Electrics: where to go?

[franci_c]

Dear everybody.....
I don't know about you, I'm developing a serious allergy to mechanics. Everytime I get in contact with them I feel sick. I have had an electric problem for long time, and after loosing my mind, I decided to take my bike to the garage. I tried a couple, but they filled me with bullsh*t, and I firmly believe they don't know what to do and so start talking nonsense. Is there among you guys anyone who knows somebody in Auckland who can work (I mean, seriously) on an old bike electric problem???
Thanks, folks.

[What?]

So what's the problem?
There's plenty of people here who know enough about electrical stuff to make you wish you'd never asked.
Um, I mean, help out.

[notme]

post a description of the symptoms.....you never know who might reply and tell you exactly what it is.

[franci_c]

Ok guys, it's about a vfr400. Shortly, no spark. In the past I had a problem with the regulator, which was boiling the battery. Pretty common on these bikes. Changed. Everything was fine. The first symptoms were on the track, while I was revving fast there was often a sudden cut (definitely electric), just a fraction of a second, you know what I mean. Then, on the road, the bike stopped. I checked the resistance values between the wires coming out of the alternator, the high power coils also seemed to be ok. Then the bike started again, and worked for a little while. The strange thing, though, is that when I disconnected the battery the engine stopped, while it is supposed to keep running. I guess this is the most important clue, to me is like there's no "right" current coming from the engine, and the bike needed the battery in order to run. BUT, the battery seemed to be under charge, with the engine on, as by reading the V value (around 14). Also, if I disconnect the battery while revving high, the engine keeps running, but in a very irregular way. I bought a new regulator/rectifier. Nothing changed. Then the bike stopped again.Took it to the garage, they told me it's the CDI unit. I had another spare unit I bought thinking that mine was faulty, but they told me that also was faulty. Honestly it sounds dodgy, to me. Ideas?
Thanks for your time, buddies.

[Brian d marge]

I had this real big post all done ,,, then I accidentily deleted it ,,so stuffed if I am writing all that again !

In a nut shell electricity is a lazy sod and if itdoesnt like whats ahead it wont go ( reasons for reg/rec blowing are bad earths and in Honda the connector is not man enough causing a high resistance cx500 goldwings a lot of those early 80s bikes all aflicted )

Electrickery is speed dependent ,,the more you reve the bike the more you make and at a higher pressure to ,,,,So.... if there is a bad earth corroded green wire ,,then at low rpm ,,the smoke ( electrickery ) wont flow ,,or it will but not enough to do any good

So
1 get a wiring diagram
2 get a FULLY CHARGED battery I leave a charger connected
3 Clean ALL the earths in the system ( make sure that All the connectors are clean especially the earth wires ,,you might fins a bluey green corrosion esp on the earth ( green ) wire,,,

now isolate the problem

is it causing ALL the cylinders to cut out or just one , If all then its a component/circuit that effects all , such as sidestand cut out , kill switch , ignition switch , ( speed sensor though memory is vague on these, not sure if they cut out one or all cylinders ) ignition pulser ( isolate it wrm it with a hair dryer then check for leakage to earth and continuity

From what you said , if you spin the engine quickly it will run just ...

but the battery seems undercharged ( starter moter runs slowly )

disconnect the reg/rect there should be 5 ? wires 3 yellow and a red and a green ( or black)
use a 12v bulb inline from yellow wire to earth ( frame ) with battery connected run bike ,,the bulb shoud be bright and when revved look like its going to pop ! v bright " ( check all three yellow wires )

Make sure the connector esp earth is clean if not the smoke wont flow ...

Finally it is a GOOD Battery ?? or the same one that boiled ?

My guess is that its the same one . which has a high internal resistance , this will not let the smoke flow through the battery ( which it needs to do to charge ) and will put a load on the next item down the line ( reg /rect ...and so on down the line alternator ,,,

my GUESS　is that the alt windings are leaking ,,and the alt aint producing enough jungle juice at low rpm ....ie when you put the bulb on the yellow wires ..it will light up but only just more of a yello light rather than a white light !!

Stephen

if you need smoke they do replacement kits

[TLDV8]

The strange thing, though, is that when I disconnected the battery the engine stopped, while it is supposed to keep running.... Also, if I disconnect the battery while revving high, the engine keeps running, but in a very irregular way. I bought a new regulator/rectifier. .


You should probably stop doing the above unless you want to keep buying lots of regulator/rectifiers.Who knows what other damage it does but most electrical systems do not like having the battery disconnected while the engine is running.A magneto might be an exception,but only a guess.

[El Dopa]

Here's a link to a reg/rec faultfinding chart.

http://www.electrosport.com/electrosport_fault_finding.html

I've just replaced the spark plugs on my bike after having a problem similar, but not quite the same as yours. Semms to have done the trick, but I'm intending to spend a bit of time over christmas working through all the stuff
Brian posted up.

[franci_c]

Thanks guys. And Brian, the time you spent rewriting is surely appreciated!
I have to say that: the battery is a brand new one. No "running" measurement can be done since the engine is dead, at the moment, there's no spark. Oh, and the problem affected all 4 cylinders. New plugs also, btw.
And I'd also rule out the hypotesis of sidestand, kill switch, ignition switch and so on. Again, do you think the bike, once started, should keep running even without battery? I know for sure than most do (especially old ones) and I sort of remember than mine did in the past, too. So, when the bike was "working", how come did it turn off when I disconnected the battery? It can't be any switch or any ground, right? But the voltage on the battery terminal was correct, around 14, which means that the battery went under charge, somehow. So, I really suspected that the problem was in the alternator. But why, then, the two garages I went to (including the "Official Honda Shop"...what a bunch of....ass$#@*!) didn't come up with anything than weird things? Anyway, I spent too much time already, I don't even have enough space for playing around, so the best thing for me would be to find some decent human being appointed as a mechanic not just because one morning he woke up and said so. Is there such a rare creature in Auckland, to your knowledge? I thought that also a car electrician, if a good one, could be helpful.

[Motu]

sounds dodgy, to me.
.

Sounds very dodgy to me - someone pulling a battery terminal off while revving the shit out of a bike has possibly done some damage.I don't think you'll find a reputable mechanic or auto sparky who'd go near it.

[franci_c]

so, nobody knows a decent mechanic/electrician in auckland??
cheers

[Motu]

I know heaps...but I don't think they will want to go near your bike....

[Ixion]

Dead pulsar unit?
Could be anything. How do you know the second CDI unit is good? have you tried it on a known running machine? With modern bikes, whether they run (well, badly or at all) with the battery disconnected , is a matter of chance. Some do some don't. But running at high revs without the battery as a sink is a good way to fry a CDI.

Magnetos were a completely different matter. They don't need a battery at all. Long live the Lucas K2F.

[franci_c]

sorry, but what are you talking about?? if you had had a look at an average electric circuit, you would have seen that the current is generated by the engine, goes through a rectifier (because it is coming out alternated) and regulator (to keep it sort of constant despite the change in rpm), and from there is distributed to the rest of the circuit AND to the battery, for recharging...it GOES to the battery. the only time it is COMING from it, is when you make the starter motor running. so, why should disconnecting the battery be of any harm?? the only difference is that the battery is not charged. have you ever seen a gp bike with a battery and an electric starter? or what about heaps of bikes that are similarly born without a battery?
anyway, thanks for your time, guys, i'll figure it out.

[Motu]

I rest my case....