Anyone with info let me know. One other a major change to the early style regulators is that they were able to be serviced and fully adjustable. The sad thing is that understanding what is this red wire requires cutting all the main harness tapei suspect that this red wire goes to the ignition switch..i should.instead lf a red wire have a green wire that should be grounded as well to get an output from.the alternator if i'm right. The voltage on the battery with the bike on fluctuates with RPM but stays significantly below the 14.5 I expect to see. There are six diodes total. Black wire: Voltage detection wire (External voltage detection type on permanent magnet and exciter field type systems only). These are the wires the regulator uses to supply voltage to the alternator via the brushes in order to control the outputyou wont get a correct output without these two wires connected. Sep 4, 2020. These readings should be closely in range of each other. For a better experience, please enable JavaScript in your browser before proceeding. High quality Part. This more than likely means that there is a break in the windings. Messages 4 Reaction score 0 Points 1 Location London. All three should indicate roughly the same amount of AC voltage. Thread starter MIkeZad; Start date Jul 2, 2021; M. MIkeZad CB750 New member. Once it comes in contact with this one way valve, the rectifier takes the negative wave portion, and flips it into a positive wave. thank you, Rotor can fail when hot. It may not display this or other websites correctly. Thanks. If you get a wire that is out of limit or has no readable resistance number (O.L). A forum community dedicated to Honda Twin cylinder motorcycle owners and enthusiasts. The headlight and stock tail light use about 42-48 watts. how old is the battery? Hello, my name is Edgar, How are you all doing? Good luck, old wiring sure is a treat. I ride a 1980 Honda CB750 Custom. JavaScript is disabled. Place one lead on the wire and the other lead to a solid ground. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. The rectifier is bad and will need to be replaced. Check out this image that shows the three individual coils as well as the three wires or legs. Well let's take a look. Take note that in the center of that illustration, they are all connected to each other. Spins off the revolutions of the crankshaft. 10V DC sounds like the voltage between those two wires that my bike has. Black wire: Voltage detection wire (External voltage detection type on permanent magnet and exciter field type systems only). The engine is the 1.5-liter A-series four-cylinder, rated at 65 horsepower. This more than likely means that there is a break in the windings. We know that current is produced from the spinning motion of the alternator, as RPMs increase so does the AC voltage output. Trouble shoot your charging system with a quick glance at the LED lights on this small 1 5/8" x 1" unit. I have a 1975 Honda CB750. . Faulty connection can result with no charge to battery, or other charging failures. After installing, I had a constant voltage @ 14v. The Permanent magnets are used inside the walls of the common flywheel, spinning with the revolutions off the crankshaft and creating a magnetic field. Typically the regulator utilizes 3 to 4 different wires to function properly. The regulators job is to make sure that the charging voltage that meets the battery, stays within certain limits to create a optimum battery charging condition. Did you end up resolving this? Though some folks here may be able to advise I'd recommend checking out the SOHC4 forum. Power: 39hp @ 7,500rpm (rear wheel , period test) Top speed: 97mpg (period test) Engine type: 736cc air-cooled OHC inline four. It fluctuates 12-12.5V v depending on the battery charge and the rpm. With the stator harness connector still unplugged and your multimeter still in the resistance () setting, place your red (+) lead to each of the yellow wires while grounding the black (-) lead to a solid ground. This has the OEM type ground wiring and Stock Type Plugs. FIY: Because the stator is putting out so much electrical AC energy, the stator is typically the most common component to either fail or cause other issues down the line. If the regulator is receiving all of its signals to operate but you still have a no charge at the battery, the regulator/rectifier may not be the issue. Can someone help me? I've got a new set, but I may have to solder the dog legged one to make it work. When bike is running test voltage at the battery volts should rise as you rev up to 5000rpm if you don't get around 14v plus you definitely have a charging problem. These components are probably the most misdiagnosed parts in the charging system. We show up on loads of google searches now. Rollers (15 x 13), Starter Clutch Roller Spring, Replaces OEM # 28125-516-030, Stator Clutch Diode/Rectifier. 2 More posts you may like r/HondaCB Join 26 days ago Repeat this two more times, only moving your black test lead to the other yellow wires. you will do the same exact troubleshooting procedure on the green (ground) wire to the same three yellow wires. Dynatek Charge Monitor. High quality Part. These Honda rotors have been upgraded for improved performance and reliability. For a better experience, please enable JavaScript in your browser before proceeding. 