Instrument Cluster won't Cycle / No Tach

[Prothec]

I'm back to fussing with my XJ again. At the end of last season I was left with a non-functional charging system.

I finally got around to swapping out my stator. I also swapped out my tach (was functional, but slow and the needle would get stuck).

After swapping out the stator, I no longer have tach function and the warning indicators don't cycle after startup.

For the tach, I'll check AC voltage when running. So far I just know I have continuity between the 3 white wires and between the 3 white wires and the white wire to the tach.

As for the cluster, anyone know how it knows the bike is running? I assume it's from the signal wire to the tach, so if I get the charging system working, it will magically start working? Of course, my charging system wasn't working previously, although I had a functional tach...

Now the lights come on and the warnings stay lit like when you just turn the key on without starting the engine.

[XJkid]

I have the same issue. Glad you stuck your neck out, now I can tag along.

[Prothec]

I have replaced my reg/rect with an automotive regulator and two radio shack rectifiers.
I'm getting little to no magnetic field from the field coil, but I am showing 12v to each of the brushes (green and brown). I think the resistance across the brushes was right around 6 ohms (green and brown wires).

[Prothec]

Before I go any further, I need to mention, I am rather colorblind. If I refer to "green", it might be gray, yellow, or even red. If I say "brown", it could really be red.

Any idea what you get for voltage with the key on at the 2-wire connector under the seat (green and brown going to brushes connector)? For me, each wire is reading battery voltage to ground.

Because the .002 feeler gauge test shows little to no magnetic field with the key on, I at least know the issue is between the rotor and battery.

The perplexing part is I have resistance between the brushes that seems right...



Considering the green wire is connected direct between the reg/rectifier (lol, this wiring diagram is "Rectifire"), if I disconnect the green wire from the rectifier, I should read 0v at the connector going to the field coil. I assume this wire is responsible for "exciting" the field coil.

[crazy steve]

I have replaced my reg/rect with an automotive regulator and two radio shack rectifiers.
I'm getting little to no magnetic field from the field coil, but I am showing 12v to each of the brushes (green and brown). I think the resistance across the brushes was right around 6 ohms (green and brown wires).

That automotive regulator is likely the problem....

How the charging system is supposed to work is the brushes get a varying voltage put across them which controls the output. With the OEM regulator/wiring, the brown wire is connected to a key-operated 12V source (battery voltage), so you should have battery voltage to ground on this wire when the key is on. Here's where it gets complicated...The green wire should read under 2V to ground with the key on and the motor not running. Start the motor, and the voltage to ground should rise, how much depending on the state of charge your battery has. The difference in voltage between the brown and green wires determines your charging system output. If both read battery voltage to ground, your alternator output will be zero. The greater the difference, the higher the output.

Where your problem likely is is the regulator; most (if not all) automotive regulators work differently, usually by grounding one side of the rotor circuit and varying the voltage to the other side to control output. In this case, the higher the voltage, the higher the output, opposite the Yamaha system. So if you have battery voltage on both wires going to the rotor/brushes, you'll get zero output; there's no 'difference of potential'.

Solution? The hard one, you'll have to get the charging system wiring diagram for the vehicle that regulator fits, and see what the differences are, making the needed alterations. Also note that some will wire differently depending on whether the vehicle was equipped with an ammeter or a warning light. Many of these regulators won't work if a warning light was originally fitted and it's absent from the circuit, so be aware of that. The easy solution, buy a XJ regulator from Geezer, that will be plug-and-play....

[crazy steve]

I should also have mentioned that you have checked the all the wiring plugs from the rotor and stator to make sure they're clean and making good contact, right? Dirty and/or semi-melted connectors will cause problems, make sure those are good.

[Prothec]

Thanks Steve, that definitely helps confirm how I expect this should work.

This is the voltage regulator I'm trying to use:

http://napaautoparts.com/Catalog/Cat...8SB_0092705611

I know other people use this with the XJ650s. I'll take another stab at it when I get home this evening. I may have had the leads hooked up backwards to the regulator and could have fried it when I was messing with it in the fall.

Ultimately I'd like to get this setup working as well as buy a reg/rect from Geezer. I like the "do it yourself" approach where I screw things up worse first before I admin defeat

[crazy steve]

This is the voltage regulator I'm trying to use:

http://napaautoparts.com/Catalog/Cat...8SB_0092705611

Your basic Mopar solid-state regulator....

