Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: bigmockuk on August 04, 2017, 02:10:06 PM
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Im Thinking the alernator coil windings have shorted out,wondered if anyone can confirm this.ive did a continuity test between all 3 yellow wires and that appears ok however theres also continuity between any 3 and earth.ive had a close look and altho they look fine the internal windings could be shorted out.ive read there should be nothing between these wires and earth.
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If it has its the first one I ever heard of, make sure you have your meter set on Megohms for lead to earth but on milliohms for lead to lead. Check where the leads go from harness all way to coil as they can get trapped in several places
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I had two 400/4 stators do exactly that. It's maybe because on the 400/4 and the 500/550/4 they don't run in the oil (unlike the 750 and early Honda twins). There should be infinite resistance (or megOhms) between the steel frame and any one of the three yellow coil wires, assuming that your have disconnected all all three yellow wires from the loom. Another possibility is that the insulation over the 'star' point (i.e where one end each coil is commoned together and crimped and soldered) has been damaged causing the connection point to touch the steel frame . If it's the latter it's a relatively easy fix if not then you will probably need a rewind or cheaper a replacement used one. Just my 2p worth.
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Hi Bryanj not sure what the diff settings are on this mutimeter its just a cheap meter ive had for yrs.the ohm settings say like 20/200/etc.when i touch both probes together i get a reading and when i touch any yellow wire and earth i get a reading.ive taken the alternator cover off and taken out the rotor to inspect the windings which to me all look rigid and nothing indicating anything could touch any metal.i was thinking is it possible with all the yrs of use and the heat involved would it be ossible for the coating to break down inside the rotor where the winding pass thru?
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hi Ashimoto you say you came across the same problem? wa that maybe due to yrs of heat breaking down the coating and allowing the wire to touch metal?
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Only ever seen em short after accident damage, you need to check at all solder/connection points
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Bryan you mentioned earlier to make sure i was using lead to lead ohm and not lead to earth,excuse my lack of knowledge here but would the wrong meter setting actually give a reading between the yellows and earth in that case
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this is the meter i used and set at 20k ohms
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Yes possibly, on that meter the picture shows it set on volts, if the knob is rotated anti clockwise the next section is Ohms the first setting is the highest setting (Mohms) and with the probes together a reading of zero is expected whilst apart there should be no reading showing (infinite) the yellow to steel core should be infinite, if you get any reading turn the knob anti clockwise until you get an exact number and report the number and scale
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hi Ashimoto you say you came across the same problem? wa that maybe due to yrs of heat breaking down the coating and allowing the wire to touch metal?
Yes it was breakdown of the lacquer insulation on the winding wire and subsequent corrosion. One was on my original 400/4 I bought in 1977 and happened after about 15k miles and the other was on my current 400/4 and was like that when I bought it in 1985. Both bikes had never been accident damaged and the stator covers had no scuff marks etc. I still have the old faulty one from my present bike and when I find it I will photo the area in question and show the resistance readings. To measure the winding resistances you need a quality multimeter with 100 Ohms range as the value is sub 1 Ohm.
Don't want to get too techie though 'cos some people just have a pop at me on here when I do it :(!
If you need any more info PM me or phone me 07515121226
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cheers for the info on the meter bryan,i`ll be up the garage the whole day today as got tank to spray and side panels to rub down n prime.i`ll do that test and take some pics and report back later tonight when i get in.
@Ash,ye the reason im thinking along the lines of insulation breaking down is that since ive had the bike runningi it gets pretty dam hot! im talking not being able to put your hand against the alternator housing any longer than a few secs! so would not be surprised if insulation did melt.would be interesting to know the temp at what that would happen,but strange how yourself bryan has never came across it on this type of bike assuming it has happened? hopefully find out by the end of the day! cheers guys
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Its a varnish type insulation so has to be at damn near melting point to burn off and these motors do get hot
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Common temperature classes are 105 °C, 130 °C, 155 °C, 180 °C and 220 °C. However, I suspect 60's/70's varnish is around 160 ->180 °C
I have heard of 'weather seized' 500/550 engines being due to water ingress in the alternator housing and corrosion between rotor and stator (ask JamesH). You may be lucky it may be something else but I was amazed when two 400/4 stators went bad as all of the other Honda'a I had owned and 750 stators I have fixed have never suffered that problem (all ran in oil). One stator was 3 years old and the other, so not an age related thing really. One common factor though was I always fitted a Cibie (convex lens type) headlamp to my 400/4's back then and not sure what power they pulled c/w standard feeble effort.
