that recited Pi to 40 digits for me. He said he hadn't done it in several years but if he brushed up a little could probably do 80 or more. I listened very intently and then pronounced every digit correct.

The ancient Hebrew/Egyption Royal cubit in inches as determined by Newton=20.612.

A primary ancient geometric construction is 3 to the 8th power = 6561.

20612/6561=Pi

Linking the ancient cubit to the English inch to an accuracy for Pi not exceeded prior to NASA.

The level of intelligent beings never fail to amaze me on this forum.

Very true, but the individual that seeks out Kant as reading material at least deserves the credit for attempting to understand.

I have a couple of Kant books on the shelf. Have never even tried to read them. They are decoration.

About 2 pages of Kant was enough for me.The info on Pi I gave requires no more than compass and straight edge to demonstrate and a bit of grade school algebra to comprehend fully, though it was the result of several decades of research and study of metrology ancient and modern. Nothing at all like metaphysics which is crawling with a few charlatans, not unlike this forum.

So on the HD boards, can they even spell Kant? Always something with you Airhead folk!

Heidegger?

Maybe, but they definitely will know how to spell the word that sounds the same, if properly pronounced, in it's native tongue.

OK, going full tweed 'n' elbow patches here. Dated a gal once who found the origins of that word empowering. Auf Deutsch, koennen: to know.

phantom carb flooding problems are no fun at all :eek1

when new Bings are very reliable and virtually trouble free. but fast forward 30+ years .. all moving components do wear, this very much includes needle, seat and float.

looking at the needle and seat does little good. there's three wear points on a needle: tip, sides and spring gets weak. the seat has two wear points: sides and actual seat. the float can get soaked with fuel and not be as buoyant.

the tiny micro spring limits pressure on needle so tip to seat contact has to be almost perfect. sides of needle can wear into sides of seat .. adding friction just enough to prevent needle from seating.



you could have filtration issues due condition of screen over petcock. then add float height adjustment problems.

to return to new condition .. one needs to replace with new: float, needle, seat, float roll pin, new filter screen or inline filters, new 7 mm lines and adjust to factory spec's.

before replacing seat .. take a cotton swab on a wooden stick .. add chrome polishing compound, then spin inside seat. this will clean off any old film. most times cleaning seat, replacing new needle with new float set to correct height will solve phantom leak problems. using anything but cotton with polishing compound, like a metal drill will destroy seat.


hope you don't need this info ...
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Leaky Bing carb fix on R80 G/S ... tried everything else without success.
it was time to replace the seat. removing seat by carefully following below method requires no heat.

unfortunately bing carbs uses a spring loaded needle/seat combo. this means pressure needed to operate needle/seat is limited to spring tension. viton tip helps in sealing but needle/seat combo pretty much has to be near perfect to work under micro-gram pressures.

above is assuming you've already done the basics like clearing any crud between needle/seat ...
if after replacing needle and setting float at correct levels doesn't work. up next is cotton que tip loaded with polishing compound on seat. if that doesn't work you've got to replace seat in a bing with risks of destroying your carb.

this tutorial gives step by step instructions, reduces risk of damaging bing carb when replacing seat.

use a 24 - 5/16 tap then screw same pitch bolt into now threaded brass seat.
use a nut with ID larger than seat for a spacer. then simply turn nut to pull out.





easy does it when making initial pull. taking apart several times to inspect pull is coming out straight.



use a brass drift to gently tap new seat in



correct float height setting. float level with edge of bowl.



take extra care when cleaning seat .. use cotton swab with carb cleaner followed by chrome polishing compound. which is specially designed to desolve gas crud. don't use any tool harder than brass or you could damage seat.

since float needle is spring loaded, pressure at seat is limited to pressure allowed by spring. ie not much, so union between viton tip and seat has to be almost perfect to seal.



float needle is viton tipped and spring loaded to limit pressure against seat.

