Generally anything below 8mm is an indication of a worn brush. Stop Light Switch Adjustment. I use these almost everyday Im on the job. could be that, theoretically. Thanks so much for this anyone have the parts book? JavaScript is disabled. 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). I'm having the same problem.. With it connected I was getting 10vac @ 5000 rpm between the yellows. This needs to be 12.5volts or above for accurate testing results He will fix you right up. If it doesn't then you might have to start tracing physically. Yeah man, test the rotor. Submit. It is caused by the charging system surging. Locate the stators wire harness connector and make it easily accessible. 4. enough is enough!. CB750c 1981 weak charge issue. A fully charged lead acid battery should have 12.7 to 12.9 volts sitting. (30 pages) Motorcycle Honda CB750 Shop Manual. You need to backtrack to the stator cover, remove left shift cover, and verify what wiring is there. This NEEDS to be correctly charged and tested before you start and troubleshooting. This indicates that your stators coil winding insulation has burnt up and/or deteriorated and will need to be replaced. Let me explain. I think the break even point for me (not charging or discharging) is around 3000-3500 rpms. Black wire: Voltage detection wire (External voltage detection type on permanent magnet and exciter field type systems only). Dynatek Charge Monitor. http://www.bikeexif.com/honda-cb450-restoration. Since AC current is alternating back and forth from positive to negative in its own waveform. 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. October 14, 2022, 04:29:16 AM. Read full answer. Place your red(+) lead to one of the yellow stator wires and place the other lead to a different yellow wire in the connector. (318 pages) Motorcycle Honda CB750F2 Owner's Manual. CruiserForums Moderator - Route 66 / American Iron / The Clinic Forums. There is a very effective way to see if your battery has any excessive draw on it while the key is off. From the main harness, i have the green, white and black as single wires that would go to the regulator then i have my big plug that should go to the rectifier with 3 yellow, 1 red and another red instead of green!! when you replaced the one originally on your 750 did you get a new one? So I bought a 1981 CB750 about a year ago. This post helped a lot of people out maybe have a look? #'s 31201-292-158 / 31201-MG9-004, Starter Motor Terminal (Cover) Rubber Boot. 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. Ok, my previous post jumped ahead in the troubleshooting process, assuming you or your Mech had done these initial tests. hondatwins.net is not in any way affiliated with Honda Motor Company, VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. 0 Members and 1 Guest are viewing this topic. In which case the stator has begun to break down or is bad. Rectifier Converts/rectifies alternating current (AC) to direct current (DC). JavaScript is disabled. thanks calj737, i'm literaly spending all my time reading and trying to understand how all this is working. 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. You don't need to cut apart your wire harness to find where it goes. , Pre 1980, some bikes used these two systems as separated units. Thread starter MIkeZad; Start date Jul 2, 2021; M. MIkeZad CB750 New member. Any insights would be greatly appreciated. Replacing Light Bulbs. BIKE WON'T HOLD 13/14 VOLTS. A low or failing battery can cause crazy readings during your testing. Exceptional compilation, thanks. 22v at idle up . Charging System/Alternator: Service Information, Troubleshooting 155; Related Manuals for Honda CB750F2. The stator needs to be replaced. Wez_ C. Reg/rec . I've done 2- 750's. Good luck, old wiring sure is a treat. They are not serviceable, and if a problem is found with either systems. CHARGING SYSTEM So you think that your bike is not charging correctly. It will instantly start draining the battery. Nighthawk nighthawk cb 750 (199 pages) Motorcycle Honda CB 72 Owner's Manual. Motorcycle Honda Nighthawk CB 750 1991 Service Manual. Unless they're both open circuits, you can verify that the brushes are contacting the rings if both resistance measurements are pretty much the same. after checking your resistance, check your ac output also lol Quote from: Stev-o on January 14, 2018, 03:07:12 pm, https://www.youtube.com/watch?v=F-Bw9xz09FU, Quote from: aminemed on January 14, 2018, 02:44:23 pm, http://forums.sohc4.net/index.php?topic=126401.0, http://forums.sohc4.net/index.php?topic=132935.0, https://www.cmsnl.com/classic-honda-fansite/honda_wiring_diagrams/CB750(K3-K7).jpg. It fluctuates 12-12.5V v depending on the battery charge and the rpm. You three yellow wires will output AC voltage in the range of 30-70V ac test them with your multi meter set on 200vac and check the combination of three wires, between any and all of them, in pairs. Typically a standard circuit wire has at least .01 of resistance. 