Motorcycle Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
3,160 Posts
Discussion Starter #1
In the Honda section,I posted a detailed wiring test that found a shorted Voltage regulator....that is,key switch on and the black wire attached to the voltage regulator takes out the main fuse to the bike. I was wondering if there is any sort of test like a resistance test with a multimeter that would confirm the regulator done and not repairable.

New ones are available,but expensive. The shop manual is of no help,except there is a way to adjust clearance sort of like setting a set of points from a feeler gauge. Maybe if I adjust them,the shorting condition will vanish.

If someone has experience with these,I am all ears. At least,the discovery of the short circuit is a real milestone in getting the bike repaired. It is hard to fix anything without being able to get the ignition turned on. Reference thread below.

http://www.motorcycleforum.com/showthread.php?p=1447810#post1447810
 

·
Pale Rider
Joined
·
528 Posts
The Rectifier, and the Regulator, are two different circuits/devices, but they are physically combined into one assembly. This makes them impossible to troubleshoot separately. If one device fails, you end up replacing both, which drives up the cost.

The Rectifier consists of several Diodes (4-6, usually), which either fail as a short, or an open. The Regulator, in modern terms, is a solid-state device, usually with three leads/wires only: it can fail as an open, or short, as well. The Diodes are not directly connected to the Battery (they connect to the Alternator, then the Regulator), so most likely, the Regulator has failed.

[R/R Assembly]

Alternator => [Diodes => Regulator] => Battery/Bike circuits.

The Diodes do not generate much heat at all; the Regulator generates a lot of heat, which is why the combo'ed devices come with large heatsinks. They can be made with off-the-shelf components, but you will spend about the same money, and a great deal more time, putting your own together.

My best advice is to check the connections to/from the R/R unit. If the wires are not shorted when they shouldn't be, then the R/R is bad. There are some aftermarket suppliers who make them with heavier-duty components than the OEM, and they are priced similar, or less, than OEM. Best to shop the Internet for the best price. Cheers!
 

·
ZAMM Fanatic
Joined
·
2,730 Posts
SgtSlag are you sure you don't have that backwards in the automotive world it's the diodes produce all the heat and a vintage mechanical relay based regulator produces almost zero

I can tell you all about 'em and diagnose automotive regulators but I have no real experience with motorcycle ones

OP Can you post some pictures of your devices. Does there appear to be a metal can over some relays that you can pry the lid off. They're re really easy to adjust and all usually have to do is file the contacts with an emery nail stick. You probably have two contacts welded to each other be very careful prying them apart so you don't tear the contacts off the lever arms

I used to adjust voltage regulator from 13.8 up to about 14.2 for brighter headlights. All you have to do is adjust the tension on the different relays
 

·
Premium Member
Joined
·
5,640 Posts
Are you certain that regulator is adjustable? The one on my '70 CB450 is not; it is fixed at ~14.8V, and contains a SCR circuit that shorts out the stator. The screw that fixes the SCR to the case appears to be an adjustment, though.

If yours is, in fact, adjustable, you would need an adjustable power supply that you can set from 12V to 15V, connected to the key switch and ground terminals of the regulator. When the voltage approaches the set point, the third terminal should be shorted to the ground terminal. Set the adjustment to between 14.6V and 14.8V.

BTW, you can probably substitute a regulator from a CB or CL 450, without issue.
 

·
Premium Member
Joined
·
5,640 Posts
Ok, found some regulator references, and it seems it is a relay, not SCR, but it should work the same way. This should be what it looks like inside: http://whatisbez.com/YTM/reg/BEZ_8470.JPG
Not sure how it could be shorting the fuse, unless the wires are swapped on the terminals. If you use an ohmmeter, you should read open between two terminals, and the coil resistance on the third to one of the others. That resistance will be low, so make sure your contacts are very clean, and press hard, so make sure you can tell the difference. If you open the case, it should be clear which is the coil terminal - that's the one that should go to the key switch. In that photo, that appears to be the center terminal, with the ground on the right, and the stator output on the left, but I don't have one in my kit, so that's a guess. When you press the relay arm down, the left and right terminals should short. That screw on the right vertical part of the arm is used to set the voltage, by pressing against the spring that holds the contacts open.

Shooting in the dark, here, without a full wiring diagram.
 

