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DanR82
04-10-15, 07:45 PM
Newbie here so be gentle.

I recently bought a 1999 curvy which had been sat for a little while.
The bike went straight to a mechanic who got it road worthy and through its MOT however it’s got an issue with the electrics which the mechanic never looked at (the bill was already running pretty high) and now I’d like to get it sorted but need some advice.

The issue was first noticed when the lights were on and the bike was rev’d. The lights dimed a little and then came back. I’ve also noticed that when the indicators are on, the dash lights dim as the indicator comes on and off and that’s with lights on and off – not sure if that’s usual.

I’ve checked the voltage across the battery terminals at various set ups and to me it looks as if the battery isn’t being charged when the lights are on. I’ve searched through loads of threads about similar issues and tried a number of the recommendations but I’m still having the issue.

The voltage readings across the battery are all as below and I’ve checked the regulator rectifier abut this gives normal diode readings – I’ve even swapped it for another and there is no change.

The battery is about 4-5 years old but has been on a trickle charge for most of that and seems to run fine.

Battery was fully charged using a trickle charge and then tested 36 hours later. Reading was 12.7V
Lights off:
At idle: 13.4V
2.5k rpm: 13.5V
5k rpm: 13.5V
All seems ok, just.

Lights on:
At Idle: 13.1V
2.5k rpm: 12.6V
5k rpm: 12.6V

I’ve been using the bike without lights and never had a problem, however when I ran the lights for a little while the other day (about 8-10 miles), the bike struggled to tick over the following morning and I only just got it running.

I’ve gone through as many of the connectors as I can around the right hand rear fairing and cleaned them up / added some WD40 and cant see any obvious issues with the cabling anywhere on the bike.

Any advice / recommendations on what else it might be and how to go about fixing it?

Geodude
05-10-15, 07:14 AM
Dont know if you have already but read the fault finding guide guide in my sig and have you tested the three yellow wires coming from the alternator to make sure you have good voltage? again follow my thread for info (click me (http://forums.sv650.org/showthread.php?t=164281&highlight=battery)) from post #10 by yorkie chris for info. Most likely battery is getting a bit old maybe try and borrow a good one from biker pals and try it. HTH as im a bit of a mechtard but im sure the cleverer peeps will be along soon.

Biker Biggles
05-10-15, 07:21 AM
Did you check the alternator output-------the three yellow wires from alternator to reg/rec?You should get about 70+ volts ac from each wire when tested.
Having said that I suspect you have a fault in the wiring lighting circuit.Possibly the switch or the sub loom that goes to the front lights can be subject to chafe.

atassiedevil
05-10-15, 07:48 AM
Also check the earths.
Holy trinity.

Resistance between.
Frame - engine
Engine -battery
battery - frame.

If any of these are above 5 ohms, then that could be causing the issue.
C.

DanR82
05-10-15, 12:29 PM
Thanks for these. I'll check the voltage at the alternator connector (if it ever stops raining).

Geodude, that elec fault finding guide is great thanks. I've seen something similar but will follow this one.

From what I remember, the last owner replaced the wiring loom and ran the bike successfully after but I'll try and chase this through and check for any obvious wear and tear.

I know this is going to be a stupid question so bear with me, but where would I find the earth connection points?

Craig380
05-10-15, 12:40 PM
The main earthing point for the battery negative and the loom is at the back of the gearbox, on the right hand (clutch) side. Shine a torch just in front of where the swingarm spindle locates in the frame: the earth lead is secured by one of the clutch cover bolts.

DanR82
06-10-15, 09:03 PM
OK, so in between the rain I managed to get at the bike. The voltage from the alternator was reading 80+ volts at 5k and around 25 ish at idle so this seems fine.
The earth looks good and solid, albeit covered in crud.

I ran voltage checks on as much as I could and checked the lights again. I'm still noticing the lights dim when the engine is rev'd.
I re-did the diode check on the regulator rectifier and noticed that despite getting 500+ readings before, I now get hardly anything if at all. Same goes for the spare I've borrowed of another bike (not a road worthy bike as its been sat for a while).
I'm starting to think that I've got two dodgy regulators as I've run out of things it could be. But if the regulator was shot, wouldn't this also affect the battery charging system when the lights are off? I only seem to drain the battery with lights on.

Anyone got any other thoughts or suggestions?

DanR82
07-10-15, 06:19 AM
Well the saga continues. Went to use the bike this morning to find a puddle of fuel on the floor towards the front of the engine. Think I'd better deal with that problem first!

johnnyrod
07-10-15, 08:40 AM
Regulator/rectifiers are funny things, and I've seen bikes before where they'll just about run but not with extras like lights. Sounds like the alternator is fine though - the output is right and if there was any continuity to earth it'd fry itself anyway. Check the continuity from the frame etc. to the battery - though, don't make any assumptions. Re. the fuel, a favourite of older bikes is to rust through the tank at the left side near the fuel tap - the lowest point, so any free water ends up there - so if you're struggling to pinpoint it then check that out.