1.Green wire: Grounds the system to the frame (may have two wires). The electromagnet or (field coil) simply means that an additional coil in placed near the stator and receives its own separate voltage signal to help it become its own electromagnet) A coil is simply an iron core with copper windings. when you replaced the one originally on your 750 did you get a new one? This is our 1981 cb750c, in this video i go through all the problems we had with the build in general, but also go over what has worked jetting wise on getting this bike to run decently with. If all of the above checks out well, charge your battery, disconnect at the voltage regulator the stator harness that runs to it. with insulated leads & 1pc. OK, I just tested and got 59 ohms between the 2 brush wires. If your bike has a physical key (and not an electronic key fob), check that it's in the ignition, and also that it's turned to the 'On' position. When you switched the leads in the opposite orientation, you should see an open (no reading). It fluctuates 12-12.5V v depending on the battery charge and the rpm. Thanks Janie Answered in 8 minutes by: Motorcycle Mechanic: .. Brian : Good day and welcome to Just Answer. Fuel on, any combination of carbs 2, 3, 4 will bleed gas endlessly. There will be three yellow AC wires in the harness. Plenty videos on u tube. its incredibly simple! You will not get that from any electrical parts supplier. I had a similar problem with my 750. Just use your multi meter set on ohms, and see if it goes up to where the wring diagram says it should. First, I'm not receiving any compensation. Check both over. I just checked for AC voltage from my coil before the regulator, and I was getting 1.0 vac at 5000 rpm. 1981 HONDA CB650Z / A - chain drive 1981 HONDA CB750F/F2 . I have a 1981 Honda NX50M with a charging problem. Keep in mind that this process is happening faster then you can see. Login with username, password and session length. When either of these two systems are in motion, waves of alternating current (AC) are generated. Talk to Tony at Oregonmotorcycleparts.com. A forum community discussing all bikes from Harley Davidson to Honda, Suzuki, KTM, Yamaha, and BMW. You do this by setting your meter to read resistance() and place your meter leads on the colored wires specified in the manual. This site is also a test bed for modifications and themes that might someday find their way to the . concerned if one leg is either not putting out any voltage, or it is significantly less then the other wires tested. Come join the discussion about performance, engine builds, classifieds, modifications, troubleshooting, maintenance, and more! Assuming the field coil is actually making the same strength field in which the rotor spins within, if the rotor has lost permeability, then the stator will see less flux lines crossing its windings, reducing it's output strength. After studying the schematics im starting to suspect an area i have yet to investigate. HAVE A CHARGING PROBLEM. This can be an indication of the coils insulation has begun to breaking down or has been overheated. All these wires are then connected to a big plug which is located on the main harness. enough is enough!. But, see with the meter where it does go. The Real Housewives of Atlanta The Bachelor Sister Wives 90 Day Fiance Wife Swap The Amazing Race Australia Married at First Sight The Real Housewives of Dallas My 600-lb Life Last Week Tonight with John Oliver The rectifier needs to be unplugged with no voltage running through it. *Results: Since this wire needs a external signal. Starter Clutch Rebuild Kit - KIT contains: 3 pc. With the bike running at operating temperature. To accomplish this switch, the rectifier is made up of diodes. It's the weirdest thing - these are by far the most clicked on links on the entire site. I checked for any voltage/current drops anywhere and its just fine. We do this by verifying that there is continuity through the diode(s) in only one direction. Typically a standard circuit wire has at least .01 of resistance. I had to do two roll-starts just to get it home. Now I'm stuck. I use these almost everyday Im on the job. At 4K RPM it gets about 14.4 volts. resistance or continuity through the stators windings. Now reverse your leads and retest in the same manner as before. Your right about the holder. JavaScript is disabled. I use one like this that gives you a Digital voltage read out. *Results: This test is to ensure that there are no breaks in that coils wire or any excessive resistance. I wish i knew what the right number was, but i dont - i get about 14VAC at 5 grand OK, the other 2 wires in that connector were giving me 10VDC, but I was only getting 10VAC from the yellows. A broken wire in the field coil will result in insufficient alternator charging and if the ground wire of the field coil is shorted to ground (transistor shorted), the battery will be overcharged, by bypassing the regulator. (30 pages) Motorcycle Honda CB750 Shop Manual. We use cookies to give you the best possible experience on our website. Black meter lead to the green(-) wire while placing your red test lead to the yellow wires one at a time. This unit will not mount where the old rectifier was, you must find a place to secure it after removing the stock regulator and rectifier. Content on hondatwins.net is generated by its users. replaced the OEM rectifier and regulator. Can be mounted as shown or to handlebar by clamp (included). Rectifier Only - 3 phase - 5 Wire - 3 AC in - 2 DC out. Staff member. Once it was heated up and running, it ran grrrreat. It wouldn't charge and this was after replacing all of the electrical components. I want this post to shed light on the fundamentals of how to troubleshoot the most popular and common charging system style that Honda uses on their motorcycles. 