·
Premium Member
Joined
·
5,640 Posts
Found a few wiring diagrams - it appears that the 550 has a field coil, rather than fixed magnets, in the alternator, so the regulator switches power to the field, until the voltage is reached, so ignore what I guessed before about how it works. That means the power from the key goes to the relay coil and to one side of the relay, and the other side of the relay goes to the field coil in the alternator. Third terminal is still ground, so swapping the field and key wires would cause a short. Also, if the field in the alternator is shorted, you would get the same result, so first measure the wire from the field coil to ground; it should not be a direct short, but the resistance may be much less than 100 ohms.
The terminals in that photo are labeled I, F, and E, and the E terminal seems to be connected to the case, so must be ground. Without holding it, I'm not sure which the others are.
 

·
Pale Rider
Joined
·
528 Posts
Wade is correct. I'm accustomed to low power circuits: did the math, and those diodes will likely generate 30W+ of heat,individually (x4 to x6, or 120W to 180W), so yes, the diodes will generate a lot of heat themselves -- my bad. :(

slumlord:
I've read that some of the mechanical regulators were adjustable, early CB750's, for example. The CB750's OEM manual had directions on how to adjust them, I believe. Might want to visit the CB750 forum here, and ask Tools1 (Admin there) for help. He might be able to shed some light on it for you. Here is a listing from their forum on wiring diagrams, and service manuals, which might help, too. Look at the listings below the line on rotor drilling, for wiring diagrams, and downloadable OEM manuals -- try the early 70's models, K0-K4. Cheers!
:coffee:
 

·
Registered
Joined
·
3,160 Posts
Discussion Starter #8
Ok, found some regulator references, and it seems it is a relay, not SCR, but it should work the same way. This should be what it looks like inside: http://whatisbez.com/YTM/reg/BEZ_8470.JPG
Not sure how it could be shorting the fuse, unless the wires are swapped on the terminals. If you use an ohmmeter, you should read open between two terminals, and the coil resistance on the third to one of the others. That resistance will be low, so make sure your contacts are very clean, and press hard, so make sure you can tell the difference. If you open the case, it should be clear which is the coil terminal - that's the one that should go to the key switch. In that photo, that appears to be the center terminal, with the ground on the right, and the stator output on the left, but I don't have one in my kit, so that's a guess. When you press the relay arm down, the left and right terminals should short. That screw on the right vertical part of the arm is used to set the voltage, by pressing against the spring that holds the contacts open.

Shooting in the dark, here, without a full wiring diagram.
I dug through the service manual and there are adjustments and service that can be performed on the unit. The picture you have posted on the link is correct. The screw on the right side that contacts the flat spring is to adjust the voltage. The screw at the opposite end adjusts the gap on the center coil[the round one in the center] This is called the core gap adjusting screw. The remaining screw on the long facing side is called the point gap adjusting screw for the point on the end at the top of the picture The gaps have values that are .002 and .008. The manual also says to check the points for pitting and corrosion and use a points file or emery paper to clean if needed. Once I get the cover removed,hopefully something obvious will materialize. I also need to find out if the separate rectifier is a selenium unit or a silicon unit. I have read somewhere that the old selenium units degrade with time and this is a 1977 bike

The service manual does not describe any other tests to perform,so I will follow everyone's suggestions and see where it all leads. BTW,it is pretty hard to plug in the wires incorrectly because there is a color coded stripe that indicates which wire connects to which male connector.

I will get back when I get the unit removed and inspected

Slum
 

·
Registered
Joined
·
1,133 Posts
Wonder if we all assume that the maker of the motorcycle was sympathetic to the skinned knuck and bruised thigh gang?
 

·
Registered
Joined
·
3,160 Posts
Discussion Starter #10
Well,the regulator is toast. Ohm shows no resistance anywhere, so it all shorts to ground.

I am not certain that the OEM rectifier is selenium or not, but it looks like the best move might be to Sparckmoto for a combined unit that is regulator+rectifier. Probably better off replacing both units in one
 

·
Registered
Joined
·
3,160 Posts
Discussion Starter #12
Thanks!

Now I can test the silicon rectifier and possibly save about $20 by replacing just the regulator.
 

·
lost
Joined
·
1,106 Posts
In the Honda section,I posted a detailed wiring test that found a shorted Voltage regulator....that is,key switch on and the black wire attached to the voltage regulator takes out the main fuse to the bike. I was wondering if there is any sort of test like a resistance test with a multimeter that would confirm the regulator done and not repairable.

