TOPIC:

Hello Guys,

I had a bit of excitement today with my bike. My girlfriend and I went for a ride today in the city ( a bit of stop and go) and were riding for about a half hour before we stopped at a burger stand. I was placing my order when I noticed smoke coming from the far end of the parking lot where my bike was. I ran over and sure enough it was on fire! The fire was first sized and under the battery box where the regulator/rectifier was located and i was able to squeeze it out with a gloved hand before it spread. It was localized n the wires going into the regulator/rectifier. Attached are some pictures of the carnage. The fire damage is mostly on the white wire coming out of the reg/rect and going to the starter relay (it is totally severed and burnt) the ground and one of the yellow wires.
A bit of background; This was probably the longest ride I've taken since transplanting a kz750H motor into this 650 frame. The bike has a stock 750H electronic ignition. Before the ride i was looking into the harness up by the forks as the wire that goes to the speedo light was loose. I also checked out the wiring in the headlight bucket. I just put in a new Motobatt Battery. When installing I was tired/ over eager to start the motor, pulled a bonehead move and started to hook the + & - up backwards ( I did notice a puff of smoke from were the reg/rect would be) , I righted it as soon I could and checked to make sure power was going back into the battery while the bike was running. This last bit is embarrassing to admit but probably important.
I know I need a new Regulator/Rectifier but I want to ask you guys what you believe is the cause. A grounded wire in the harness? damaged reg/rect failing? or something else. Will I need to replace anything else like the starter relay? Any help is appreciated, Thank you.

WOW Chances are it's just the R/R but check for shorted wires anyway. I do a running check on the disconnected stator too. Doesn't look like the yellow wires fried but you never know.
Steve

Connecting the battery backwards was the most likely cause.
From the 1981 KZ650 service manual: 1. Do not reverse the battery lead connections. This will burn out the zener diode.

From info provided by loudhvx, you can use a voltage regulator from a Ninja 250/500 or Vulcan 500 w a 3-phase charging system.
The connector may be reversed on some. From about 2010-on, they don't have a pigtail & I'm not sure if any of those are suitable.
There may be other Kawasakis with the same reg-rec as those EX/VN models.

JMKZHI wrote: Connecting the battery backwards was the most likely cause.
From the 1981 KZ650 service manual: 1. Do not reverse the battery lead connections. This will burn out the zener diode.

From info provided by loudhvx, you can use a voltage regulator from a Ninja 250/500 or Vulcan 500.
The connector may be reversed on some. From about 2010-on, they don't have a pigtail & I'm not sure if any of those are suitable.
There may be other Kawasakis with the same reg-rec as those EX/VN models.

Excellent advice!

AND the most likely cause of the short.

When you reverse bias any diode, (especially with high current) it starts doing it's job of blocking electron flow in the reverse direction. It can get even more complicated in one of todays modern cars, with PCM's and stereo's, along with the alternator all getting smoked at the same time. (the magic smoke leaves the device, much like yours) A VERY expensive mistake.
If your stator winding's were good in the first place, they should still be OK. The yellow are stator wires, the brown is the B+ switched ignition voltage sense wire, the white / red go to B+ usually at the solonoid, and the black wire is ground. It is like a car alternator rectifiers set, only packaged slightly different. I tried to copy and paste the rectifier schematic from my *.pdf manual, but it is one looooong pic file so, I couldn't get it without adding the whole document.

Some are retrofitting some more accurate regulators from a polaris atv, so that they can run the new li-ion batteries, but mine is still a stocker with a gel-cell.

Chinese cheapo stator.. not smoked yet (pic was last week).

Rectifiers do go bad on their own, but some owners help speed up the process.

If you are using the original 1-phase stator (2-wire) from the Kz650, then you need a 1-phase reg/rec, though you can often get away with a modern 3-phase reg/rec and just leave the third stator wire disconnected on the reg/rec.

If you are using the 3-phase Kz750 stator, (3-wire) then you can use a modern Ninja 250/500 reg/rec (like JMKZHI mentioned), used, for dirt cheap or use the various new 3-phase reg/recs available from many manufacturers.

Whatever you do, don't get a used one from the 1980's. Those would be at the end of their lives, if they work properly at all.

Thanks Guys,

I have a newer 3 phase electrosport stator installed so I'll look into grabbing one of the Ninja R/R. Hopefully nothing got damaged with the stator but if so I have the stock one the 750H motor came with. The R/R I burned up was new as well (also Electrosport i believe) so I'm sure I fried it when I reversed the leads. I'm just glad the damage was minimal.

Before buying, be sure to compare the connector to see if it will mate with your wire harness. If nothing matches, you may have to redo the connector. In which case you'll want to use a good crimper for open barrel terminals. good crimps are needed on the reg-rec.

A new voltage regulator for a KZ750-4 should be plug and play.

Electrosport stators make a lot of power and that stresses the bikes wiring. In addition, power created by the generator that is not consumed by the bike itself is shunted by the R/R back to the stator which then creates heat and can shorten it's life. A good mitigation against this sort of damage is by installing a SERIES type Shindengen SH775 R/R. OEM's are moving to series R/R's because they shut off the current flow and help protect the stator and harnessing. You can find SH775's on ebay for $50 shipped or less off ebay, and Triumph sells a nice harness P/N T2500676 that can be used to hook it up. These units are vastly superior to shunt R/R's so it's worth the trouble of installing them. Just be careful when searching for a SH775 because there are tons of counterfeit clones being sold on ebay. Be sure to only buy the unit if you can verify "SH775" is printed on the top.

My Ninja reg/rec suggestion was assuming you had a factory 750 or 650 stator in the motor.

Like Ed (Nessism) said, if you are using a more powerful stator than stock, it may require a different reg/rec than stock (and/or Ninja reg/rec). This is especially true if Electrosoprt recommended a reg/rec upgrade to use with their stator.

If you are going to try a used Ninja stator, you would be better off with the factory 750 stator... but is it fully functional is the question.

Thank you, I'll try to hunt one of those down. I watched this video on youtube describing how to spot the fakes I had ordered a ninja shunt R/R a few days ago for about $15 but would like the peace of mind the series style would offer.

No eBay APP ID and/or Cert ID defined in Kunena configuration

Dirtyhands wrote: Thank you, I'll try to hunt one of those down. I watched this video on youtube describing how to spot the fakes I had ordered a ninja shunt R/R a few days ago for about $15 but would like the peace of mind the series style would offer.

Be sure to get the SH775, not a FH0XX part, because the FH are shunt type and the SH are Series type.

You can often find them for cheaper but this sample came up in my ebay search...

This is want happened when I bought a knock off R/R on ebay. Ruined a brand new stator.
Steve