I just rewound a (600 watts) Harley Davidson 50A 12 stator/PM rare-earth rotor using PEEK insulated magnet wire for a job at work. We cranked it up and safely pulled 1250 watts out of it at 3k rpm :) ( now kicks out 250v At 5A due to more turns of thinner wire).
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Anorak alert!
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My new Tiger 800 (picked up today) has an uprated (650W) alternator.
What's the 500?
160W?
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Nicely worked in that Steve. How is the new Tiger. Cracking bikes.
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Anorak alert!
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Don't you jump on the bandwagon too Steve ;) !! I get PM's from members on here who actually appreciate the techie content that's why i came back here after a very offensive and personal PM someone sent me last year. My advice to folk who don't like the 'anorak techie' content is ignore it and don't read it if it offends you.
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That was an interestig point about water ingress and corrosion,this bike lay garaged for over 25yrs and when i stripped alternator it was all dry just some light corrosion.the battery had been removed at time of storage.in fact i still chat to previous owner it might be worth asking if he had issues with charging system.I set the multimeter to what Bryan had said,2000k and it initially read "1" .Then on first contact with either yellow wire the scale jumps about then settles at -0.00.it does this between any yellow wire and earth too.still to take pics.the windings are very firm and no obvious signs of melting.the "star" point looks bare but not near anything.I tapped up the 3 loose ends of the wires where they leave the windings as they looked like they were touching each other and bare too.you would think looking at the temps you gave Ash that the wires should not melt?
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I'd love to get an updated alternator on my cb500. I have one at least out of about 6 that is a dud, though beyond a basic visual inspection that showed no obvious issues I never did a proper diagnosis of its faults. Swapping it out cured the bikes charging, accidentaĺly 're fitting it caused them to return so failure ain't unknown but not that common given the age of the bikes.
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Anorak alert!
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Don't you jump on the bandwagon too Steve ;) !! I get PM's from members on here who actually appreciate the techie content that's why i came back here after a very offensive and personal PM someone sent me last year. My advice to folk who don't like the 'anorak techie' content is ignore it and don't read it if it offends you.
Could do with a bit of techie advice on my thread about the LED bulbs Ash if you have a minute. Cheers.
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Anorak alert!
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Don't you jump on the bandwagon too Steve ;) !! I get PM's from members on here who actually appreciate the techie content that's why i came back here after a very offensive and personal PM someone sent me last year. My advice to folk who don't like the 'anorak techie' content is ignore it and don't read it if it offends you.
Ash.you continue. Your information is
Always worth reading
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Ash, I also love to read your techy contributions. Absolutely do keep making them, if nothing else it helps us understand why cheap #### parts fail, and often it gives me an insight into how I might repair parts that are otherwise beyond economic repair, and the future of old bikes where parts are no longer made relies on owners keeping these bits to repair in the future if not right away.
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+1. Keep he techie stuff coming. Been very useful to me.
Mostly packed up full time work and miss the technical input from there and the cleaning/turning/materials/chemicals...
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OK I will keep them coming but I will try to include techie stuff in 'Anorak's corner' and not enter in the day-day general discussions on here that, often, merely cover old ground and could be answered by using the excellent search facility on this site (unlike the USA one that's gone t*ts up and you have to use Google's search) or available in the Dropbox Honda manuals I put on here. All I am trying to do with the techie stuff is lift the profile of this site so that's it's the 'go-to' forum for SOHC bikes in the UK and not just an 'also-ran' and hopefully discourage people from migrating to the likes of Facebook (as a couple of well respected members on here have already done). Due to copyrite laws, other sites have had manuals etc available to download but subsequently have had to remove them and therefore you can't rely on them still being available just when you need them...that's why I used almost all of my free Dropbox space to host some manuals, which hopefully takes the onus off Steve. Likewise there are always spats on here about pattern parts, complicated by the fact that the likes of DS won't give you tech details. This is why, when I have time, I will get the 'experts' I know, though my work, to analyse or measure the parts and then there is no argument or build test gear to do it myself to do this. For example if you get a pattern rubber item that's exposed to oil or fuel then a basic analysis will reveal if the material used was fit for purpose. This all takes time and effort though but once it's done it's done, published on here then hopefully there for the newbie guys coming along.
