Kawasaki GTR1400 regulator rectifier keeps failing - any ideas?

[richardGTR1400]

Anyone had a problem with a Kawasaki GTR1400 repeatedly blowing the regulator rectifier?

I'm onto my third regulator/rectifier in 18 months.

The first time it failed I had a fluctuating voltage and flickering headlights (intermittent) followed by sudden complete power failure (blew main fuse).

Second one lasted 15 months and then the voltage started to fluctuate again and flickering headlights. Voltage would go up to 15.5 and down to 10v. Got it replaced (and new battery), but voltage continued to fluctuate (up to 16 and down to 10v). Went up to 16v especially if the battery was put on trickle charge overnight but if not on trickle charge would at best get 13.5 v. Last week was in slow traffic (so low revs) and the voltage kept dropping (down to 9v) until the computer screen turned off. Battery completely discharged. Jump started it to get home and was OK, but voltage continued to fluctuate, but not dropping below 12v even at low revs.

Taken the charging system to bits. I've checked the stator - does what the service manual says it should (56v per lead at 4000 rpm), battery is new, starter motor relay is working properly. Regulator / rectifier failed again on multimeter testing.

Anyone got any ideas as to why this is happening?

Could it be a fault in the main relay box - which is the only thing I haven't been able to check because one way screens prevent removal to check - has another starter relay in it?

Thanks in anticipation

Richard

[Boomer]

Hi Richard,

Were the replacement rec/regs brand new ones or used ones?
Are you sure your wiring is OK as a short somewhere can fry a rec/reg pretty quick.
The short can be in  switched circuit like indicators or highbeam.

[richardGTR1400]

Thanks Boomer!

They were brand new aftermarket ones. Going to try an original manufacturer one now. Checked all the relays and diodes - all OK. Not sure how to check the wiring loom for shorts so any advice would be appreciated.

Only thing I have found is that the socket to the reg / reg was quite dirty/greasy so just wonder if a bad connection was causing the problem.

Cheers

Richard

[Boomer]

Could be the bad connection causing a short between pins on the rec/reg, but more likely elsewhere.
You'll need a wiring diagram and a multimeter.
You need to check all the connectors that aren't connected to ground(-ve) to see if they have zero or low resistance to ground. Tracing a short can be a PITA but replacement rec/regs are expensive.

[richardGTR1400]

Thanks George

Pulled everything apart. Been all over the wiring loom like a rash. Found a few possible issues (wiring cowl in front under upper fairing which was loose so water could have got in but wiring/connectors looked OK - refitted) and the fuel level sensor wiring at one end was stuck together - looked like manufactured like that, but could have been shorted so separated those. Also found that the 3 wires from the alternator were incorrectly routed under the fuel tank and were being compressed by it. Not sure if I had moved them when looking before for shorts or if they had always been like that. Anyway rerouted them correctly.

Only time will tell....! However it seems to be working OK at the moment and producing correct voltage at the battery now.

Cheers and thanks once again for your advice and the welcome!

[Boomer]

Good news. Fingers crossed it will stay reliable from now on. 

[1ka]

I had one go on my 2nd GTR. Replaced under warranty. I thought it was due to all the crap that gets thrown its way.

[Davio]

Hi Richard, I hope that your reg rectifier is ok. Mine went with about 33k on the clock, I use it in all weathers and didn't have the hugger fitted so the reg/rec regularly got covered in crud. I bought two cheap replacements both failed after very little mileage. I fitted the correct Kawasaki part and everything has been fine 10k on. I spoke to a man about this and he explained that the reg rectifier heats up and cools down many times in its service life and it's possible they overheat. For example my mates VFR 800 had at least 3 genuine articles in it's long life. One possible remedy is to fit a cooling fan from a computer. When mine failed it boiled the battery and the acid leaked over the clutch housing removing the finish. Not a happy bunny. Hope yours is ok.

[richardGTR1400]

Hello Davio

Thanks - very similar story with mine. Use in all weathers. Failed at around 40k. Replaced with (not so cheap) aftermarket ones *2 (1 lasted a year and the other failed immediately) so have now replaced with a genuine Kawasaki one from a salvaged bike (£50 on ebay). Been OK so far since end May so fingers crossed.

Otherwise it is a lovely bike - goes beautifully, - just this issue has shaken my confidence in its reliability. I don't understand why reg/rec issues seem to feature with bikes in general (reports in other makes too), yet cars must have something similar and yet I'm not aware of them failing in the same way.

Cheers for now

Richard

[Burchy]

Car designers don't normally stick the reg/rec in the way of all the crud that kicks off the wheel!

[Boomer]

Fit a hugger. Protects the rec/reg from the crud blasting. 

[Davio]

Hi Boomer, yes I fitted one, but after it failed, kind of like shutting the stable door after the horse has bolted. Richard, I hope that your ebay purchase keeps going. I too cant understand why these components fail with such regularity. Keep it shiny side up!! John