Combo Regulator Rectifier - 79 XS400F

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TimBuz

XS400 Enthusiast
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So I've got a 79 xs400F that I'm in the process of tidying up the battery area and moving all electrics to the under side of the seat pan. I'll be keeping electric start and getting a smaller lithium battery similar to this
http://www.ebay.com.au/itm/SSB-12V-..._Parts_Accessories&hash=item4176a3602a&_uhb=1

ATM I've got a separate regulator (3 wires, green black and brown) and rectifier (5 wires, 3 white, a black and a red). But I want to get a combined reg/rec for piece of mind with the new lithium battery and also to keep things tidy and eliminate the need for an extra component.

At the moment all i have found is this http://www.regulatorrectifier.com/catalog/1979-Yamaha-XS400F-Regulator-Rectifier its got the 2 plugs and all wire colours match up but its a bit expensive at $128 shipped at aus. I've found a couple of others but they only have the green and brown wires on the second plug, is the black wire needed? is it an earth?
 
I just got mine delivered that I bought on Amazon.

http://www.amazon.com/REGULATOR-REC...773&sr=8-1&keywords=xs400+regulator+rectifier

The plug is different, but the wire colors are the same as the old separate regulator and rectifier. I am going to use the plugs off of the old parts. It should be easy. It's just: black-black, red-red, yellow-yellow, white-white (like marriages used to be in the old south)....the two old plugs just need to share the black (like a vintage '70s "art film" I saw once).

Added bonus- it looks like it will bolt to the original regulator mounting points on the battery box between the legs of the H-Pipe. I have already cut off and ground down the mounting tab for the old rectifier (as is was cracked 2/3 of the way through already). This thing is going to look factory when it is done....unless you happen to know it used to have a separate reg and rec.
 
I ended up just getting the one from the link I posted earlier, I was tempted to get the one from amazon but atleast I know this will definitely work and has the 2 plugs. Hopefully yours works well houghmade seems like their harder to find for the xs400f than later models so should save some people some trouble.
 
I'll report back when it's back together and running. Hopefully in a day or two (stupid job getting in the way).
 
HoughMade said:
I'll report back when it's back together and running. Hopefully in a day or two (stupid job getting in the way).
Click to expand...

TimBuz said:
I ended up just getting the one from the link I posted earlier, I was tempted to get the one from amazon but atleast I know this will definitely work and has the 2 plugs. Hopefully yours works well houghmade seems like their harder to find for the xs400f than later models so should save some people some trouble.
Click to expand...

I'm curious how your have experiences been with these combos?
 
I have the bike back together...mostly.

I mounted the Reg/Rec under the battery box where the original rectifier was. It fits perfectly. I had to charge my battery and briefly got the bike started last night, but there was what sounded like a knocking sound, so I shut it down immediately.

I narrowed it down and found that the right exhaust header was not tight and what I was hearing was exhaust escaping right at the head on every exhaust stroke. When I went to tighten the header bolt, I discovered I had cross-threaded it (which explains why it felt tight, but wasn't) and I stripped the threads.

Therefore, I have not had the bike running long enough to test the voltage. I can confirm that there are no shorts, however. I already have the stud I need and will be trying it again tonight, this time with a fully charged battery. Hopefully no later than tomorrow, I will be able to report whether of not the Caltric Reg/Rec I used (from Amazon) is working.
 
I only had it running for a few seconds today as something else is going on, but it was running long enough to measure it at 14.5 volts at around 2000 rpm. However, that was with starting with a well charged battery.
 
fR3ZNO said:
Anyone have any results with these Rectifiers and Regs?
Click to expand...

I picked up this reg/rec combo unit a couple weeks ago. I'm in the middle of a move and then leaving the country on the 25th for two weeks. Between all that I haven't had a chance to even try it...:doh:

Soon as I do I'll post results and details :thumbsup:
 
Considering picking up a used rectifier from eBay for my '81. Good idea? It's like $15 shipped and the seller has a good rating.

Not sure how high the failure rate is on these things... is it worth it to just buy an aftermarket one and deal with the wiring?
 
fR3ZNO said:
Considering picking up a used rectifier from eBay for my '81. Good idea? It's like $15 shipped and the seller has a good rating.

Not sure how high the failure rate is on these things... is it worth it to just buy an aftermarket one and deal with the wiring?
Click to expand...

I first went with an aftermarket Reg, and am now switching to a combo reg/rec. In my opinion, I should have just done the combo unit from the get go. More wiring to think about, but it's also a more long term solution. Plus you eliminate two of the main failure points in the charging system.

Imagine how annoying it would be to replace a rec only to then have the reg fail shortly after...:doh:
 
Vroom4 said:
I first went with an aftermarket Reg, and am now switching to a combo reg/rec. In my opinion, I should have just done the combo unit from the get go. More wiring to think about, but it's also a more long term solution. Plus you eliminate two of the main failure points in the charging system.

Imagine how annoying it would be to replace a rec only to then have the reg fail shortly after...:doh:
Click to expand...

Good point. If I go the aftermarket route it will definitely be with a Rectifier/Regulator combo.

I figured the used Rectifier would be a good value if I could get away with it, but if it only lasts a few weeks, what's the point? I guess it makes it a gamble.

I have been considering picking up the combo unit that's prewired for the xs400 that was mentioned in the OP.

Been looking around on eBay and after doing some searching with Yahama part numbers, seems like this will work...

Clicky Click

Found the same thing from other sellers for $89 w/ free shipping!

Yamaha PN is 1L9-81970-60-00

Matches the info given on this page: Clicky Click
 
Last edited:
I purchased a couple of these - Yamaha XJ400, XS400 DOHC, XJ550, FZ600, XJ600 (80-91), XJ650 Regulator Rectifier http://r.ebay.com/zG4VCN - I cut the connections off the old regulator and rectifier and hooked them up to it, the only issue is there are 2 green wires, I found an XJ600 wiring diagram and the 2nd green wire goes to the side stand safety relay, so I believe it's safe to leave unconnected, I haven't tried it out yet but I'll let you all know how it goes
 
Having some issues wiring up the RR that I bought. That one link says the ESR350 should fit the xs400, but the connectors on the new RR are male, where they should be female... Ended up dyking the connector off and splicing in my original one, and then used spade connectors on the wires that go to the regulator. The new RR has only two wires for the regulator portion but the original used three wires. The one missing is the black wire. I believe that is ground. Got everything hooked up and the bike still won't charge. Uuugghhhhh
 

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