post #1 of Old 10-18-2005, 02:06 AM Thread Starter
gus R6
Join Date: Apr 2005
Location: Melbourne
Posts: 7
Exclamation Regulator/Rectifier burn out. What causes it?

Hey guys,

Well it seems I have the same story as everyone else here.
I replaced my battery a couple of months ago and it's dead already and the more I rode the flatter it got. I was down at Phillip Island for the MotoGp last weekend and my bike wouldn't start after the race, tho it had enough juice for the lights and an attempt at a start. So I roll start it and sit on an average of 130kmph on the way home. After about 40 minutes I start getting weird speed readings, the fuel light's on with a full tank of petrol and the engine light is flashing at me.

I finally get home (still ran ok), turn it off and turn the key back to on and there's nothing at all and the battery is almost hot enough to burn your fingers.

So my new battery is screwed and my regulator/rectifier is burnt out on the red and white connections.

Does anything cause this?
Or is the R/R just the weakest link in the chain?
Why doesn't it's fuse blow first?

The new battery (Yuasa) and R/R is going to cost me AU$480 so I just want to be sure it's not going to happen again if I can avoid it.

This seems to be happening to a lot of people ... is it worth a sticky?

Gus R6

P.S. With my battery out of the bike and after a jump start, my bike at idle reads between 14.5Volts and 15.5V at the battery terminals (mostly sits around 15V). When I rev it, it goes down to 7V and stays that way for about 1 minute before it jumps back up to 15V.
Is this a normal Voltage output from the Stator?
Most things I've read say it should have 14+V at 5k rpm.
Is 15V too high?
Or is it only reading that high because there's no battery in the ciruit?

P.P.S Gotta wait a week to get a new R/R
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post #2 of Old 10-18-2005, 03:09 AM
I go 60km/h nia
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Join Date: May 2004
Location: Fine City SGP
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Usually the RR contacts fry because of high contact resistance from the loose connectors. You'll save that from happening either by tweaking the stock connectors to grip tighter on the RR's spades or swapping out the stock ones as detailed in the how-to section. The RR isn't the weakest chain, at least for the 03+. I think the RR is different from previous yrs and mine is working fine after 2yrs and .

"With my battery out of the bike and after a jump start" ? Is your bike idling without a batt? The battery serves as a voltage buffer, you'll get weird readings this way. Usually the RR survives the contact frying, but your RR looks like it may be screwed from the kind of voltage it is putting out, check it again with the batt reinstalled. 15.5V is way too high and will toast a batt but it's fine for a short while.
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