FZR to R6 rectifier mod. problems over heating

[fzrmodking03]

BACK GROUND info
I did the R6 rectifier mod last winter because my bike blew two of the stock ones already.
Problem
even with the mod I am still blowing rectifiers.
I just blew a 1996 rec. and put on a 2001 and it is over heating.

WHAT I KNOW

two of the white wires going from the alternator to the rectifier were burnt brown at the rectifier connection ports.
the bike is producing 13.34 volts at the battery when running.
and 12.03 with the bike on.
11.88 when off

[bboystyleus]

I just had the same problem and fixed it, one thing you can do to help cool of the rectifier is use thermal paste, silver based preferably. It will cool from 2-5 degrees extra.

I am also thinking of getting an electronics heat sink and gluing it with thermal adhesive.

[ragedigital]

Sounds like you may have an issue somewhere else causing it to overheat. Your output voltages don't look out of whack. I wonder what the input voltage to the VR is when the bike is running.

[thatkid]

WHAT I KNOW

two of the white wires going from the alternator to the rectifier were burnt brown at the rectifier connection ports.
the bike is producing 13.34 volts at the battery when running.
and 12.03 with the bike on.
11.88 when off

The rectifier ground should not be grounded on the rectifier nor the mounting plate, any heat in the ground wire is transferred back to the rectifier. Connect it to the frame or direct to the battery negative.

The two burnt wires indicate a poor electrical connection. Poor contacts cause overheating which will in turn cause the rectifier to overheat. There's another 3 pin connector you should check, it's located under the fuel tank and connects the alternator to the 3 white wires leading to the rectifier. If that connector is burnt/corroded, those wires carry 40 - 60 AC volts which can be a FIRE Hazard so cut both connectors off and

1. buy a suitable replacement
2. solder the the wires together, then insulate with self amalgamating tape.

The charging voltage should be checked @ 3000 RPM, if your reading of 13.34 volts was @ 3000 RPM then the reading is low, possibly caused by poor connections, which will cause the wires to overheat.

"the bike is producing 13.34 volts at the battery when running." was that @ 3000 RPM?

"and 12.03 with the bike on." Was that with the ignition switched on, or idling?

"11.88 when off" Indicates, either a bad battery or, the battery is not fully charged.

Test your charging system by following this flow chart VR Trouble Shooting

[reelrazor]

These regulator/rectifiers take the three phase AC(35-55VAC PER phase)) from the stator and convert it(rectify) to DC (being the 'rectifier' side of the unit).

And then they DUMP the excess voltage to ground (this is where the 'regulator' side of things comes into play).

All told, at decent RPMs, the reg/rect has about 18-20 Vdc available to it.

This is enough voltage to, as you know, kill 12 volt batteries and 12volt electrics (light bulbs, TCI boxes, coils, relays).

The regulator side will limit the upper range of the voltage to 13.5 IF IT CAN, by bleeding voltage into the bike's frame/ground.

If there is ANY resistance in the ground wire from the VR to ground, this will impede the VR's ability to do it's job (dumping excess voltage).

If the excess CANNOT be efficiently bled off, it will cause impedance in all upstream paths.....this means the AC leads from the stator, and even the stator windings themselves.

CURE:

Connect the ground terminal of the VR to one of the engine case bolts DIRECTLY with at least 14gauge wire. CLEAN ALL associated wiring/terminals and USE dielectric grease (including battery ground lead-connect to same engine case bolt)

[bboystyleus]

Is the VR suppose to be hot when it is in use? Or just warm?

[ranmafan]

The rectifier ground should not be grounded on the rectifier nor the mounting plate, any heat in the ground wire is transferred back to the rectifier. Connect it to the frame or direct to the battery negative.

Not sure I follow your reasoning, but if the post below is anywhere near correct, running all the way back to the battery is definitely a bad idea. If the VR does dump a good amount of current to ground (say, a few amperes), you want the shortest length of wire possible, and a very good connection (P=I^2*R...).

I really don't think you need to worry about heat transfer through wires, though.

[pathst]

I was buying some parts from eastern beaver and ran across this upgrade.
Maybe this can alleviate your issues, the write up for what the upgrade does seems to be very helpful.

Wiring parts
http://www.easternbeaver.com/Main/Elec_ ... ctors.html


Write up
http://www.triumphrat.net/speed-triple- ... grade.html

[thatkid]

The rectifier ground should not be grounded on the rectifier nor the mounting plate, any heat in the ground wire is transferred back to the rectifier. Connect it to the frame or direct to the battery negative.

Not sure I follow your reasoning, but if the post below is anywhere near correct, running all the way back to the battery is definitely a bad idea. If the VR does dump a good amount of current to ground (say, a few amperes), you want the shortest length of wire possible, and a very good connection (P=I^2*R...).

