TZR electrical trouble (Bat/RR)

[Killachipmunk]

For anyone who owns a TZR 50, and believes their rectifier is broken or damaged, it is a Half-wave rectifier!

[JimR]

Hello there guys, sorry to make this my first post, but I've been around as a reader on here since I bought my TZR 50 8 months ago!

Brilliant bike by the way. Anyway, I've very recently been having trouble with starting it, only the last 2 weeks or so.

I came out one morning to try and start as normal, but the battery seemed almost entirely dead and I had to bump-start the bike.

Again after college, the battery was pretty much dead and I had to bump again, but when I got home it was pretty much full and cranked at full speed.

This made me guess there was a drain on the battery someplace, which there was when tested (0.06A), disconnected a few things one at a time, when I pulled the Rectifier off the bike the current stopped.

I called up Beechdale Bikes Nottingham (brilliant place, by the way) and the mechanic there suggested that a faulty rectifier could be the problem, drawing current back out of the battery when the bike was stationary.

Background over, now we get to the problem:

I took the Rectifier off and did some tests on it myself with a Multimeter to check if one of the diodes was indeed broken.

This is the rectifier itself, 4 pin only (2 AC, 2 DC)

Here's a wiring diagram for comparison, where part #1 is the magnetic flywheel, #2 is the Rectifier itself, 4 is the fuse and #21 is the Battery.

http://s675.photobuc...mahatzr5003.jpg

And here is my rotated version of the wiring diagram also (was too difficult the right way up due to shape of the rectifier housing)

The trouble I found was that all readings were normal for most of the pins, apart from the Negative DC ones. Readings from - to the left-hand AC pin showed properly, with a reading in one direction and none in reverse bias, but between the - pin and the AC above, there was no reading in either direction, suggesting a broken diode.

SO I bought another Rectifier from eBay, when it arrived the contacts were slightly corroded, but the measurements are exactly the same, - pin and the AC above were closed in both directions.

Have I done something wrong, or is it actually possible that both Rectifiers are broken? If so, I will probably buy a brand new aftermarket version.

Thank you so much in advance,

I'll be looking forward to your help, as I'm just out of experience at this stage.

KC

Just think a little bit more clearly .... you have a multimeter so perhaps connect everything up & start the bike ... check the voltage across the battery ... @ idle you should have battery voltage (may be slightly less if you are running the lights) then rev the motor & recheck the voltage across the battery which should rise to about 20% over battery voltage (14.5 volts (ish) if this happens the charging circuit is working fine (rectifier, VR & mag). Remember AC output from the mag needs to be converted to DC to charge the battery, so part of the rectifier will use a diode to convert the AC into DC hence the readouts from the rectifier. lecture over, I guess the problem you have is a faulty earth on the DC circuit which could encompass any switch or external earth to the wiring loom

[Killachipmunk]

Thanks for the help, but shouldn't the rectifier contain 4 diodes, with current from - able to flow to both AC pins?

I will be checking the charging system when it stops raining, as I can't start the bike without bumping, but from my knowledge of rectifiers, I should be getting a reading from - to either AC pin, right?

[Killachipmunk]

Thanks for your help Jim, I wasn't thinking right and was clutching at straws a bit (this bike needs to be sold soon, and I don't want to be forking out cash) and getting a bit mental.

Turns out it's actually a half-wave rectifier, but with what seems to be an extra diode to the basic versions I know of. I'll check the charging circuit tomorrow and make sure, but seeing as my battery registers about 10 Ohms internal resistance, I think that's the main problem I'm having here. Not a discharged battery, but a ridiculous in-circuit voltage drain.

Sorry to waste your time man.

[Airhead]

Thanks for your help Jim, I wasn't thinking right and was clutching at straws a bit (this bike needs to be sold soon, and I don't want to be forking out cash) and getting a bit mental.

Turns out it's actually a half-wave rectifier, but with what seems to be an extra diode to the basic versions I know of. I'll check the charging circuit tomorrow and make sure, but seeing as my battery registers about 10 Ohms internal resistance, I think that's the main problem I'm having here. Not a discharged battery, but a ridiculous in-circuit voltage drain.

Sorry to waste your time man.

I dont get it, first you quite rightly discover a 60 mAmp drain (leakage) in your rectifier, and prove it by disconnection, next thing you are doubting the battery

is measuring the resistance of a battery a valid test?, to me if you disconnect the battery and it hols charge then it's ok.

[Killachipmunk]

I dont get it, first you quite rightly discover a 60 mAmp drain (leakage) in your rectifier, and prove it by disconnection, next thing you are doubting the battery

is measuring the resistance of a battery a valid test?, to me if you disconnect the battery and it hols charge then it's ok.

Man, I don't really know the true problem, but I put the rectifier back on and I can't re-create that 60mA drain, testing the rectifier as a Half-wave shows all the diodes as properly connected, and I've measured the battery off-bike with a bulb and measured a 10 Ohm internal resistance.

It'll keep a 12V EMF reading like this, but once asked for load from the starter, it dives to 6V.

[JimR]

Man, I don't really know the true problem, but I put the rectifier back on and I can't re-create that 60mA drain, testing the rectifier as a Half-wave shows all the diodes as properly connected, and I've measured the battery off-bike with a bulb and measured a 10 Ohm internal resistance.

It'll keep a 12V EMF reading like this, but once asked for load from the starter, it dives to 6V.

To check the charging system do the following in this order :-

1) Charge the battery

2) Check the charge rate should be 14VDC @ 5000 rpm

if you get 14VDC @ 5000 rpm then replace the battery (job done)

if not

3) Unplug the stator wires and check the resistance between yellow/black or yellow/red if you don't have yellow/black (+ve probe) and white (-ve probe) on Ωx1

if you don't get 0.4 ~ 0.6Ω replace the stator (job done)

if not

4) Check for broken wires & bad earths (this means everywhere switches, indicators, clocks etc)

No broken wires/bad earths replace the rectifier

Yamaha, themselves, do not give read outs for the rectifier nor do they give a schematic of the internals of the rectifier so checking resistance readings across random pins is useless.

After checking the wiring diagram for the 2003 TZR50 (I may be wrong here) it appears to be a DC mag as there is no voltage regulator as such.

So I would guess the white wire supplies DC output from the mag to the rectifier (regulator) which in turn supplies a regulated voltage to the battery (via the red wire) & lights etc (via the blue marked L). the yellow/red (yellow/black) gives the mag the DC input it needs and of course the black (earth) which, if dirty or broken, could cause the battery to discharge

The W/L (white/blue) and W/R (white/red) are ignition so can be discounted

so I guess you are still clutching at straws

Regards Jim