Another Starting Problem. Please Help!!!

Had starting trouble since i got the bike, i have done all the checks on the charging system and all the figures seem to be as suggested on this site and in the haynes manual (its a w reg sv650s by the way). The only one that is not right is when i measure the voltage accross the battery with the engine runing and the lights on then rev it to 5000rpm the voltage drops from 13.3V to 12.1V when i let off the revs it rises back to around 13.3V. I have put a brand new fully charged battery on and it still does this same.

Last night wouldn't start (before new battery and it had been on the optimiser for 24 hrs) managed to bump it and then went for a 25 mile ride. At around 20 miles i noticed the dash lights flashing with the indicators i pulled over to investigate and the bike cut out upon stopping, it wouldn't bump and had to get a mate out with a car and some jump leads (hence new battery today)

Put the new battery on tonight and it started first time. Has anyone any ideas what is going on with my bike. I am at the stage where i am getting really P****d off with it and conisidering getting rid. I dont want to do this cause i love the bike (when it works). Is there any fool proof tests to see if it is the reg/rec or the alternator that is at fault. Or should i just shell out for a new reg/rec and a alternator.

Please any help or ideas is greatly received as i am at my whits end.

Cheers in advance
Andy

If it pumps out 13.3 at idle, then we can assume for now that the alternator is good. I am not surprised that the voltage drops when you rev it as that is what happens to mine too!!! But not right down to 12.1v!! Think it is only 12.5 ish though which I think is naff!! ... I have swapped reg-rec units from one of my other bikes and it is exactly the same - so unless just plain unlucky and have two snotters acting exactly the same, I figure this is the norm? Or at least not the RR's fault

When your bike refuses to start what is the battery voltage???

Problems like this are often down to bad earths. These sort of things only fail under load - so although they might check out with a multimeter, put some load across the circuit and things start to struggle ...

Originally Posted by Blue_SV650S

When your bike refuses to start what is the battery voltage???

The reading is between 11.5v and 12.1v depending on how long its been left.

I hope the new battery has sorted the problem. I had to put the bike on charge every night and leave it on untill the next time i used it or it just wouldn't start and the battery would read as above. My mate says the battery needs to be at least 12.3v to start but even 12.3v would be very lucky to start the bike.

I need to sort it one way or the other as i am scared of going any serious distance away from home because if it does conk out and not start i would be stuck.

Did you check the fuses? Is the bike alarmed?

It could be a chafed wire. I had something similar on my K2, had to remove all the panels and look for damage in the loom. In my case it was kind of easy to spot because it was chafing against the rear sub-frame and caused some visible arcing when trying to start the bike.

[Spanner Man]

Morning all.
Check the output voltage of the rec/reg on the red output wire if you get 14+ volts consistently, the fault lies within the circuit, or another component.
If you're certain that neither the battery or the rec/reg are at fault. Run another earth strap directly from the negative battery terminal to the frame. For as Blue points out a bad earth could give you this symptom. The Japs have a habit of running the earth strap to the engine, therefore the battery earths via the engine mounting bolts, which is ok when the bolts are new, but a few years corrosion on the bolts will soon put paid to that.

One item often overlooked when diagnosing charging faults is the starter solenoid, these can be tested, but as with all charging faults substitution is really the only way to be sure.

Cheers.

This may be pointless but mine is the opposite, it shoots up to over 16 when i send revs through It is the regulator that is the prob for me.

[Spanner Man]

Morning all.
Duff regulators can go either way, too much or sod all.
Did you get the new one I sent you Plowsie?

Cheers.

Originally Posted by Spanner Man

Morning all.
Duff regulators can go either way, too much or sod all.
Did you get the new one I sent you Plowsie?

Cheers.

Got here yesterday mate, sorry i forgot to let you know

[Spanner Man]

Jolly good show. At least the Post Office can get it right sometimes

Cheers.

Originally Posted by Raf

Did you check the fuses? Is the bike alarmed?

It could be a chafed wire. I had something similar on my K2, had to remove all the panels and look for damage in the loom. In my case it was kind of easy to spot because it was chafing against the rear sub-frame and caused some visible arcing when trying to start the bike.

Which fuses? Yeah my bike is alarmed with a datatool veto evo.

going out on it in an hour. new battery in. not been on charge all nite and day. will post results of new battery.