I think people sometimes have a pop at me on here because, presently, I don't have any of my bikes on the road. I have personal/medical reasons why I don't ride at the moment but hopefully this will be resolved in time for me getting my CB500K0 finished (I have all of the parts for it now so no excuses :D ) . However, quite frankly, my personal situation/mental health is nobody's business on here. I am lucky to be here anyway 'cos I used to go to work every day on my 400/4's from 1977 to 1994 and my boss at the time informed me that, statistically, I was dead 17 times over .... he was nicknames 'Dr. Death' by everyone who knew him though as he looked like Christopher Lee after a bad night out :) .... he definitely did have a very ghoulish persona about him. Absolutely brilliant guy though ..worked at Harwell in WW2 until the Yanks purloined his heavy water.
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Any of you guys happen to have a spare for sale that works? i contacted westcountry windings on sat and their looking at £125 to have the windings redone.
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Any of you guys happen to have a spare for sale that works? i contacted westcountry windings on sat and their looking at £125 to have the windings redone.
Sorry can't help personally ...there seems to be a lack of them for sale on eBay which makes me think they do fail ... Best bet IMHO is to call DK referring to this ended sale below and see if they will price match on another one if they have one ...even though they don't take electrical stuff back if it's found to duff they have always been very reasonable with me. Those 70's Honda stators are very hard to rewind ...hence the high price. Later ones that use permanent magnet 3-phase are much easier to rewind/repair.
http://www.ebay.co.uk/itm/Honda-CB500-4-CB550F-Four-1972-1977-Generator-Stator-Windings-Field-Coil-/352036992297?hash=item51f70a3529:g:6KAAAOSw5UZY-0-w
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There's one in this lot that I put on eBay. I have to many watchers to take it off!
http://www.ebay.co.uk/itm/282596988676?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649
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Just went and looked at it and there is rust on it, I don't know if it would work but there is still magnatisum in it.
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have you had any time to run a meter across it to see if it has shorted or that
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I would not know how to do it I have a low tech draper meter but would not know what to set it too
If you talk me through it I could check it.
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I just had a really good look at it and there are several broken wires on the winding at the join with the output wires. So I would say it's kaput.
Sorry I can't help you out with it. Clive
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Hi As far as i know you have the three yellow wires coming from the rotor and a simple continuity test would show all 3 are connected (which they are at each of the other end of the wire in the windings) a meter set to show a reading when both probes are touched together should show the exact same reading if any two of the 3 yellow wires are touched with the probes but there should not be any reading if one probe is placed on the metal body which carries the windings and any/all 3 yellow wires.if you were to place a probe on the metal body and the other probe on a yellow wire and it showed a reading then there is a short circuit which is not good which is what is happening to my own.hope this helps?
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I don't suppose the 400 alternators are the same?
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nope smaller
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Just thought i would share my findings here.New coils arrived along with new all-in-one rectifier/regulator so thought i would try it all out.First off i found that the existing rectifier that should have had a connector-conector had been removed and all wires from that were bared/joined together!so new conectors are needed there but in the meantime ive fitted spades and taped up.i tested the battery before startup and it read 11.70 volts,after startup it read 11.30 volts and no amount of revs changed that.i took a reading at the black wire for the regulator and find its slightly less than that of the battery by half a volt.connecting that to the new rect/reg unit and nothing comes from the white wire.i put the black back onto the original reg still on the bike and get a reading of 10.70 from the white wire terminal so connected white wire to original reg and am now reading 12.3 volts across the battery at 2000rpm.so although i first read a short in the alternator,its charging using new rectifier and old regulator! any thoughts welcome...should i run it with new rect/old reg? the new unit came from ebay and stated it was for the 550 four