How to test Beancan Hall Sensor Module ..

since I've not been able to find instructions anywhere for actual testing of Hall sensor module with simple instructions and clear pictures. here it is ...

what we are testing is a hall module made up of voltage regulator, trigger circuit and actual Hall sensor.





when magnet passes in front of hall, a signal is generated in millivolts. Fluke 789 process meter is being used. but any precision VOM can be used.

HP regulated power supply putting out about 12v is used to power module. but most any power supply 4.5v to 24V can be used. a 9v battery works fine.

here's a picture showing what wires to test without breaking down beancan.

red (yellow/green) = + ... black (blue) = ground ... green (brown) = signal

after hooking up wires as shown .. rotate beancan shaft, if halls module is working. you will see a millivolt signal for a brief fraction of a second.

intermittent output are the worst ... if you are that deep into beancan .. replace that hall module and be done ... or better yet switch to beancan with points!!!



green & bottom red is from 12v power supply ... middle red and top black is from Fluke 789 set to DC voltage. if halls module is working, a brief milliamp volt signal will show.




when magnet rotates closeby .. millivolt signal is generated sending a signal to ECU which then triggers a spark.

How to Replace a Hall Sensor inside a Beancan

here's how you tear into your Beancan from the top without driving out bottom pin, which is usually really tight.

remove top plate and bearing support. then remove large clip underneath.


remove side cap and disconnect advance springs.


remove two circlips, then remove three side screws. when everything is free. remove entire rotor/halls module as one assembly.


remove plastic plug that fastens wiring


if you don't disconnect springs first. springs will let go but might get stretched.


don't even think about removing thin rotor without a puller. the el cheapo battery terminal puller works perfect. take extra care not to loose tiny locator pin.


this is what you see after rotor is removed


early style has two screws, later has two rivets. someone has been here before me
drill out rivets and attach new Halls module taking care to splice/solder/shrink wrap wires to same length.


reassembly is NOT the same as removal. remove last circlip, separate center shaft from halls plate. service advance weight sparingly with a light high quality oil. then insert center shaft, then attach both springs while you have easy access to springs. otherwise it's almost impossible to reattach springs from tiny side cover hole.


next insert hall module plate, carefully aligning up with three screw holes. this pic is shown with old sensor.


replace rotor and carefully drive locator pin with a pin punch.


replace both circlips


install top large circlip and outer cap ... use a tiny dab of grease when installing top bearing plate.


Fin ..

How to test an AGM Battery

1. remove AGM from bike and/or charge in place with cables removed.

2. use a normal size PB charger without desulfate mode, then charge to full. (don't use battery tender type trickle charger which can take several days to charge to full). don't exceed 14.8v for AGM

3. allow AGM to rest overnight after full charge. then measure resting voltage.

4. resting voltage should be 12.6v to 12.8v fully charged. if say your AGM resting measures 12.8v, then starts your bike strong for load test. odds are your AGM is good.

note there's variation for resting full charge voltage. some AGM could read slightly higher than 12.8v resting.

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How to test a LiFePO4 battery (draft version subjective to revision)

1. remove LiFePO4 from bike and/or charge in place with cables removed.

2. use a normal size PB charger without desulfate mode, then charge to full. (don't use battery tender type trickle charger which can take several days to charge to full). don't exceed 14.6v for LiFePO4. ALL PB battery chargers without desulfate mode will charge ALL 12v LiFePO4 batteries. LiFePO4 likes .5C during bulk charge phase. don't leave std PB charger attached to LiFePO4 after full charge (14.6v) is reached. (C = AH)

3. allow LiFePO4 to rest overnight after full charge. then measure resting voltage.

4. resting voltage should be 14.25v range fully charged for batteries without BMS. with BMS voltage will typically be 13.85v range resting.

if say your LiFePO4 resting measures at least 13.3v (90%) or higher, then starts your bike strong for load test. odds are your LiFePO4 is good.

note there's variation for resting full charge voltage depending on what type BMS is installed if any. 13.3v (90%) is the desired resting voltage before starting motorcycle

===============

here's quick visual on state of charge for AGM, Gel, FLA and LiFePO4 .. all you really need is an accurate volt meter and this pic.
if one doesn't have access to a known to be correct meter. Optimate tester below sure is handy to have.



