DR-Z 400 charging problem

Greg Masters

Greg Masters

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During last weekend's Peak District ride, my DR-Z's cranking speed got slower and slower during the day until it wouldn't start on the button halfway up Chapelgate.

At home on Sunday I charged the battery and ran the following tests:

  • Engine off, headlamp & tail-lamp on for 2 minutes, battery voltage 12.1v
  • No significant current leakage from battery with all systems off
  • Engine running, battery voltage 12.5v (should be 13.5-15.0v) indicating no charging
  • All three generator coils showing around 1 ohm resistance (as per OE spec)
  • Engine running, voltage across any two generator coils is over 80v AC (as specification)
  • Continuity between regulator output wires and battery confirmed OK

So that would tend to suggest that the regulator/rectifier has gone west. Acquired a 'good' replacement off Fleabay, but it makes no difference.

Q: Have I got two dud regulator/rectifiers or is the problem elsewhere?

:confused:

Greg
 
Are you sure your battery is ok Greg?

but from what you describe it still points to the regulator/rec.
 
My DRZ engine running voltage is 12.5-12.7v.

As your voltage went up when the engine is on that means the rectifier is putting something out. So I'll go with your battery being shot.
 
It's knackered, bung me a fiver and I'll take it away for recycling :D

Seriously though, I've been thinking about your info and it all seems reasonable, but the thing that stands out most is the charging voltage looks low to me - I'd expect about 13.5V for a healthy charging circuit.

The thing is, from other posts, you seem to know your way around elastictrickery. Are you measuring the charging voltage across the battery, or from the +ve to the frame? What measuring at the regufier? All I can think is that a dicky chassis connection would give the sort of problems that you're seeing.

Failing that, you may have a borderline regufier - my VFR had a regufier that failed such that it would charge the battery, or run the headlamp, but not both. Guess how I found that out :blast Unfortunately, if the eBay seller wasn't one for running lights, he might have been selling it as A1 quality, but mistakenly :mad:
 
Watch out for those Japanese connectors, after a while they build up a patina on the spades & sockets that do all kind of strange things. Look for heated connections, normally apparent in the wiring thereabouts....:rob
 
Tobermory Womble said:
It's knackered, bung me a fiver and I'll take it away for recycling :D

Seriously though, I've been thinking about your info and it all seems reasonable, but the thing that stands out most is the charging voltage looks low to me - I'd expect about 13.5V for a healthy charging circuit.

The thing is, from other posts, you seem to know your way around elastictrickery. Are you measuring the charging voltage across the battery, or from the +ve to the frame? What measuring at the regufier? All I can think is that a dicky chassis connection would give the sort of problems that you're seeing.

Failing that, you may have a borderline regufier - my VFR had a regufier that failed such that it would charge the battery, or run the headlamp, but not both. Guess how I found that out :blast Unfortunately, if the eBay seller wasn't one for running lights, he might have been selling it as A1 quality, but mistakenly :mad:
Click to expand...

The eBay vendor assures me that the unit he sold me was good (but, in isolation, they are almost impossible to test).

I agree that the charging voltage is too low - I measured it across the battery posts but have also checked for any resistance between the earth battery post and the frame - no resistance; therefore good connection.

My next steps are to check the price of a NEW rectifier/regulator (but I think that will be scary!) and to check the r/rs that I've got on another DR-Z.

:hammer

Greg
 
Greg, I had similar on my DR350, it turned out to be a broken wire between battery and rectifier. I tried replacement units batterys etc too. If you put a fly lead between reg/rec and battery, to bypass the one in the block connector, you may start charging.
 
Keith Chapman said:
Greg, I had similar on my DR350, it turned out to be a broken wire between battery and rectifier. I tried replacement units batterys etc too. If you put a fly lead between reg/rec and battery, to bypass the one in the block connector, you may start charging.
Click to expand...

Keith

I did check that the appropriate connector in the block was showing 12v (and, therefore, it was connected to the battery). But I might try running some fly leads and see what that offers.

However, I've made arrangements with Phil Reynolds to try the R/Rs that I've got on his bike to see for sure if they are good or dud.

Thanks for the suggestion!

Greg
 
I had problems on my DRZ with the charging, and it ended up the battery was NFG
:nenau

Shep
 
Shep said:
I had problems on my DRZ with the charging, and it ended up the battery was NFG
:nenau

Shep
Click to expand...

Shep

I haven't ruled out the battery yet, but my dilema is that the battery appears to work OK. It takes a charge, it produces pretty good voltage and it doesn't fade much when delivering the juice. But, even if it were on the way out, I'd still expect to see a charging voltage of at least 13.5v - and I'm not!

Greg
 
Tim might have the answer, the rotor only gives out 180w peak.

If you're running lights that's ~90W gone (55w+22w+5w+5w). Off-road at low RPM might not cover this which would drain the battery. Stalling and turning over the engine would make it worse.

Rear bulb can be replaced with LED (3w) saving 18W, HID's would lower by 20W.

As said before the DRZ does not have a 13v+ charge to to the battery so yours is fine. I tested mine recently when I made LED indicators and had to ensure the peak voltage wouldn't blow them.
 
Greg Masters said:
Shep

I haven't ruled out the battery yet, but my dilema is that the battery appears to work OK. It takes a charge, it produces pretty good voltage and it doesn't fade much when delivering the juice. But, even if it were on the way out, I'd still expect to see a charging voltage of at least 13.5v - and I'm not!

Greg
Click to expand...

Yep I agree, but your symptoms are very similar to mine when the battery died.

Its a small battery and I feel over stretched in some circumstances.

Don't modern regulators measure the battery voltage/resistance then adjust the charge voltage to suit? so a poor connection or a dodgy battery can cause the same symptoms

Shep
 
snoopy said:
Tim might have the answer, the rotor only gives out 180w peak.

If you're running lights that's ~90W gone (55w+22w+5w+5w). Off-road at low RPM might not cover this which would drain the battery. Stalling and turning over the engine would make it worse.

Rear bulb can be replaced with LED (3w) saving 18W, HID's would lower by 20W.

As said before the DRZ does not have a 13v+ charge to to the battery so yours is fine. I tested mine recently when I made LED indicators and had to ensure the peak voltage wouldn't blow them.
Click to expand...

Maybe, but the article really refers to the DRZ E, not S which I believe Greg has.

(the tight old git will eventually buy a new battery:D)
 
Timolgra said:
(the tight old git will eventually buy a new battery:D)
Click to expand...

Many a true word ... etc

:eek:

snoopy said:
As said before the DRZ does not have a 13v+ charge to to the battery so yours is fine. I tested mine recently when I made LED indicators and had to ensure the peak voltage wouldn't blow them.
Click to expand...

I'm afraid that the official workshop manual says something different.

Greg
 

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I disconnected the headlamp bulb and the charging voltage went up to 14.7v.

I'm not sure what this tell me though. Either the charging system is not shoving out enough beans to support the battery and the headlight, or the battery is soaking up all the beans that the generator does produce.

I'll give it some more thought over a bottle of wine tonight!

Greg
 
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