Blowing headlight fuse when engine revs???

[Captain Shapeless]

I'm having a problem with blowing the headlight fuse. At first, I thought I had a problem with the headlight switch, but it appears this may not be the case.

I put a new fuse in for the headlight circuit, and everything worked fine this morning, Got to the garage not five minutes away to fill up, no headlight, fuse had blown. Got home, put another fuse in, checked the switch, everything works - I can switch headlight on and off, full beam fine, indicators and horn works, light stays on. However, as soon as I rev the engine, the fuse blows.

Anyone got any ideas why this is happening? Is it a rectifier problem?

[benny hedges]

yes.

not so much rectifier but regulator.

i can send you an oem one for a tenner +postage.
plug and play. its the old type but it works and will get you out the sjit

you need to address this asap before you boil the battery and possibly kill the stator and ecu & ignition.

[Captain Shapeless]

Cheers Benny.

Just been doing the tests as per the manual and everything seems ok, so it looks like you're right.

Been looking at previous messages, and there seems to be an opinion that a later finned Honda R/R (e.g. like one for a CBR 125) is the way to go - would you agree?

[tony.mon]

Yes, that's the way to go.
There's a great article on Superhawk about MOSFET RR's and how to tell which ones are going to be trouble free.

But the 125's one work fine.

[Captain Shapeless]

Excellent, cheers for that.

Good job it's pay day tomorrow...

[lloydie]

Yes, that's the way to go.
There's a great article on Superhawk about MOSFET RR's and how to tell which ones are going to be trouble free.

taken from said article

Finding an MOSFET R/R...

The "easy" way of knowing if a R/R is MOSFET based, is to look at the markings...

Almost all R/R's for motorcycles are made by Shindengen, and they supply all the manufacturers... Honda, Kawasaki, Yamaha and Suzuki and others...

A MOSFET R/R has a marking with FH-*** on it... The numbers tell the specific output and such... and an older thyristor based R/R is marked SH-*** same here, numbers tell the output... SH stands for shunt, and FH for "FET based shunt"... Ie MOSFET...

Now, it's pretty common that the sellers on eBay doesn't list an image with the markings, or write out the type... So here is a list of known MOSFET based R/R's... Keep in mind that the list is a work in progress, you might get an unsuitable R/R if you go by the list alone, look at the markings for FH-***...

Code:
Kawasaki
ZX-6R 2007-> Cut-n-splice... Either solder, or get both connectors from eastern beaver...
ZX-10 2004->
ZX14 2006->
Concours 2008-> Both MOSFET and non-MOSFET available, beware! (And the tyristor based one seems to need a larger load than the VTR to work)

Yamaha
FZ1 2007->
YZF-R1 2007->
YZF-R1 2004-2006 - Works, but has large fins, making it hard to fit...
FJ1300 2007->
Wildstar 1300 2007->

Honda
CBR 1000RR 2004-2007 - Both MOSFET and non-MOSFET available, BEWARE! Cut-n-splice
CBR 1000RR 2008-> Odd connectors, no plugs available, use spade connectors...
CBR 600RR 2003-2006 - Both MOSFET and non-MOSFET available, BEWARE! Cut-n-splice
CBR 600RR 2007-> Cut-n-splice

[rollingthunderx2]

Bike electrical wiring bits and bobs connectors plugs etc.

http://stores.ebay.co.uk/towzatronics?_rdc=1

http://stores.ebay.co.uk/intobikesltd01283585870

[agentpineapple]

before carl worked his magic on my bikes wiring, i used to push the horn button and my indicators and headlight would stop working(blown fuses) carl traced it to a bodge on the rear of the loom, where someone had taken off an alarm and there were bare wires shorting out the system

[tony.mon]

They're wrong about the R1 version being hard to fit. Just use one bolt position, a bit of cleaning around the bolt area so it makes a good contact and it will work fine with just one bolt. Having said that I always run an auxiliary cable direct to battery anyway. Can't hurt, and it's only a short length, so only a few grams.

[benny hedges]

agree tony - i have a r/r off a cb1100 blackbird and its a lot bigger than the standard effort - only fixes with the one bolt hole.
never had any problems with it.

better off using a later plug n play honda r/r assuming the connectors inside the block are not burnt and green... but if they are you have to cut them back anyway so might as well use any old r/r off any bike and connect it up with spde connectors!
they all do the same job more or less

[VTRDark]

Same here, mine is from an R1 and held by one bolt. I think that list is talking about the later ones with with huge fine that make it deep. http://www.ebay.co.uk/itm/Yamaha-R1-5VY ... 2325b11d9b

(:-})

[Captain Shapeless]

OK, got new R/R, fitted it, no difference, in fact, in a new twist, the fuse blows as soon as I turn on the ignition.

All the wiring seems ok, battery says 12.8v, which seems ok since it's been parked up for a week, but battery leakage is 0.4 mA - I presume that's telling me battery is fried? Will replacing the battery sort it once and for all?

[VTRDark]

Replacing the battery wont solve as a bad battery wont blow fuses. There must be a short in the wiring somewhere. Either a wiring problem or water has got in one of the switches or connectors shorting out. Also check you have the right amp fuse, double check but I think it's the 20a.

(:-})

[Captain Shapeless]

Yep, it's a 20 amp for the headlight - good job I bought shedload of them

OK, ta for that, looks like like I've got a fun weekend with a multimeter coming up

Cheers!

[tony.mon]

. I think that list is talking about the later ones with with huge fine that make it deep. )

Can you ask for time to pay?