[click to show pic]

Checking DC Voltage Calibration for your Meter

here's how calibration is checked. first one must have a meter worth going to trouble of calibrating. sorry $10 meters don't make the bar.

first method is with a calibration standard which puts out user selected values. meter being tested should read same. since most folks don't have access to a calibration standard. go to second method.

reason I go to this much trouble is to insure any hard data posted by me are dead nuts reliable . that anyone can duplicate with lab grade instruments.

here Martel MC-1000 puts out 3.244v .. Fluke 189 reads 3.2439v


second way is to use a primary lithium cell like CR123 which puts out a stable voltage.. 3.22v with a new Fluke 87V which has recently calibrated by Fluke. go to any HVAC store and borrow their meter



compared to Fluke 789 which also puts out 3.22v .. so conclusion is Fluke 789 is within calibration for DC volts.

here's basically a tutorial complete with clear pictures and detailed information on how to rebuild an .. here ..

most of the gotchas are covered:

how to tell if your master cylinder is rebuildable
how to source washer under brake fluid tank that doesn't come with kit
how to bleed and adjust cable
how to repair brake fluid damage to frame
how to source front brake flex lines that fit exactly like OEM for cheap







here's the correct EPDM Orings for Tank to Cylinder.
then for a backup I've got EPDM flat material in 1/16in and 1/8in to custom cut out flat washers to match original equipment seals. edit: to do flat washers correctly needs .1015in EPDM flat stock.

going to run the two EPDM orings below first. then if that doesn't hold. will custom cut out flat washer seals like OEM. first preference to come up with a solution easily duplicated anywhere.

go to any O ring supplier and ask for:

EPDM 2-106
EPDM 2-111

picture below show flat seal punched out with common leather punch using 1/8in EDPM flat stock.
note seal is not round, but that's not critical, like flat surface. advantage of this type seal is larger surface area. it's really hard to punch out a perfect seal.

after fitting both custom cut 1/8in EPDM seals and stock EPDM .1015 seals.
above two stock orings seal better due to correct thickness.

this picture shows the clear winner. we'll see how it how after a few months.









it's hard to tell thickness between custom cut gasket punched from 1/8in EPDM
gap is too large ... it would probably work, but seal is suspect.



this is using EDPM orings .1015 in thickness, much better fit!
only better seal is if 3/16 EPDM flat stock is available.

How to Test Airhead Diode Board, Rotor, Stator, AGM battery and how an alternator works briefly covered

airhead alternators works identical to automotive alternators. main difference is location of rectifier separate from inside next to stator. this design needs additional wires making connection from stator to diode board and grounds.

lots of folks have logged in hundred of thousands of miles on this system. so it's a very robust system. but fast forward 30+ years .. those wires due to number of heat cycles start to fail. connections corrode with resistance creeping in. hard brittle wires can result from wires actually heating up and/or normal heat cycles after many years. new wiring sets are cheap at $16 from Euromotoelectric .. replace those wires.

above results in lower charging voltages responsible for sluggish charging performance. which a lot of folks mistake for lack of output or wattage (280 watts @ 14.2v = 19.7 amps) . so folks replace perfectly good charging systems in favor of less desirable permanent magnet charging systems.

Warin has posted a number of excellent instructions on how to troubleshoot for voltage drop.

unfortunately when trouble shooting airhead charging issues .. the entire food chain has to be considered. this includes battery, stator, rotor, diode board, wiring, etc. etc.

hence the need for such a complex set of instructions below ... apologies for the complexity, it's simplified much as possible without losing necessary details.

