550 four k3 alternator rotor coils

[bigmockuk]

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.

[Bryanj]

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

[AshimotoK0]

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.

[bigmockuk]

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?

[bigmockuk]

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?

[Bryanj]

Only ever seen em short after accident damage, you need to check at all solder/connection points

[bigmockuk]

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

[bigmockuk]

this is the meter i used and set at 20k ohms

[Bryanj]

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

[AshimotoK0]

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

[bigmockuk]

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

[Bryanj]

Its a varnish type insulation so has to be at damn near melting point to burn off and these motors do get hot

[AshimotoK0]

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).

[SteveD CB500K0]

Anorak alert!


Sent from my iPhone using Tapatalk

[SteveD CB500K0]

My new Tiger 800 (picked up today) has an uprated (650W) alternator.
What's the 500?
160W?


Sent from my iPhone using Tapatalk