question about measuring alternator/ stator resistance

[fishtail]

Apparently the RegRec of CRM250AR (SH572B-11) can be replaced with Regulator Rectifier of Honda CG125 (SH572LB) - all you need to do is replace generator side connector (3 yellow wires).

Tip form Dirlewanger .

thanks dude! would you think that works for a mark 3?

[knackeredMk1]

Unfortunately not as the AR uses 14.?v and the others use 12v. I would try to find a Mk3 reg/rec but you could possibly use a Mk1/2 version but you would have to change the connectors and the wire length.

[fishtail]

search will be expanded thanks!

connector no problem - was melted to hell so it is no more... I will probably just solder the wires together and put some shrink wrap over each one?

[kernow crusty]

Hi fishtail,
going back to measuring your stator resistance, you hit upon the problem when you said joining the wires of your test meter together gave you a reading of 0.9ohms....
Unfortunately, to accurately read low resistances, like stator wiring, you do need a special, low ohm test meter. Even an expensive ordinary test meter will not give accurate readings for low resistance readings.
A cheaper test meter will just give plain inaccurate readings...sorry!
The reason the value is so low is that you are just reading the resistance of a long piece of wire, one that happens to be wound round and round an armature.....to be honest, faulty stator wires are either OK (low resistance) or burnt out and open circuit (no reading or very high).
Anyway, sounds like you have found the problem.
Regards kc

[fishtail]

alas not!

in a nut shell- this is what has gone on in the last couple of months.. ( or how to feck your electrical system up ) ( hind sight is an education! everything seem clearer )

stupidly connected all the bulbs on my aftermarket headlight.. ( probably 70- 85 watt total ) few weeks later in the middle of a long trail miles from civilation the PV appears to fail.., panic to get back - but realise all electrical power has gone! was a real easy fix - wish I had noticed the lights were off out on the trial.- cos it was a molten connector block - remove that and all appears well... ( note to self - put low wattage LED bulbs in and you'll be right! )

rode it a few times after that tho not far ok.. altho it fouled plugs a few times.. decided to rebore and new piston since it needed it! ( off road for like 3 or 4 weeks waiting on piston,, ( order piston first next time!! )

after rebore - went out for a few short rides.. then the lights started to act a bit weird. not coming on immediately.. ( no light on off switch on my bike )

read that lights didnt work with out capacitor... with capacitor disconnected the lights still worked tho,, wierd! ( fast forward to now red wire to cap has no connection to anything I can find -- time to remove loom and unwrap it

decided at this point to read manual..

head light relay check ok as manual prescribed..
power to head lamps... wow - so low ( 5v max at this point )
looked at regulator out put.. wow so low - 5v again..

performed reg/rec as described in manual... seems to pass.... * since found the diode checking procedure.. will have to get a meter that can do this...

checking stator output... was very low with reg/rec connected ( 1v to 5 v ) disconnect r/r and get 10 to 50 volts..

seems to suggest r/r

unfortunately I rushed and plumbed the R/R back in fully each time.. and on starting bike.. no lights then checked an got the same low voltages.... ( question to test - is R/R being burnt out by "bike" - should have started bike but not connect out put of r/r - can checked if that gave good voltage.. ) low voltage ( max 6 volts ) is measured whether the R/R DC out is connected to loom or not..

next move?

find out why cap is not gettin any juice.. ( red wire not connected??! )

could/ would this *zap* R/R in the 20 sec the bike was running?