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. The Fora platform includes forum software by XenForo. Ride Safely, Ed. Rick's Motorsport Electrics has been producing high quality OEM style field coil charging rotor for Honda motorcycles for over 30 years. The voltage on the battery with the bike on fluctuates with RPM but stays significantly below the 14.5 I expect to see. This has the OEM type ground wiring and Stock Type Plugs. Dimensions 68mm Length, 94mm Width, 26mm Height, Hole Distance 80.0mm Center to Center. Other random wires: If your system is designed with an additional field coil (refer to model specific service manual) it will need to be tested as well. Your right about the holder. Some more pics, checked everything again: After reading in the forum, it seems that the first issue to check if my battery voltage is not increasing with the rpm is the alternator. Here is a link to a CB 750 forum that covers the DOHC CB 750s. Mine still doesn't produce enough voltage to charge the battery below 2,000rpm. Head Light Beam Adjustment. Staff member. i think my problem is in the rotor rather than the stator. This is a combination unit which will replace the OEM regulator and rectifier; stock type plugs and installation instructions are included. Here is a video explaining this procedure. It's a PITA trying to deal with this system. You're not going to make it home. It may not display this or other websites correctly. So I've been working on my CB for the past few weeks in an attempt to get it to charge normally again. I did some work over the winter, including: New battery Replaced a bad stator New regulator/rectifier After all of this, I placed the battery on a charger overnight and. Returning back to DTT it puts a smile on my face to read these posts from my old thread. 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. I will go pull the cover now and test the contact rings directly now. At the first start, assuming it's set over about 4 hours it takes forever to start. Keeping money in your pocket from avoiding the shot-gun approach whenever a charging system problem arises. Cycle Forums: Motorcycle and Sportbikes Forum. You will receive a reminder when the product becomes available, Ignition Systems, Ignition Switch, Coils, Plugs, Contact Points, Turn Signal Lamps, Stems, Lenses & Reflectors. CB750 charging problem HELP!! Anyone? You do this by setting your meter to read resistance() and place your meter leads on the colored wires specified in the manual. Good luck D Darryl thompson CB750 New member Messages 4 Reaction score 0 Points 1 Location Madras or 97741 Aug 21, 2022 #3 Add to Cart. Unplug your regulator/rectifiers harness connector and check for this wires continuity to ground. I checked them. With the bike running, test all three for AC voltage with a multimeter. I had a similar problem with my 750. 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. I need to look somewhere else to find my issue. You should only read battery voltage once the key is turned to the on position. 3. The 3 male spade connectors plug in where the old regulator connected. I have also checked all the wires terminals at it all seems to be just fine. So I've owned this bike for about 4 months and it's had this issue from the beginning. We will break down the charging system components part by part in the most direct and simplified way possible. A diode in its simplest form, is considered to be a one way valve for electricity. Then you can test the yellow wires. Bear in mind, this is theoretical knowledge being applied. Dan. Come join the discussion about performance modifications, troubleshooting, maintenance, and more! HAVE A CHARGING PROBLEM. . Honda CB750 (69-78) Rick's Electrics Complete Refurbished Charging Systems NEW Cycle X "High output 20 amp system" . Can be mounted as shown or to handlebar by clamp (included). For Honda, the wires are ALWAYS YELLOW in color. This can be an indication of the coils insulation has begun to breaking down or has been overheated. 2. Thanks. alright. http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter01GeneralInformation.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter02Lubrication.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter03InspectionandAdjustment.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter04FuelSystem.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter05EngineRemovalandInstallation.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter06CylinderHeadValve.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter07CylinderPiston.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter08Clutch.