I really don't think you need to worry about heat transfer through wires, though.

Maybe I worded that wrongly.

As temperature increases so does resistance, and visa versa.

Wired to the rectifier/mounting plate the ground wire will increase in temperature, creating a rise in resistance and therefore a rise in temperature.

That extra heat will transfer to the negative male spade connector on the VR. The VR will get hotter internally, defeating the object of the cooling fins. Hot electrical connections degrade/oxidise creating resistance. If/when the ground connection fails, kiss goodbye to your electrics.

Whether wired to the frame, battery negative, or as RR suggests to an engine ground, the increased wire length, and therefore resistance will be marginal.

[fzrmodking03]

WHAT I KNOW

two of the white wires going from the alternator to the rectifier were burnt brown at the rectifier connection ports.
the bike is producing 13.34 volts at the battery when running.
and 12.03 with the bike on.
11.88 when off

The rectifier ground should not be grounded on the rectifier nor the mounting plate, any heat in the ground wire is transferred back to the rectifier. Connect it to the frame or direct to the battery negative.

The two burnt wires indicate a poor electrical connection. Poor contacts cause overheating which will in turn cause the rectifier to overheat. There's another 3 pin connector you should check, it's located under the fuel tank and connects the alternator to the 3 white wires leading to the rectifier. If that connector is burnt/corroded, those wires carry 40 - 60 AC volts which can be a FIRE Hazard so cut both connectors off and

1. buy a suitable replacement
2. solder the the wires together, then insulate with self amalgamating tape.

The charging voltage should be checked @ 3000 RPM, if your reading of 13.34 volts was @ 3000 RPM then the reading is low, possibly caused by poor connections, which will cause the wires to overheat.

"the bike is producing 13.34 volts at the battery when running." was that @ 3000 RPM?

"and 12.03 with the bike on." Was that with the ignition switched on, or idling?

"11.88 when off" Indicates, either a bad battery or, the battery is not fully charged.

Test your charging system by following this flow chart VR Trouble Shooting

wow thank you very much that was a huge help. now got to go put it into action thanks.
I also wanted to say that I am extremely impressed with this fzr forum and i am proud to have joined and thanks every one Ill take all this info and put it to use and see how well it works thanks every one

[91FZR]

Hi all, just joined and I've been having the same problem.
I have a 91 FZR 600 and it looks like a previous owner has changed the engine for possibly a YZF 600 Thundercat engine with a 4TV number on it.
I've worked through the VR flowchart and I'm getting between 14.5v and 17.3v at around 3k which would explain why the battery which was new in March this year was empty yesterday when I checked it before I refilled the cells and charged it up. I'm also getting around 40v between all 3 white wires.
reelrazor mentions connecting the ground from the R/R to the engine casing but looking at mine it's only a 4 pin plug, 3 white, 1 red with the earth coming out of the same loom as the 3 whites and attaching to one of the R/R's mounting bolts. Would I be right in thinking that a R/R with a 5 pin connection will have a ground terminal that can be connected to an engine casing bolt or have I missed something? The reason I'm asking is that before I buy a new one, I'd like to find the best way to rectify this problem ie: buy a 5 pin R/R and convert the wiring (I've seen a Thundercat R/R with cooling fins and a 5 pin plug for the same price as a replacement 4 pin one I'm replacing)
Any help will be appreciated
steve

*just found the excellent electrical mods thread which has basically answered my question

[thatkid]

When you've completed the VR upgrade if your battery still goes flat, you probably have shorting plates in at least one cell 17.3v @ 3k (the voltage will increase @ higher RPM's) will boil the battery dry, the plates can buckle and short out, if so that battery will need replacing.

I would NOT ride the bike while it's charging @ that rate, It could fry your TCI and other electrical components causing much

[91FZR]

When you've completed the VR upgrade if your battery still goes flat, you probably have shorting plates in at least one cell 17.3v @ 3k (the voltage will increase @ higher RPM's) will boil the battery dry, the plates can buckle and short out, if so that battery will need replacing.

I would NOT ride the bike while it's charging @ that rate, It could fry your TCI and other electrical components causing much

Thanks mate, been on the trusty mountain bike to work and the new VR should be here tomorrow. Charged the battery on Sunday and it's still holding charge but I'll keep my eye on it.

[91FZR]

Hi guys, the new R/R arrived today
Checked battery voltage first 'cuz it's been stood since Sunday when I charged it up - 12.2v.
Fitted new R/R and ran the earth down to an engine casing bolt. Fired it all up and the first thing I noticed was no sulphur smell and no bubbling sounds like before.
At idle I'm getting 13.7v. At 3k, 14.5v.
Been out for a good ride and re-checked it and still getting the same results methinks it is all good now.
Thanks very much for the info on this site (will look into a donation on pay day!)
Now for the rest of the extensive to-do list