Weird VFR800 Battery problem

[t84]

Took my bike out a couple of days ago after been laid up for about 2 weeks.

Rode about 10 miles, stalled at some traffic lights and bike wouldn't start again, would turn over 'very' slowly at first and then just made a rapid clunking sound from the battery area instead.

I had this problem before I put it into the garage, mechanic said reg/rec was fine and he's put a new battery in as it was flat.

I have a Datatool Veto Evo alarm installed, could this of drained the battery in 2 weeks? And why would it suddenly not start after riding for 10 miles? It turned over fine initally and 10 miles should be enough to get charge in it for another start, no?

Thanks!

[Hooli]

that does rather sound like a failure to charge to me.

[t84]

Surely the bike should cut out then? It's fuel injected, and the lights were bright and strong at all times... :/

[Momentofmadness]

Hooli said:

that does rather sound like a failure to charge to me.

+1 After 10 miles, I'd have expected it to start again rather than run out of sparks

[Hooli]

t84 said:

Surely the bike should cut out then? It's fuel injected, and the lights were bright and strong at all times... :/

takes a lot more power to start a bike then just run it.

[t84]

Arse, I'll get the battery on the Optimate tonight and see what it's like in the morning

[Hooli]

got a voltmeter?
if so check the voltage across the battery terminals with the bike reving at about 4-5k - should be 14-14.5v
check it again after 5-10miles as ive had a few charging faults in the past that didnt happen until the reg/rec warmed up.

[DaleJ]

Was it the VFR that had problems with the reg/rec? I remember someone on here who swore by bolting a heat sink to it, dunno if it's related.

[t84]

Reg/Rec/Charging system has been tested!

It could actually of been about 5-6 miles instead of 10, likely to make a difference?

[darkyoung1000]

My boss has a VFR and the charging / reg/rec has been the only part with which he's had problems. It makes practically no charge on tickover in standard format (he's installed a gizmo to check it) and if the battery is in any way weak, the indicators/brake light etc. can be enough to finish it off (I think the output of the alternator only 'just' copes if everything's on.
What were the riding conditions like when it happened to you?

Cheers,
Tom

[moto_traxport]

VFR800 has a load of earths meeting at a big junction block on the left hand side (under rear end of tank area from memory) and this can catch water and short out. Unwrap it and sort it out if its all green and corroded.

These earth problems can often give quite strange electrical issues and people often do the reg / rec first as the VFR's reputation precedes itself....

[Dr.Doofenshmirtz]

Honda regulators are renowned for this.
The fix is to bolt a computer's 12v PSU fan on top of the regulator to keep it cool whilst riding...it also helps if you bolt the other side of the regulator to a large aluminium heat sink.
But by the sounds of it yours is already toast and will need replacing, so it's worth doing the mod to save the new one.

[t84]

It's not the reg/rec, it's already been tested, mine is also an fi-y model which roes out of the factory with an updated part

[Andy OH]

A mate at work has had identical problems with a 2007 VFR. He's had the reg/rec changed, new battery and now the alternator changed. It did take a while for the dealer to get everything sorted for him, but all seems to be ok now.

[BarnatosGhost]

t84,
EXACTLY the same thing happened to mine (Fi-X, so older reg/rec), and it was solved by replacing the battery and reg/rec.

I'm sure your mechanic knows what he's doing, but a double-check / second opinion wouldn't hurt!

[Hooli]

i still say check the reg/rec right after a few miles of riding. they can fail when hot so even if its been checked in the garage the fault wouldnt have shown.

[t84]

Garage checked reg/rec when hot

Right, battery is fully charged on Optimate, rode 5 miles to work, am going to take it out tonight and see if it's still knackered, how many miles would it take to completely drain the battery?

[ajk]

t84 said:

Reg/Rec/Charging system has been tested!

It could actually of been about 5-6 miles instead of 10, likely to make a difference?

Make sure you've checked that it's charging with the headlights on, I had a similar problem a while ago and turned out to be a bad connection that meant was not charging with lights on (AA chap tested it with lights off and said it was battery so I ended up buying a new battery I didn't need).

[t84]

Just rode it 30 miles, got it home, very very weak turning the bike over, back to the garage it goes

[BarnatosGhost]

can you tell us what voltage it's putting across the terminals at c.4,000 revs, lights on and off?