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter09GearshiftLinkage.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter10Crankcase.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter11Transmission.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter12CrankshaftPrimaryShaft.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter13FrontWheelSuspension.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter14RearWheelSuspension.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter15HydraulicBrake.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter16BatteryChargingSystem.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter17IgnitionSystem.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter18ElectricStarter.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter19Switches.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter20TechnicalFeatures.pdf, http://www.cb750c.com/publicdocs/CB750_Manual//Honda1979thru83CB750ServiceManualChapter21Troubleshooting.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter221979CB750KFAddendum.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter231980CB750KFAddendum.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter241980CB750CAddendum.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter251981Addendum.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter261982Addendum.pdf, http://www.cb750c.com/publicdocs/CB750_Manual/Honda1979thru83CB750ServiceManualChapter2782CB900SCAddendum.pdf, http://www.cb750c.com/publicdocs/CB750K_wir_diag/Wiring_Diagram_CB750K_79___.pdf, http://www.cb750c.com/publicdocs/CB750K_wir_diag/Wiring_Diagram_CB750K_79LTD.pdf, http://www.cb750c.com/publicdocs/CB750K_wir_diag/Wiring_Diagram_CB750K_80___.pdf, http://www.cb750c.com/publicdocs/CB750K_wir_diag/Wiring_Diagram_CB750K_81_82.pdf, http://www.cb750c.com/publicdocs/CB750K_wir_diag/Wiring_Diagram_CB750C_80___.pdf, http://www.cb750c.com/publicdocs/CB750K_wir_diag/Wiring_Diagram_CB750C_81_82.pdf, http://www.cb750c.com/publicdocs/CB750K_wir_diag/Wiring_Diagram_CB750F_79_80.pdf, http://www.cb750c.com/publicdocs/CB750K_wir_diag/Wiring_Diagram_CB750F_81_82.pdf, http://www.cb750c.com/publicdocs/CB750K_wir_diag/Wiring_Diagram_CB750SC_82__.pdf. Content on hondatwins.net is generated by its users. Test the resistance between the two wires on the connector, then take the alternator cap off and test the resistance between the two rings on the rotor. LED Charging system indicator Gauge. Sbartram91; Jun 10, 2020; Electrical; Replies 14 Views 4K. Cylinders #1 and #2 have spark, but will not burn. Rollers (15 x 13), Starter Clutch Roller Spring, Replaces OEM # 28125-516-030, Stator Clutch Diode/Rectifier. Now I'm stuck. 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. When either of these two systems are in motion, waves of alternating current (AC) are generated. This changes the AC wave to a direct (more controlled) voltage signal. We also know that in order for a battery to maintain and drain its usable energy over and over again, It needs to be charged. 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). We've updated our prices to Euro for your shopping convenience. I really hope mine isn't. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Sep 4, 2020. When you switched the leads in the opposite orientation, you should see an open (no reading). After cleaning I used dialectic grease on all and my charging system is working great. Rectifier Only - 3 phase - 5 Wire - 3 AC in - 2 DC out. That means this car is a top-trim-level 210 Deluxe; the base model got a 1.2-liter engine while the gas-sipping 210 MPG . You can do this test by first setting your multimeter to read AC voltage. 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. Cold starting issue with 81' CB750. I just checked for AC voltage from my coil before the regulator, and I was getting 1.0 vac at 5000 rpm. Failure to have this signal can result in a no charge or charging a system malfunction. TESTING REGULATOR FUNCTION AT THE BATTERY. Rick's Electric Brand OEM Style Honda Rectifier-Regulator: This is a combination unit which will replace the OEM regulator and rectifier; stock type plugs and installation instructions are included. His solid state regulator/recifier assy. Honda cb750 sport motorcycle owner's manual (90 pages) The Fora platform includes forum software by XenForo. its incredibly simple! JavaScript is disabled. Or other websites correctly remove left shift cover, and if a problem is found with systems... 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Or failing battery can cause crazy readings during your testing diode in its simplest form, is considered be... Will fix you 1981 cb750 charging problems up / 31201-MG9-004, Starter Motor Terminal ( cover ) Rubber Boot a fully lead! 4 hours it takes forever to start tracing physically has begun to down!