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odds are if you need to test a diode board you've got multiple things going .. tackle one at a time.

you may have killed your AGM battery even if it's brand new .. procedures to test an AGM below ..

for airhead charging systems, most common failure are rotors. stators almost never fail, but it can happen. diode board failures are next. but crispy grounding straps and B+ wires are automatically suspect due to HOT environment under front cover.

full fielding alternator by jumping two flat blades inline on three prong plug will only work if rest of system is working. you need to take all measurements with a known to be correct meter. 7 ohms indicates a good rotor for R75/5 (6.9 ohm) 3.5 ohm range for later airheads (check BMW spec's).. you need to use quality meter like a Fluke. here's calibration procedures.. go to post #896

below is a short tutorial on how to test an airhead diode board .. rotor and stator is briefly covered ... you've got to have a known to be correct meter. . note these are all static tests. what counts is under load. for instance you could have a rotor test say 3.5 ohm (or 6.9 ohm). but fails when rotor heats up under load.

at very bottom of page is how to test diodes if you are fortunately enough to have a high end meter like Fluke 87V with diode test function. but I wanted to show how to test with a basic VOM first.

note below tutorial is a work in progress .. still evolving

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Testing an AGM Battery
How to test an AGM Battery

1. remove AGM from bike and/or charge in place with cables removed.

2. use a normal size PB charger without desulfate mode, then charge to full. (don't use battery tender which can take several days to charge to full). don't exceed 14.8v for AGM

3. allow AGM to rest overnight after full charge. then measure resting voltage.

4. resting voltage should be 12.6v to 12.8v fully charged. if say your AGM resting measures 12.8v, then starts your bike strong for load test. odds are your AGM is good.

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How to test an Airhead Diode Board

this test requires a known to be correct meter. a Fluke 87V recently calibrated by Fluke is used below. set meter to ohm mode then put leads together to test resistance of leads. then follow meter's instruction on how to zero. clamp tips makes test easier to perform.

airhead diode board is a full wave rectifier with two diodes per leg of three phase AC output from stator. as the name alternating current implies .. voltage switches from DC negative to DC positive in cycles per second. speed of rotation and number of north/south poles on stator determines number of cycles.



this airhead rotor measure 3.5 ohm and has 12 north/south poles that generates 12 cycles per rotation. find spec's from BMW for correct ohm reading for your stator.


each phase is 120 degrees apart with all phase independent of each other. diodes are one way solid state devices. installed in pairs with each diode allowing only DC negative or DC positive voltage through.

rotor is not shown for clarity



to test a diode board hook up your meter exactly as shown below. locate all six diode's tip location. each picture will show sequence. note entire board must be isolated. contact from your skin could throw readings off.

locate where diode lead ends up on circuit board on top


a diode is a one-way valve for electricity. Connected one way across the diode, meter should show a very low resistance. Connected in reverse, diode should show a very high resistance.

achieving exact resistance/ohm values in not critical except mated diode needs to be close. if your voltage drop is within about .5v across all three sets (instruction near end of tutorial) .. this indicates your diode board is probably not at fault.

recommendation is to replace all wires possible with below kit .. about $15
a worthy upgrade is a heavy duty diode board for about $69 if diode board tests bad.

common airhead charging problems are related to bad wiring with B+ and grounding straps to diode board. rotor going out is common too... stators almost never go out. but it can happen...

in the process of digging up airhead charging parts for experimentation .. purchased via flea market, three dead complete charging components for airheads. they all were left overs from 450 watt alternator upgrades. rotors, diode boards, voltage regulators and all the wiring ... ALL components except for crispy wiring, tested out still good, if that says anything.

you've got quite a few things to chase down... take one issue at a time.







press tip firmly to break through insulation .. 265.5 kohm


mated pair measures 269.6 kohm


middle bottom diode measures 265.7 kohm


middle top diode measures 264.7 kohm


left bottom diode measures 270.5 kohm


left top diode measures 270.6 kohm


leads are now reversed .. exact same sequence with all six diode showing reading below. verifying voltage is only allowed one direction .. conclusion is all six diodes are good.




burnt diode board show next to a good diode board


testing stator .. make sure no connectivity to ground on all three legs


testing connectivity between legs .. shows .6 ohm .. this is a good stator


How to test diode board with a diode test setting meter.