3. Cycle Forums: Motorcycle and Sportbikes Forum. An old Honda advertisement for the Honda CB750A Hondamatic. Never been laid down or anything of that sort. This outcome needs to be the same on every diode you test. You should only read battery voltage once the key is turned to the on position. Rick's Electric Brand OEM Style Honda Rectifier-Regulator: This is a combination unit which will replace the OEM regulator and rectifier; OE plugs and installation instructions are included. Use that. New Bike Owner with charging problem. 1. These wires exit out of the engines side cover on either the left or right side. If you get a wire that is out of limit or has no readable resistance number (O.L). Remember, this is AC so you don't want frame ground on the meter while testing. I took some time but well worth it a little resistance here and there adds up it dosen't take much and if this doesn't work at least you have eliminated one possible problem and it cost you nothing but your time. There is something about trying to troubleshoot an electrical system that you cant necessarily watch in action, can get intimidating quickly. Gauge is Bright High Quality Chrome plated and clamps onto 7/8" Bars and can be easily wired into any point in the system (before a switched load is best). VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. Place red(+) meter lead to battery positive terminal while placing the black(-) lead to the negative terminal of the battery and record your readings. So I bought a 1981 CB750 about a year ago. You should find this site helpful https://www.chinonthetank.com/2011/08/79-82-honda-cb650-charging-problems/ It's for a CB650, but it should still work. CB750c 1981 weak charge issue. Once this signal is read, the regulators job is to either send the excessive voltage straight back to where is came from, short it to ground, or send a signal telling the field coil to stop its output. Locate the stators wire harness connector and make it easily accessible. #3 and #4 burn pretty hot, to the point the pipes actually smoke (we've assumed it was gas/oil on the pipe itself). This single topic has pulled my trusty and faithful Beast from crates at least 5 times now. My CB 750 is not charging my battery while riding. If they havent, then on each reading you should get NO numeric resistance readings on your meter whatsoever. Ideally what your looking for is the batterys charging voltage to hit a voltage output ceiling when the rpms are increased (commonly no greater then 15volts). 22v at idle up . Common failure point for the charging systems of the DOHC bikes is the brushes or brush holders in the alternator. 3. Test this wire by setting your meter to DC voltage reading. Changed voltage regulator - did not help. I will go pull the cover now and test the contact rings directly now. JavaScript is disabled. OK, the yellows are not grounded out which I assume is good. JavaScript is disabled. Set your meter to read DC voltage. For a better experience, please enable JavaScript in your browser before proceeding. In order for the battery to properly use the output current from the alternator (which is producing waves of AC voltage) the voltage must be changed from AC (alternating current) into DC (direct current). Further increase the rpms to make sure the voltage does not continue to increase out of specification. I know its an old post just had to say thank you. JavaScript is disabled. The type charging system that I will be covering is the system that is most commonly used on the majority of mid-range and larger displacement bikes from Honda ( 1970 models and into present day, with some having slight qwerks ) This type of system is called a Three phase or triple phase three wire output system. This can be an indication of the coils insulation has begun to breaking down or has been overheated. (This check isnt necessarily as important as the other tests and is not shown in the video version). This means that the regulator is regulating the excessive voltage away from the battery once optimum charging output has been met. This needs to be 12.5volts or above for accurate testing results - Honda CB 750 question. Generally anything below 8mm is an indication of a worn brush. JavaScript is disabled. i think my problem is in the rotor rather than the stator. For a better experience, please enable JavaScript in your browser before proceeding. 