New ones are available,but expensive. The shop manual is of no help,except there is a way to adjust clearance sort of like setting a set of points from a feeler gauge. Maybe if I adjust them,the shorting condition will vanish.

If someone has experience with these,I am all ears. At least,the discovery of the short circuit is a real milestone in getting the bike repaired. It is hard to fix anything without being able to get the ignition turned on. Reference thread below.

http://www.motorcycleforum.com/showthread.php?p=1447810#post1447810

I have a couple old Yamaha RD400s that I've been working on. Each had either a bad rectifier or a bad regulator (hey, I'm senile and can't recall which one). You cant' get new ones AFAIK for them but I was able to find an outfit that did replacement regulator/rectifiers and I don't think they were all that pricey (hey, I'm senile, and can't recall just how much I paid).


<edit> They're more than I thought they were, but too expensive is subjective.

http://www.oregonmotorcycleparts.com/Reg_rec_units.html

Sooo, if the rectifier is toast you can get one of these, I think it is VRREM7-H for $145. When I swapped out the Yammie ones the fuse box was lost to the design (they were crap anyway and the mounting plate wouldn't accommodate the new stuff AND the fuse box). I took all the mounting tabs off the plate that held the bits under the side cover, drilled holes in the appropriate places and bolted it down. I just got several spade terminal fuse holders and soldered them into the harness. It all tucks up nice and neat under the side cover.

That Honda may be a different story on the fuse box location (I've got a '78 CB750K and I don't think it would have the fuse box issue), but unless you want to keep it dead stock you may come out ahead if the rectifier is duff.

Where are you getting electrical bits? I priced them off one place and they're expensive. I know the Honda shop I frequent doesn't show any mercy at the parts counter either.
 

·
Registered
Joined
·
3,160 Posts
Discussion Starter #14 (Edited)
I have a couple old Yamaha RD400s that I've been working on. Each had either a bad rectifier or a bad regulator (hey, I'm senile and can't recall which one). You cant' get new ones AFAIK for them but I was able to find an outfit that did replacement regulator/rectifiers and I don't think they were all that pricey (hey, I'm senile, and can't recall just how much I paid).


<edit> They're more than I thought they were, but too expensive is subjective.

http://www.oregonmotorcycleparts.com/Reg_rec_units.html

Sooo, if the rectifier is toast you can get one of these, I think it is VRREM7-H for $145. When I swapped out the Yammie ones the fuse box was lost to the design (they were crap anyway and the mounting plate wouldn't accommodate the new stuff AND the fuse box). I took all the mounting tabs off the plate that held the bits under the side cover, drilled holes in the appropriate places and bolted it down. I just got several spade terminal fuse holders and soldered them into the harness. It all tucks up nice and neat under the side cover.

That Honda may be a different story on the fuse box location (I've got a '78 CB750K and I don't think it would have the fuse box issue), but unless you want to keep it dead stock you may come out ahead if the rectifier is duff.

Where are you getting electrical bits? I priced them off one place and they're expensive. I know the Honda shop I frequent doesn't show any mercy at the parts counter either.
http://www.regulatorrectifier.com/catalog/Honda-201 If you open the link,the regulator that I need is on the top row in the center. I posted this website in the reviews section. I still need to test the rectifier before i decide whether or not to order this one or get a combined unit for $99. Thanks for your help.This may be one situation where I need to research and find out about quality vs. price.
I can also recommend Partsnmore for decent prices on motorcycle parts. Their business model is to offer a very limited selection of OEM-like aftermarket parts for each bike,but at good prices. I plan to purchase all new handlebar switches for the CB550 and they look very much like the originals for $70 each
 

·
Registered
Joined
·
3,160 Posts
Discussion Starter #16
Well,I finally decided to order all three items--the reproduction switches and also a regulator-rectifier combo unit all from partsnmore.com. I figured that possibly the combo unit was worth the extra cost at $99 since it was all brand new. Now that 100.00 steal of a bike is up to $340.00 plus new carbie boots for $4o.oo more. A lot of their stuff is sourced from japan instead of China, and I hope that is true for the rectifier.

Even a tightwad like me can see the value in that.
 
1 - 16 of 16 Posts
Top