wanted to do above test first for folks using a meter without diode test function. here's how diode test function works.

diode setting tests a semiconductor junction by sending a current through the junction, then measuring junction's voltage drop. A good silicon junction drops between 0.5 V and 0.8 V. Fluke 87V then beeps to indicate a good diode.

voltage drop of .513v and .513 for top/lower right diodes.. rest of diodes all tested at .5v drop or all good.




most Bosch alternators use the same three flat prong voltage regulator. same for all Bosch internal voltage regulators used in R1150/1200. that regulator with brushes fits almost all Bosch alternator with internal regulator.

the most interesting one goes on Volvo with an adjustable pot to change voltage output.





RE55 with two prongs will not work for airheads with three prongs regulator as a direct drop in.
some early auto bosch alternators did use two prong style regulators

RE57 with three prongs looks like it will work ..



RE55 with two prongs


in a pinch some pretty wild setups has been done to airheads. almost any three phase automotive bridge rectifier can be made to work. which typically are designed to support much larger loads.

one of the best suggestions I've seen is adding beefy ground wires from diode board directly to stator case. car alternators rarely have diode board grounding issues because bridge rectifier are bolted directly to alternator case.





watch this excellent video which is a car alternator but works the same as airhead alternators.

<iframe width="640" height="360" src="//www.youtube.com/embed/-JURAbC6oRE?feature=player_embedded" frameborder="0" allowfullscreen></iframe>

choosing a 450 watt alternator .. Permenant Magnet or Electro Magnet System?

So you think it's time to up grade your airhead's charging system. unless you have specific needs like heated clothing and/or large lights to support. odds are you may be better off repairing your OEM charging system. which typically puts out about 280 watts, some slightly less depending on model.

most airheads with sluggish charging problems are related to low charging voltage, not lack of output. if your charging system is not working at all, please refer to the airhead alternator and/or battery trouble shooting section a few posts back.

electro magnet systems has it's weaknesses and advantages just like permanent magnet systems.

EM vs PM charging systems .. IMHO EM is the superior system and is used almost without exception on ALL the auto's in the world. charging is triggered by demand by controlling voltage going to EM rotor.

brushes wear and need to be check every 50k miles or so. stators seldom go out. .. diode board and rotor are known to go out. all things considered a very rugged system.

I've measured 29 amps @ 14.2v going into EarthX ETX36 (14AH) LiFePO4 at 25f with engine at 3k rpm .. headlights only on. R80G/S has an early motorad electric 400watt system with rewound OEM rotor. advantage is being able to use OEM rotor in case of rotor failure. R80G/S bosch starter would draw 275+ amps at 20f. EarthX ETX36, Shorai LFX36 and 20AH electric bike LiFePO4 all delivered the goods at 20f.

PM charging systems uses a rotor with permanent magnets, stator and rectifier/regulator both can overheat and fail. with the R/R the most common failure point. PM charging system's so called advantage is to put out full output pretty much all the time. it's the rectifier's job to convert AC output into DC, which duplicates diode board. voltage regulator's job is to shunt to ground all the excess output .. ALL the time. this is why a PM charging system R/R gets hot .. along with stator.

one of the most common failures for modern bikes with PM charging systems are failed R/R from overheating. overheated stators failure while not as common are not too far behind. it's a common upgrade to change to MOSFET switched R/R. if you follow the F800/F650 and KTM threads .. R/R failures are fairly common.

airheads are not known for high horsepower .. all that wasted energy is turned into heat. IHMO all this wasted energy just to gain charging at idle is just not worth it. your battery AH if sized correctly will run your airhead on a dead drain for a long time. who cares if your airhead uses more energy than it produces at idle. what really counts is that you put back into battery more AH than you used for the entire ride.

EM charging systems are better suited for LiFePO4 .. if dropping 12+ lb is appealing .. there's an excellent 20AH actual LiFePO4 for airheads for about $130 costs. tested by me down to 20f .. cranks over excellent at low temps. info inside battery testing thread .. link in sig