Rectifier Replacement

Courtesy of Mark Donaldson (Belrix) Posted 09-06-11 on the Kawasakimotorcycle.org forum

In my Dead Battery, Again thread, some more experienced VN2000 owners pointed me to the regulator connector as a potential source of my charging issues. The rectifier connector often lets the weather in, corrodes, and causes damage to the rectifier requiring its replacement.

In my case, the connector itself was heavily damaged and after a long hunt, including emails to the manufacturer and a third-party harness builder in Japan, I decided the only source for that connector was Kawasaki. Unfortunately, to get that connector from Kawasaki, you have to get the entire main wiring harness (which at $425, is a pretty expensive connector - though you do get two of them for that price).

I decided, in the end, to go with an aftermarket regulator/rectifier, though, coincidentally, it's made by the same supplier for Kawasaki's stock version (Shindengen).

The Kawasaki Vulcan 2000, years 2005 and up, has two rectifiers that are connected in parallel. I played around with my voltmeter and am convinced that they are not feeding different sections of the electrical system or anything tricky like that. They're just simply parallel voltage sources. 

I was worried that a mismatch in voltage output that was likely with mixed R/R models would cause strange current loops in the electrical system so I opted to replace both R/R's with the same model in order to keep everything as matched as possible (even through only one stock R/R was damaged).

So - here's the initial damage. The weather seal on the one connector had worked itself out, water had obviously gotten in, and the connectors were heavily corroded & burnt.



At first I thought the pins in the rectifier were intact enough to save. However that upper left pin was corroded nearly through and snapped off in my attempt to make a new pigtail hard-wired to this rectifier. It's also hard to see the scale in this picture but each pin here is only about 2mm across. I'm fairly convinced that this is too thin to reliably carry the nearly 30 amps of current that this circuit is rated for. Perhaps that's why the pins corrode so badly if not kept pristine.



Below are the pins from the old connector. Most are blackened but the one is completely missing the entire female receptacle.



As a reference, below is the other connector which shows no damage:



After some homework, I decided on the Shindengen FH012 regulator/rectifier. It's a MOSFET-based rectifier so it should run pretty cool. It also seems to be pretty easy to find and the connectors are used on a number of motorcycle so they should be easier to find than the stock connector.

I ordered a pair of kits from Roadster Cycle. Jack Fleming, who runs this little company, was very helpful and responsive. =>LINK<=. Each kit was $125 including shipping and, depending on your confidence with soldering, he's got a couple more kits with more of the pre-wire done for just a couple more bucks.

Note, though, that his kit usually only includes 3 feet of 10G wire for the new battery connections - this isn't enough for the V2K. I asked for 6 1/2 feet of wire per kit and I should've asked for more. If I were to do this again, I'd ask for 7.5 feet per kit so I could run the wire more easily. You have to ask special for this extra wire.

Below is the kit that arrived (USPS priority, took two days from California to Denver):



..and here's a side-by-side of the old & new R/R's. (As a plus, the spacing on the new R/R matches the old one so no drilling of the mounting plate is necessary - just use the existing holes.)



Note how heavy the pins are on the new one below over the old. I think this is a good thing.



This is my first attempt on wiring the stator connector using 12G wire. This turned out to be a bit stiff to manage and I made them too short so I ended up redoing with with longer 16G. In retrospect, it looks like the factory used 14G so I recommend starting with that. Note that I ran the shrink wrap up over the weather seal's sleeve to keep it from backing out and to try to keep water from seeping into the connector.

Make the wires about 14" long or so. It's longer than you'll need in the end but much better to be too long and trim a bit off than be too short and find that copper isn't stretchy at all. You'll need enough length to route from the connectors at the back of the regulator to the stator wires near the front of the radiator.



Below is the connectors soldered onto the wiring harness. In my opinion, crimping the connectors isn't good enough alone. Solder all the joints and cover in shrink wrap.



Now it's time for the positive & negative 12v DC leads. Crimp & solder the connector. Note, the first set of crimp flags is for the copper wire, the second is for the insulation. (after this pic was taken, I folded the flags over the insulation.) Make sure you put the weather seals & shrink wrap on the wire first.



The same wires inserted into their connector, the shrink wrap is shrunk over the sleeve of the weather seals & a tie-wrap added to keep the wire pair from un-zipping over time. (You can see a bit better here and above how I put the weather seals on with their sleeves facing outward. I like this from a water-resistant point of view but you should know that the video shown by Jack Fleming shows them facing in toward the contacts.)



Here's where another picture would help but I didn't do one. I wanted to keep the wiring away from the heat of the exhaust system so my first intention was to run it across the bottom of the radiator to the left side of the bike, then up the frame and under the tank to the battery location. However, unless you pull the tank, there's no space above the ignition coil cover that'll allow the wire to pass. I instead crossed behind the radiator and ran under the right side of the tank. (I'm not real happy with this path and may yet re-run this).

After that, I fed the pair of wires down to the battery. I added the supplied auto-reset circuit breakers to each positive line (it's not in Jack's online directions but the gold contact on the circuit breaker is on the R/R side of the line, the silver connector goes toward the battery). The location for the circuit breakers in this picture isn't very good. Having them on top of the battery keeps the battery cover from sitting tightly on top as designed. I need to move this. If you have the 7.5 feet of wire I recommend in the instructions above, this should not be a problem to locate to a better place.



I ran both the positive & negative leads each into a 6G battery lug so I didn't add too many ring terminals to the battery lug. In retrospect this probably wasn't a problem that needed to be solved. It's difficult to get enough heat into a 6G ring lug to melt the solder effectively and I had to resort to a propane torch to get my solder to flow cleanly and avoid the cold joint. Too much work for too little gain - use the ring terminals supplied in the kit would be my recommendation.

Below is the completed underside. I bought some wire loom for Harbor Freight to protect the wiring. If you do that, make sure you get the half-inch size - the 3/8" is too small.



After that, test with a voltmeter. I had 14.4 volts (+/-) at idle speed with is 2v better than my damaged R/R. I just took it to South Dakota and back and all is still good. I think this is a good option if you, like me, found you've got damaged connectors on your regulator/rectifier.

I hope this helps.  -- Mark Donaldson