Bad rectifier? Replacement options in the UK?

[WonkoTheSane]

I just replaced my bulging battery, and she coughed straight back into life.

However, checking the voltage across the terminals while idling at around 1000rpm, it was around 15V, jumping to 17V if I increased the revs.

So the R/R is cooked, I think?

Looking at options in the UK, wemoto.com (biggest supplier of bike parts) lists two options for a '91 model:

http://www.wemoto.com/bikes/yamaha/vmx_1200_v-max/91/picture/regulator_rectifier/ - original type
http://www.wemoto.com/bikes/yamaha/vmx_1200_v-max/91/picture/regulator_rectifier_-_by_electrex/ - some kind of finned R/R by Electrex, doesn't look like either the old version or the newer MOSFET one as far as I know.

For a '96-'03 model they list:
http://www.wemoto.com/bikes/yamaha/vmx_1200_v-max/96-03/picture/regulator_rectifier/ - looks like pictures I've seen of the stock later-model MOSFET R/R

and also the Electrex one:
http://www.wemoto.com/bikes/yamaha/vmx_1200_v-max/96-03/picture/regulator_rectifier_-_by_electrex/

Exactrep list these two:

http://www.exactrep.com/acatalog/Standard--Reg--Rect--Fits-all-Models-1985---2008-124.html#SID=28 - old-style R/R

http://www.exactrep.com/acatalog/He...---Fits-all-Models-1985---2008-79.html#SID=28 - same as the 3rd option above.

I'm on a major budget, but the best bang for the buck looks like the Electrex option if it fits without modification, and is MOSFET (but I'm not sure, the only way I know of identifying a MOSFET R/R is that it has fins but don't know if that's actually accurate). Also, what is the 3rd, black wire? Can that be ignored or is it an earth/ground wire?

Anybody in the UK know a better (cheaper) source? eBay didn't throw up anything obvious.

 

[MaxMidnight]

You could try putting a request in the 'Wanted' section of V Max Chat

Also have a look at this which details how to fit a MOSFET R/R

 

[Miles Long]

No doubt the excessive voltage was the cause of the "cooked" battery.
This happened once to me, on a 650 Yamaha, voltage was so high that the battery exploded, ruining much chrome. But I digress.....

Before replacing your RR, make sure it is properly grounded, either thru the frame mounting (old style), or thru the ground wire, on the newer finned versions. Proper grounding provides a path for the RR to bleed off excessive voltage. That black wire on the ones you linked is a dedicated ground wire.
Also, you can check the RR for correct diode operation. Details can be found in the Electrosport fault-finding chart, in the Electrical "stickies"
Cheers!

 

[WonkoTheSane]

Thanks for the tips.

 

[jfeagins]

Sean Morley sells R/R's and is a site sponsor. Perhaps he ships to the UK?

 

[DMAN999]

It looks like this ElectroSport Rectifier/Regulator ($57.73 US + shipping) will ship to Europe for ($10 per pound and it only weighs 10.4 ounces):
http://www.amazon.com/1998-2007-Yamaha-Vmx1200-Regulator-Rectifier/dp/B0087Q01L2
That's the same one Bill Seward installed on his 1985 Vmax, he posted a review for it there too.

 

[jfeagins]

It looks like this ElectroSport Rectifier/Regulato ($57.73 US + shipping) will ship to Europe for ($10 per pound and it only weighs 10.4 ounces):
http://www.amazon.com/1998-2007-Yamaha-Vmx1200-Regulator-Rectifier/dp/B0087Q01L2
That's the same one Bill Seward installed on his 1985 Vmax, he posted a review for it there too.

That one looks like it also has an added +$40.00 per shipment fee to add, unless I'm looking at it all wrong.

 

[DMAN999]

That one looks like it also has an added +$40.00 per shipment fee to add, unless I'm looking at it all wrong.

That's definitely possible, I took it as a $40 Maximum but it very well could be a $40 minimum.
I guess someone would have to email them for clarification.

 

[WonkoTheSane]

Finally got time to replace the R/R. The stock connector for the three white wires was already gone on the bike and the replacement spade connectors were looking a bit ropey so I got my 6 year old son to chop them off and I fitted new ones.

The new R/R is an Elextrex model and too big to locate in the stock location so I put it under the seat. Soldered on some extensions to reach and took the ground wire straight to the negative terminal on the battery.

Fired the bike up and where I was getting 17+ volts, now getting less than 15V at all RPM I tested.

I had to remove a bit of the cross piece under the passenger seat to fit it in, only question is how to secure it. There are a couple of holes I could probably fit a bolt through but wounded how others had done it. Sean was advocating under the passenger seat, but I don't recall any mention of how to secure it...

Sent from my Nexus 7 using Tapatalk 4

 

[MaxMidnight]

If you are putting it under the seat then I assume it is a MOSFET and doesn't get hot?

I have an immobiliser that is fitted under the pillion seat using suitably sized cross point screws. Too long and your pillion is likely to complain.
An alternative would be double sided sticky pads.