My '76 XS360C Restoration

Sounds like the battery could have a short in it or a bad cell. If a battery gets to 8v it's never going to work like it should again.
Thanks Chris.

I bought the battery new 6 or 7 months ago from the local Yamaha dealer so maybe I still have a warranty. I'll have to check.

I did check the fluid levels in the battery and they are all up to the top. I'll check it again but if I still get that reading I'll take it back to Yamaha.

Could my charging system have caused the problem?
I just checked the battery and charging.

Hung a wrench next to the alternator cover and the magnet pulled it to the case when I turned on the key.

I had the Battery Tender on for about 24 hrs and took it off yesterday. Before I started it the battery tested at 13.8V.

I ran the bike up to 4500rpm and the battery was at 13.78V

Seems like it takes and holds a charge and is getting a charge. Does the On/Off problem sound like a short? Or when something heats up it shuts down?
The battery should read 14.5 volts or so at 5k rpms. Sounds like it's not charging. :( Your bike should have a mechanical regulator that can be adjusted. I would look it up in the manual on how to do it. It may be all you need to do.
After much experimentation, and finding out my multi-meter is out by 0.6 ohms, I finally tracked down the problem to a blown diode in the rectifier.

I may as well upgrade to the solid state rectifier regulator combo. Seeing as the XS650 of the same era shares the exact same regulator part number with my bike, I should be able to use this rectifier regulator combo from


As a bonus, with our flagging dollar, it's cheaper at the Canadian site than at Mike's XS.

Is this the one I should use or is there a better alternative? ie cheaper

Thanks for any input.
F**k, am I a doughhead!

When I first began having charging problems last summer I pulled out my workshop manuals and did the external test for magnetism at the alternator cover and it was OK but I went ahead and tested the resistance at the connectors up by the battery anyway. I didn't understand what I was doing and didn't think I was getting the right readings.

Next I disconnected the rectifier and regulator connectors to test them. The numbers I got were very whacky and I figured I was definitely doing something wrong.

Here's where the doughhead part comes in: I connected the stator and field coil back up but not to the connectors that put them into the system.I plugged them into themselves. I also connected the other connectors (where they were supposed to go) into themselves, too. I am saying that very quietly cuz I feel so dumb.

Essentially what I did was isolated the alternator from everything else. The only clue I had that something was further wrong was that my Neutral light was on all the time and my headlight switch didn't work to turn the light on and off. It was on all the time. Those are two of the things in the other connectors where the alternator was supposed to go.

I discovered all this when I pulled the wires down to remove the alternator cover. What?! You can't connect the field coil to the staor and hope it will charge your battery. Idiot!

This is what it looked like up top:


The upside is that I found that part of the problem.
After spending the better part of last week going over my workshop manuals, testing my charging system components, reading all the posts I could find here at and watching no end of YouTube videos I finally ran into a buddy who knows his way around a multi-meter and electrical diagrams. He came over and we went over all the readings again.

The first thing he noticed was that my multi-meter was off by .6 or .7 ohms. So when the resisitance across my stator wires should be .72 ohms and it read 1.4 ohms I didn't know what to make of it. Now of course, I can just take the variation into consideration but I didn't know that before. OK, so my stator and field coil are both good.

I didn't need to take variation into consideration so I was able to reliably test my rectifier and found that one diode is shot.

Here's the next zinger: I have both a Yamaha workshop manual and one I printed from here at Both have misprints in them for testing the regulator. I know nothing of these things and only knew I was getting readings that weren't making sense. When my buddy took a look he immediately knew that the test descriptions had been switched.

Here are the two books and what they say:

Yamaha- bilingual Canadian version

Although the readings they say you should get are very slightly different the big thing is that the boxes with the readings are under the wrong instructions.

At the top of the description where it says to test across the black wire and the regulator base, the results should really be under the next test, where it instructs to test across the other two wires (either black/red and green or brown and green).

Once that was straightened out I was getting the proper readings of 142 ohms between the black wire and the base and 10.2 ohms across the other wires.

These are the workshop manuals for the 1976 XS360. I wonder if the XS400 manuals are similarly misprinted and how many other guys have been frustrated by whacky readings on their regulator tests. Did I miss the post that points this out to everyone so I'm the last guy to know?

I'm just glad I have a bit better understanding of the charging system now. So much frustration does lead to digging in and learning something valuable. My new rectifier regulator combo is on order.
The new Regulator Rectifier is a different size than the old ones so I had to mod the battery box a bit to make it fit.


I used a loom to protect the wires.


The black and red wire is the ground which I ran to the frame.


I also used loom to protect the wires for the stator and field coil. This time I connected them where they are supposed to be and not to themselves.

Now I can move on to disassembling my tach to replace the screws that rattled loose.
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While I had the stator case off I made some new gaskets. This one was broken.


I did some fine tuning after this photo and it fit fine.


I also made one for the outer cover.
As I'm often told, I have some screws loose. This time it's in the faceplate of the tach, luckily.


I'm surprised it only took about an hour and a half to remove my tach, open it up


Locktite in the screws, close it back up with a punch and a hammer


and re-instal it, nicely cleaned up and everything


I'd had another tach apart last year so I had a feel for what I was doing this time.

Now on to changing my fork oil for something heavier or replacing the springs. Not sure. I'll have to measure the old ones first. I'm getting a lot of sag up front.
If you want to look into new springs, I just bought some for my xs360. They're Progressive Suspension 11-1109 19.75" fork springs. Found which ones I needed from an old thread on here. They arrived today, I'm excited to drop them in later this week.

Or, you can look into the 'minton mods' that the xs650 guys seem to love. It's cheaper than new springs and it seems to work pretty well, from what I've read.
I got mine for $70 even from an authorized seller on Amazon. But I guess I bought their last set because Amazon is listing it for over $80 now. I know they're slightly cheaper than that on eBay.
I was putting my carbs back together after receiving the needle jet o-rings and one of the needle jets was bent. As I tried to straighten it, it broke.

I have stock XS360 carbs, BS34 I believe, and the part number for the "nozzle, main (Z-8)" is 341-14941-88 in my parts book.

Although it says Z-8 in the parts book, my needle jet say X-6 on them. If I order the z-8's will they work the same. They look the same in various photos I've seen.

Anyone know? Thanks in advance.
It should say X-6 on them for the 76-77 xs360 and look like this. Notice the stepped holes on them. A lot of these type jets don't have this.


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Hi Chris

Yes, the broken one says X-6 and is just like your photo. My Yamaha manual calls for X-6 as well.

My Yamaha Parts List calls for the part number 341-14941-88 which says Z-8 in brackets.

Yamaha has discontinued that part and my Yamaha dealer couldn't find anything that said X-6.

Mike's and XS650direct carry the Z-8 part for the BS-38 carbs and it looks the same. It's their part #48-0656 at the xs650direct link. Same part as at Mike's.

I've read several posts where you said the parts for the BS38 and our BS34's are the same. Any opinion on whether that Z-8 needle jet will work?

I did several different searches on eBay and none like ours came up there, either.

Thanks for any help here.
You can take a chance that it fits. It does look like the same. Not sure if the two are metered any different. I know the xs400 lists three different needle jets from 77-82 but they all look the same to me:laugh:
Got my needle jets from today. They are Z8's for the XS650 BS38 carb.


They look pretty well the same in real life. The location of the camera lens makes them look more dissimilar here than they really are.


The one difference I can see is the bevel on the inside edge of the new one. I have no idea if that will make a difference or not.


What do you think, Chris? Should they work in my carbs?

I pretty well have to go ahead and try them, unless I can find some on eBay or pick up some 360 carbs before riding season.