Connect the brown wire that has 12V on it when the key is on to the center pin; this should also go to the rotor. Then connect the green wire from the rotor to the other pin, and nowhere else. Make sure the metal housing is grounded, and that will do it for the regulator.

The whites, reds, and blacks all connect to the rectifier only, with the whites being AC input, red is DC output and black is ground. I should also ask if the rectifiers you're using are full-wave or half-wave as they do connect different. The OEM units are half-wave....

[Prothec]

I have two 25A/50V full-wave bridge rectifiers:

http://www.radioshack.com/product/in...ductId=2062584

That's how I have it set up :S I probably need to get my wife in the garage again to verify wire colors, but regardless, I'm getting 12.2v at the two red wires going to the regulators AND the green and brown wires going to the rotor... Since I have the headlight off anyway, I started disconnecting the connectors to the cluster and no change at the other wires.

Just to clarify, I am checking voltage at the green and brown wires separately to ground from the harness with the connector disconnected.

I re-verified continuity between the connectors and the spliced wires to make sure they were the right color wires at the components...

Here are a couple pictures of what I have put together right now.

[crazy steve]

You're short a rectifier; if you're going to use full-wave, you need three of them. You're giving up 1/3 of your output.....

Here's why: you've got three leads coming out of the alternator, the three whites. Let's call them A, B, and C. You get usable AC output between:
A - B
B - C
C - A
With only two units, you're only getting usable power from between the two pairs you're hooked to. So you need a rectifier between each pair.

Every three-phase vehicle alternator uses three rectifiers, but they always use half-wave. Main reason is this uses fewer diodes for the same result because they're connected differently, plus with fewer diodes less heat is generated. Not to mention it's cheaper....

[Prothec]

I think I'm going to pick up another regulator when I leave work.. I'll write down the numbers I'm getting on what wires this evening before I try swapping them out.

[Prothec]

SWEET.. I swapped out the regulators with another brand that I picked because it didn't have the powder coating on the case and my field coil is magnetizing now.

Before I swapped them I checked continuity and resistance between the pins and the case to see how they vary. I'll post the difference in readings once I start it up and test it further.

Thanks for the help Steve.

About the rectifiers, I take it that it is better to swap them out for three half wave rectifiers, then, or should I stick with the full wave and just add a third?
I have an abundance or cpu heatsinks that I've cut the fins down on for clearance (overkill, I'm sure).

[Prothec]

I hate posting a bunch of times in a row myself, but I think it helps other people who might be going through the same frustrations as I catalog what I've been doing.

I now have a working charging system!

Battery voltage now reads just over 13v at 1100 rpm and rises to around 14v at about 3000 rpm.

I started it up after I saw that my field coil was working, but it still wasn't charging. The cluster cycled through the warnings, but the tach didn't work. I apparently left it disconnected when I was disconnecting/reconnecting wires last night. I connected it and got a working tach. Of course, it still wasn't charging.

I checked the resistance through the brushes/rotor at the connector and it read >7 ohms, a bit high, so I pulled the cover, pulled the stator and brushes, and lightly sanded the rings, pulled the brushes, checked the resistance of the brushes themselves, the wires between the brush places and the connector, and the brushes to the connectors. 0 ohms through the wires and around .4 ohms for the brushes. Between the slip rings on the rotor was, I think around 3-4 ohms. I put everything back together and it then reads a solid 4.7 ohms at the connector, 4.8 ohms on the harness side from the back of the connector with it connected.

Still not charging, I was about to give it up for the night when I saw the connector to the harness going to the rectifiers unplugged sitting on the carbs.

Long story short, my charging system is working again

I can finally finish mounting everything and move back to my carbs!

On another note, last Fall I sanded down the surface of the rotor pretty good because at some point many years ago before I had the bike, apparently the stator cover had something go through it and/or was damaged when it was laid down at speed. It had a pretty good divot in one of the rings, so I ended up sanding the whole surface until it was completely flat.

[crazy steve]

About the rectifiers, I take it that it is better to swap them out for three half wave rectifiers, then, or should I stick with the full wave and just add a third?
I have an abundance or cpu heatsinks that I've cut the fins down on for clearance (overkill, I'm sure).

Just add a third full-wave. I looked, and I couldn't find a half-wave rectifier with enough ampacity to work for a reasonable cost. Do add the third rectifier; not having it may give the voltage you need, but not the amperage.

Theoretically, the full-wave rectifiers should increase output, plus make it smoother.