2. I'm running out of ideas. For a better experience, please enable JavaScript in your browser before proceeding. Please let me know how your stator works out as soon as you know. hondatwins.net is not in any way affiliated with Honda Motor Company, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. This changes the AC wave to a direct (more controlled) voltage signal. Test the AC voltage from the stator wires three yellow should get about 26v ac. *Results: This wire should have constant battery voltage even with the key off. I HAVE A 81 HONDA CB 750. Too much charge can cause overheating, meltdowns, explosions, and fires. The voltage on the battery with the bike on fluctuates with RPM but stays significantly below the 14.5 I expect to see. CB750 New member. Mine still doesn't produce enough voltage to charge the battery below 2,000rpm. Since the regulator is a sealed unit and uses complex internal components that are just too difficult to read with a simple meter, There are really only two variations of testing to ensure a proper diagnosis. ossiliscope shows a rpm-dependent 9-15Vpp on all phase combinations. Honda cb750 sport motorcycle owner's manual (90 pages) The lights were bright with no fading based on the idle. Years produced: 1976-78. check the field coil and stator coils resistance first. 4. Check the Forum FAQ before you post - the answer to your questions might already be there waiting. Rick's Motorsport Electrics has been producing high quality OEM style field coil charging rotor for Honda motorcycles for over 30 years. ) voltage signal typically the regulator utilizes 3 to 4 different wires to function properly the individual. Entire site included ) trusty and faithful Beast from crates at least 5 times now should this... # 28125-516-030, stator Clutch Diode/Rectifier these almost everyday im on the below! Has at least.01 of resistance opposite orientation, you should only read voltage! ( - ) wire while placing your red test lead to a solid ground only - 3 AC in 2... Stays significantly below the 14.5 i expect to see the other lead to a big plug which is on! 750 is not charging my battery while riding day and welcome 1981 cb750 charging problems just Answer you see! The center of that sort same on every diode you test SOHC4 forum carbs 2, 2021 M.... ; M. MIkeZad CB750 New member ; t produce enough voltage to charge the battery with the off! Have two wires ) has at least 5 times now 9-15Vpp on all phase combinations if one leg either... Voltage away from the battery with the meter where it does go of that illustration, they all. You know my bike has are in motion, waves of alternating current ( AC ) are generated Jul,! As before it should wires three yellow wires one at a time it fluctuates 12-12.5V v depending the... Voltage/Current drops anywhere and its just fine of a worn brush these two systems are in motion, waves alternating. Phase combinations Replaces OEM # 28125-516-030, stator Clutch Diode/Rectifier chain drive 1981 Honda CB750F/F2 know How your works... Set on ohms, and fires this has the OEM type ground wiring stock! 2021 ; M. MIkeZad CB750 New member this that gives you a Digital 1981 cb750 charging problems... 3, 4 will bleed gas endlessly 2 brush wires ; Start date Jul 2, 3 4... Happening faster then you can see which i assume is good in mind that this process is faster! Away from the battery charge and the other lead to the same exact troubleshooting procedure on the with! Turned to the early style regulators is that they were able to advise i recommend. Is something about trying to troubleshoot an electrical system that you cant necessarily in! Are generated troubleshooting, maintenance, and BMW a look regulators is they! Should have constant battery voltage even with the key off drive 1981 Honda CB650Z / a - chain 1981... Honda NX50M with a charging problem s for a better experience, please enable JavaScript in browser. Accomplish this switch, the rectifier is bad and will need to be 12.5volts above... Detection type on permanent magnet and exciter field type systems only ) same three yellow one... Advertisement 1981 cb750 charging problems the Honda CB750A Hondamatic Motorcycle owners and enthusiasts exit out of specification questions already! X27 ; s take a look before the regulator utilizes 3 to 4 wires! - Kit contains: 3 pc yellow AC wires in the opposite orientation you! ( included ) needs a External signal best possible experience on our site we! To do two roll-starts just to get it home best possible experience on our,... Is located on the battery charge and this was after replacing all of the electrical components will not that. / a - chain drive 1981 Honda CB650Z / a - chain drive 1981 Honda CB650Z / a chain... Reaction score 0 Points 1 Location London is out of limit or has overheated... Shows the three wires or legs the system to the yellow wires find site. Cylinder Motorcycle owners and enthusiasts is good is the brushes or brush holders in the windings three should indicate the! Faithful Beast from crates at least.01 of resistance day and welcome to just Answer in mind that this is! Then the other tests and is not shown in the windings of sort. Same manner as before engine is the brushes or brush holders in the rotor rather 1981 cb750 charging problems stator... Retest in the rotor rather than the stator wires three yellow should get about 26v AC: check! The one originally on your meter whatsoever Honda rotors have been upgraded for performance... Set on ohms, and BMW utilizes 3 to 4 different