1977 z650b1 project with pics [completed!!!]

So thank you everyone who has so far given me help with this. I finally got my camera figured out, so here are some pics of the progress. I just realized the other day, I think this is a particularly early production bike, maybe... i have at least 3 zeros in the frame number.

Here is a shot of her a week before i picked her up. Black is of course not a stock color, nor was it i that painted it, but i think it looks pretty sweet. When i first checked her out, engine would start and has 21,000km, which in miles is only about 13,000 miles.


So the night i payed her off, though she would be able to sputter her way over to the garage, only about a mile away, but she wouldn't start. So we trucked it over and started from there. The first thing i started on was the carb. And damn it was dirty, i spent two day cleaning it, had to order new float bowl gaskets, and new rubber tubes from the airbox.



Then i stripped and coated the inside of the tank, was also pretty bad.


After that i installed a new ignition switch to replace the old busted one. Bike might have been stolen at one point.

if you look you can see the cool japanese red "speed-over" indicator mounted on the handlebars. Stock part for japanese kz's.

Thought some people might like to see my friend's early 60's honda cb250. I'm not sure about in the States, but here in japan it is a very rare bike.

this weekend after numerous checks and doublechecks, i decided to try to fire her up again. She kicked to life after only three kicks, but something was wacky. She would only run on choke, and although all cylinders were firing, black smoke was coming out from the left exhaust only, which meant the smoke was coming from cylinders 2 and 3 (center two). I felt the pipes where they come out of the engine, 1 and 4 were warm, 2 and 3 were piping hot. Probably something is still wrong with the carb. I think I will pay the mechanic to help me balance them properly. Sometimes there is no substitution for an experienced hand . Someday i will improve! Anyways, i'm kind of his apprentice, so we'll do it together, its a good way to learn.


Since i started this project, one of the first things i realized was how messed up the wiring is. At this point, i cant even describe whats going on in the left side panel. I have cut wires, mystery colored wires, connectors with missing wires....... such a mess. This is my first time doing wiring, so i'm really struggling. I bought a new PMC regulator/rectifier, but I have no idea how to wire it. I have been looking at wiring diagrams, but its not very helpful. Since the new reg/rec is aftermarket, i'm not sure if the wire colors match exactly. Also, im confused since this new part is a regulator and a rectifier, does that mean that i dont need my old regulator (the box with 3 wires coming out)??? I just need to know which wire to connect to which wire. Any help is appreciated

lets start with your carb problems first it sure sounds to me like there is still something in your pilot circuits that is plugged up. also double check that all the settings are back to stock or at least use a baseline setting for instance 1 1/2 turns out from lightly seated on your mixture screws. if that is good then i'm afraid you will be diving back into those carbs to clean and blow everything out with compressed air. carb syncing is not going to be your problem. if you have a yamaha or suzuki shop close by both of them make great products for carb cleaning at least over here they do. and say hi to your mechanic buddy from a twenty year vet of the motorcycle repair business myself.

what color are the wires coming from the new regulator/rectifier assembly. and also how many.

as far as my carbs go, by "pilots circuits", do you mean carb settings? Before i reinstalled the carb, i double checked that all of my mixture screws were 1.5 turns out. I am certain they are all set the same, so it shouldn't be a mixture problem, right? I cleaned out the carbs very very well, so i am certain they are not still dirty. my mechanic friend said it might have to do with float settings or those little springy pins that sit under the float tabs. I also replaced all the spark plugs and tested for spark, all are fine.

As far as regulator/rectifier, it has 3 yellow wires, 1 white, 1 black, and 1 red wire. All of the wires are hard-wired into it, and since the 4-plug connector that came with it will not fit my bike, i plan to cut it off and just connect all of the wires individually with bullet connectors.

Here's a picture of my new regulator/rectifier. Sorry for the poor quality.



I was mistaken, it actually has 3 yellow wires, 1 brown wire, 1 white wire, and 1 black wire. I know the 3 yellow wires are all power inputs from the alternator, and the black wire is ground. I'm not sure what the brown and white wire do. What I'm wondering if I still need to keep my stock regulator (three wire black box) in conjunction with the new reg/rect. Just not sure how to connect everything.

the pilot circuits are the actual pilots jets and passages in the body of the carbs not the mixture screws you will have to remove them and clean those out properly. the three yellow wires are connected to the alternator.

if one or two of the choke wells are plugged it would do exactly as you say one or two pipes hot and the others cooler. pull the carbs and make sure the choke wells are cleared out good. where in japan are you?? i have been there many times for work ( fujifilm ) in the last 10 years. odawara, hitachi, matsuyama and toyoshina

perhaps I didn't clean the carbs as well as i thought. Thanks for the advice, both of you.

I live in Shiga prefecture. Its quite countryside, but its nice since we have lake Biwa, largest lake in japan. I'm not familiar with the areas you mentioned, except Matsuyama. I'm surprised you have been there, not many people get the chance to visit that part of japan, its in Shikoku. I'm planning to go touring there as soon as i get my bike running.

I hate to be the one to tell you, but that reg/rec you bought is for a permanent magnet alternator and won't work with the 77 650's excited field alternator, here's a very basic explanation why:

As the name suggests a permanent magnet alternator has a rotor/flywheel that is permanently magnetic - or rather, the rotor has permanent magnets attached to it, as the rotor/flywheel rotates the magnets pass by the stator windings and alternating current is induced in the stator and sent to the rec/reg.

In an excited field alternator the rotor/flywheel is not magnetic but has some oddly shaped 'ribs' - the magnetic field is created by applying power to the field coil that sits inside the rotor/flywheel. As the rotor/flywheel rotates through the magnetic field, the ribs disturb the field and alternating current is induced in the stator windings.