[kernow crusty]

Hi fishtail,
hmmm, you do have something fishy going on...
Unfortunately my MK 2 is in lots of bits since I decided to get the engine rebuilt, only about 2 years back...the joys of starting your own business.
I have a wiring diagram somewhere I'll refer to. I have to say Id have suspected the rec/reg too. The stator sounds OK if you are getting 10-50 v ac out of it direct, BUT it is possible that as soon as you load it up, its failing. Can you check the staor volts going into the r/r with just a light load, say the servo and ignition.
From memory, the capacitor is only really there to act as a smoothing device to keep the volts even and without too much ripple. Ive not tried, but Id have thought the system should work without it connected. It should sit across the regulated volts, i.e. one lead to positive and one to negative. Also, have you dropped the stator cover off and had a good look at the windings? Id also recommend getting right up close and having a good sniff. Sounds odd, but the stator should show no signs of black crispy bits and no hint of acrid burnt insulation...
Regards kc

[fishtail]

hey thanks for that Krusty,..

but I'm gonna have to weigh in on the opposite - and say that the capacitor not being well connected was a contributary factor.

I had a combination of troubles and co-incidence..

a cable from the RR that was melted and shorting,,

but complicatin the matter was the crushed cables leading to the capacitor - I think I was wiggling the loom so many times trying to find the faults somethin gave up inside there... didnt spot it straight away but a part of the loom had got "nipped" actually since I got the bike the horn had been a bit quiet.. and after all this the horn is really loud now so thats a result! ie this bike had some additional existing problems...

the connections I will check nex time on electrical issues,, red wire from RR should have continuity to cap and ignition switch. thats the main line!
after that there is a connector block leading up to the LHS switches.. thats another key point,, it also has the 5A fuse..

[fishtail]

the weird thing was when it first started actin weird.. I thought it was the light switch actng dodgy... and the lights did work with out the capacitor... but this was as the RR connector blocks were melting.....

but after fixing all that up the lights wouldnt work at all without the cap being connected... and it was that confusion which made me blow cash on a new RR which I dont really need. cos its runnin off the old one now?

and the cap wasnt workin since an ancient "nip" on the cable - which had corroded the wire and snapped under wiggling... which was giving me the intermittant faults..

if u have any suggestions on diodes so I can connect a small battery to run a digital speedo I'd be grateful

I've since moved all my lights to LED's ( 4 w and 6 w they are pretty bright- and should give me a bit of spare to charge this battery up.

[kernow crusty]

Ahh, intermittent wires can cause untold problems...sounds like you have several areas of potential trouble for the electrical system. The capacitor randomly making contact isnt good...if its flat it will draw a lot of power to charge itself up, quickly! Not good for the whole system. Without wanting to bore anyone, the capacitor is like a self filling bucket. When its empty, it demands to be full up very quickly. Once it is full, it lets a little 'water' (electric) slop out and then slurps up a little more 'water' from the system to replace the loss. (Very basic explanation).

I noticed the other post regarding your Star Wars display....are you sure thats the droid you are looking for?....sorry, I digress.

Im currently doing something similar, but being Cornish, I found that Gas Gas trials bikes use rebadged Acewell units, so managed to get a Gas Gas unit for a tenner off Fleabay. Im just doing the same, sorting out what will drive what. Yours looks like an Acewell unit, or is it a replica?

Do you think yours needs a constant back up supply to remember its settings? Maybe the case. Id suggest a Cyclon battery cell. These are dry cells but more importantly, they are not fussy about how they are charged. Will sit for months without charge, then not worry about having 14v poked up it when you fire the CRM up. Not sure why you need a diode, unless you are concerned about the battery feeding back into the whole system when the bike is not running and going flat quickly...this is possible. A 1n4010 series diode is fine....they come as volts rated and current rated. Get one rated up to 100v and Id say a 10amp current rating. Should cost about 50p, max.

Regards kc

[fishtail]

awesome KC..

thanks for advice on the battery!

so I guess I would wire R2D2 directly to the battery? then feed a parallel from after the ignition switch to get juice to charge the battery.. ( can try putting the diode between here ) or u think the switch will stop the battery leaking into the system?

how u wiring the rev counter? I dont really need it - but since its there...... probably taking a parallel to the coil LT wire.. or is there a feed from the ECU ( saw int he manual a couple of mentions of simply connect a rev counter.... mind u that was the AR manual I think....

which part of cornwall BTW? I spent some time in the 80's living in Torpoint. loved that region!