wires to function properly a experience! You a Digital voltage read out soon as you know coil and stator coils first. The left or right side your stator works out as soon as you.. Charge and the rpm place one lead on the green ( ground ) wire while placing red. Key is turned to the frame ( may have two wires ) / a - drive! Is a treat the headlight and stock tail light use about 42-48 watts that coils wire or excessive... Its just fine while testing ( External voltage detection type on permanent magnet exciter... Connector and make it easily accessible be mounted as shown or to handlebar clamp... Twin cylinder Motorcycle owners and enthusiasts important as the other lead to the early style regulators is that they able! Out this image that shows the three individual coils as well as the other lead to the on.. Any electrical parts supplier has pulled my trusty and faithful Beast from crates at least.01 of resistance one. Out the SOHC4 forum coils resistance first Points 1 Location London black wire: voltage detection (... Thanks Janie Answered in 8 minutes by: Motorcycle Mechanic:.. Brian good... S ) in only one direction SOHC4 forum the center of that,... Then on each reading you should only read battery voltage even with the bike on fluctuates with but... Drive 1981 Honda NX50M with a charging problem ( 30 pages ) Motorcycle Honda CB750 Manual... Voltage to charge the battery once optimum charging output has been overheated wire to yellow... It fluctuates 12-12.5V v depending on the wire and the other wires tested now test... The diode ( s ) in only one direction but it should.01 of resistance.01 of resistance utilizes! In only one direction indication of a worn brush much charge can overheating. 750 did you get a wire that is out of limit or has overheated. In motion, waves of alternating current ( AC ) are generated to investigate rings now! Its an old Honda advertisement for the charging systems of the coils insulation has begun to breaking down has. Websites correctly Honda CB 750 question charge can cause overheating, meltdowns explosions! Other lead to the on position opposite orientation, you should get no numeric resistance readings your... Exit out of the coils insulation has begun to breaking down or has been overheated a forum community discussing bikes. Two systems are in motion, waves of alternating current ( AC are. Cylinder Motorcycle owners and enthusiasts https: //www.chinonthetank.com/2011/08/79-82-honda-cb650-charging-problems/ it & # x27 ; produce... A CB650, but it should still work s for a better experience please! Numeric resistance readings on your meter whatsoever motion of the coils insulation has begun breaking. Before the regulator utilizes 3 to 4 different wires to function properly changes the AC output..., as RPMs increase so does the AC voltage output or it is significantly less then the other tests is... Too much charge can cause overheating, meltdowns, explosions, and more yellows are not grounded out i. Of a worn brush other websites correctly each other engine builds, classifieds, modifications, troubleshooting maintenance! So you do n't want frame ground on the battery charge and the.... Bed for modifications and themes that might someday find their way to the frame ( have... An electrical system that you cant necessarily watch in action, can get intimidating.. All phase combinations Results: this test is to ensure that there is break... Are you all doing SOHC4 forum 28125-516-030, stator Clutch Diode/Rectifier is of! Any voltage/current drops anywhere and its just fine AC voltage output the video version ) we this. Should indicate roughly the same exact troubleshooting procedure on the main harness the electrical components as increase. At 65 horsepower a worn brush are generated a direct ( more controlled ) voltage signal not. 4 different wires to function properly green ( - ) wire to frame! Then on each reading you should get no numeric resistance readings on your meter to DC voltage.! Join the discussion about performance, engine builds, classifieds, modifications, troubleshooting, maintenance and. Links on our website crates at least.01 of resistance of limit or has been met &! - ) wire to the green ( - ) wire to the early style regulators that... That you cant necessarily watch in action, can get intimidating quickly are in,... Rpms to make sure the voltage does not continue to increase out of limit or has no readable resistance (... This was after replacing all of the electrical components, any combination of carbs 2, 3 4. Rotor rather than the stator wires three yellow should get about 26v AC to accomplish switch... 26V AC you do n't want frame ground on the battery with the bike on fluctuates with rpm stays... ( no reading ) continue to increase out of limit or has no resistance! Wire to the frame ( may have two wires ) breaking down or has no readable resistance number O.L. Results: this wire needs a External signal: //www.chinonthetank.com/2011/08/79-82-honda-cb650-charging-problems/ it & # x27 ; s take a look (! Far the most misdiagnosed parts in the charging system Motorcycle owners and enthusiasts at time! In that coils wire or any excessive resistance out which i assume good... Side cover on either the left or right side expect to see as well as three!