The main difference however is how the regulator works: a permanent magnet type regulator works by shunting excess voltage to ground where an excited field type regulator works by interrupting the power supplied to the field coil.

Your permanent magnet 3-phase type combined rec/reg has 6 wires: 3 yellow stator wires, a black ground, a brown voltage sense wire and a white (or white/red) output to battery (a 1-phase permanent magnet type as most of the 650's only has two yellow wires, the rest are the same). Neither have any output wire to the field coil and no way of controlling the power supply to the field coil. With the engine running the permanent magnet alternator is constantly putting out AC - after the rectifier turns AC to DC, the regulator shunts excess voltage to ground and sends correct voltage to the battery.

Your excited field separate rectifier has 5 wires: 3 yellow stator wires, a black ground wire and a white (or red/white) output to battery. After the rectifier turns AC to DC it sends voltage straight to the battery.

Your excited field separate regulator has 3 wires: a brown voltage sense wire, a black ground wire and a green wire that is the output to the field coil.

The excited field type regulator is basically an adjustable electromechanical relay with a coil and a points set - when there's excess voltage on the brown wire the regulator/relay clicks and interrupts the power output to the field coil (green wire), there's no longer a magnetic field in the alternator and no AC output from the stator until voltage on the brown wire falls, the regulator/relay clicks back and restores power to the field coil.

So yes, you will need your old regulator - you will also need a rectifier that fits your excited field setup, sorry.

Let me know if you need pics and part numbers.

OnkelB wrote:

I hate to be the one to tell you, but that reg/rec you bought is for a permanent magnet alternator and won't work with the 77 650's excited field alternator, here's a very basic explanation why:

As the name suggests a permanent magnet alternator has a rotor/flywheel that is permanently magnetic - or rather, the rotor has permanent magnets attached to it, as the rotor/flywheel rotates the magnets pass by the stator windings and alternating current is induced in the stator and sent to the rec/reg.

In an excited field alternator the rotor/flywheel is not magnetic but has some oddly shaped 'ribs' - the magnetic field is created by applying power to the field coil that sits inside the rotor/flywheel. As the rotor/flywheel rotates through the magnetic field, the ribs disturb the field and alternating current is induced in the stator windings.

The main difference however is how the regulator works: a permanent magnet type regulator works by shunting excess voltage to ground where an excited field type regulator works by interrupting the power supplied to the field coil.

Your permanent magnet type combined rec/reg has 6 wires: 3 yellow stator wires, a black ground, a brown voltage sense wire and a white (or white/red) output to battery. It does not have any output wire to the field coil and no way of controlling the power supply to the field coil. With the engine running the permanent magnet alternator is constantly putting out AC - after the rectifier turns AC to DC, the regulator shunts excess voltage to ground and sends correct voltage to the battery.

Your excited field separate rectifier has 5 wires: 3 yellow stator wires, a black ground wire and a white (or red/white) output to battery. After the rectifier turns AC to DC it sends voltage straight to the battery.

Your excited field separate regulator has 3 wires: a brown voltage sense wire, a black ground wire and a green wire that is the output to the field coil.

The excited field type regulator is basically an adjustable electromechanical relay with a coil and a points set - when there's excess voltage on the brown wire the regulator/relay clicks and interrupts the power output to the field coil (green wire), there's no longer a magnetic field in the alternator and no AC output from the stator until voltage on the brown wire falls, the regulator/relay clicks back and restores power to the field coil.



So yes, you will need your old regulator - you will also need a rectifier that fits your excited field setup, sorry.

Let me know if you need pics and part numbers.

Very well put on the differences between the two.

So if I have a rectifier with 5 wires (three yellow, one black and one white) it would be for an excited field rectifier and not a permanant magnet rectifier.

How many wires are on the permant mag rectifier compared to the excited field rectifier?

The reason I ask is I have a rectifier with 5 wires that I thought was for my 900 which is permanant magnet. But from what you describe it would fit my 77 650B1 which is excited field?

These questions are for the separate regulator/rectifier charging systems not the combo systems.

I am not trying to hijack the thread, just trying to understand a little more

Kawickrice wrote:

So if I have a rectifier with 5 wires (three yellow, one black and one white) it would be for an excited field rectifier and not a permanant magnet rectifier.

Not necessarily, it depends on how your regulator is working - some bikes with permanent magnet alternators have separate rectifier and regulator.

I should also have added that some combined reg/recs for permanent magnet setups don't have the brown voltage sense wire.

How many wires are on the permant mag rectifier compared to the excited field rectifier?

That depends on the number of phases - a 1-phase alternator/rectifier has 2 yellow wires, a 3-phase has 3 yellow. Both will also have a black and a white and possibly a brown. The 77 650 excited field setup is 3-phase, 78 650 and up are 1-phase permanent magnet until the CSRs (if I remember correctly) that has a 3-phase permanent magnet setup.

The reason I ask is I have a rectifier with 5 wires that I thought was for my 900 which is permanant magnet. But from what you describe it would fit my 77 650B1 which is excited field?

I'm not all that familiar with the 900s electric system, but I take it you have a 900 with permanent magnet alternator and separate rec and reg, right? The main difference between permanent magnet and excited field (apart from the alternator obviously) is how the regulator works, the 5 wire rectifier (if it is indeed a separate rectifier) you have will probably work with both systems as long as it's 3-phase (3 yellow wires) - do you have a part no. for it? If so I can check against my own 77 650.

I am not trying to hijack the thread, just trying to understand a little more

Not hijacking at all, if the rectifier you have will indeed work with both systems it's valuable info.