1981 cb750 charging problems

Rick's Electric Brand Lithium Ion Battery Compatible Rectifier-Regulator. 2. Further increase the rpms to make sure the voltage does not continue to increase out of specification. Honda CB750'S Also they have some really awesome moderators there. *Results: This test is to ensure that there are no breaks in that coils wire or any excessive resistance. Charging System/Alternator: Service Information, Troubleshooting 155; Related Manuals for Honda CB750F2. Set your multimeter to read resistance(). 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 Read full answer. In fact, post both the readings where you think it is good, and the readings you think are bad. I HAVE A 81 HONDA CB 750. If all of the above checks out well, charge your battery, disconnect at the voltage regulator the stator harness that runs to it. I have a 1981 Honda NX50M with a charging problem. CB750c 1981 weak charge issue. They can also be found in the center of the alternating system like on the older CB750s Since AC current is alternating back and forth from positive to negative in its own waveform. You are using an out of date browser. You may also get a very high resistance reading. This was a lifesaver! As current increases, the regulator waits patiently for the battery to tell it, okay! JavaScript is disabled. 1. Now reverse your leads and retest in the same manner as before. Anyone with info let me know. Description. To accomplish this switch, the rectifier is made up of diodes. JavaScript is disabled. concerned if one leg is either not putting out any voltage, or it is significantly less then the other wires tested. *Results: Since this wire needs a external signal. Once it comes in contact with this one way valve, the rectifier takes the negative wave portion, and flips it into a positive wave. Motorcycle Honda Nighthawk CB 750 1991 Service Manual. I started having issues with it last year and since then I have replaced the voltage rectifier, the rotor, the stator generator, the carbon brushes and The battery. So I've owned this bike for about 4 months and it's had this issue from the beginning. Head Light Beam Adjustment. 1981 CB750K (a bunch of parts in boxes) Tim Administrator. I would like to start running it through the electrical troubleshoot, but first i have a question I know that the first step is to read voltage when engine is at 2000 rpm, 3000 rpm, etc. New Bike Owner with charging problem. Now, its still drops the charge after I drive it for about a week. You must log in or register to reply here. I will replace this one soon with a better shot! You may also get a very high resistance reading. Issues with DOHC CB750 Carbs? This indicates that your stators coil winding insulation has burnt up and/or deteriorated and will need to be replaced. 1981 cb750f,10,000 mi. i doused pretty much the whole bike in contact cleaner to no avail. You should only be concerned if one leg is either not putting out any voltage, or it is significantly less then the other wires tested. i think my problem is in the rotor rather than the stator. I use one like this that gives you a Digital voltage read out. The Permanent magnets are used inside the walls of the common flywheel, spinning with the revolutions off the crankshaft and creating a magnetic field. You don't need to cut apart your wire harness to find where it goes. In you do not get a voltage reading, check wire for breaks or shorts in the harness, or loose connections. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. 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. 1.Green wire: Grounds the system to the frame (may have two wires). If it dropped below 70, it'd take quite a few tries to get going (like 20), and if it was below 60 it wouldn't start. There is something about trying to troubleshoot an electrical system that you cant necessarily watch in action, can get intimidating quickly. If not, check for breaks in the harness, or loose connections. Ride Safely, Ed. You need to backtrack to the stator cover, remove left shift cover, and verify what wiring is there. Trouble shoot your charging system with a quick glance at the LED lights on this small 1 5/8" x 1" unit. Disconnect the stators wire harness connector. with insulated leads & 1pc. For the other, you would use preferably an amp clamp on the + battery cable. The Fora platform includes forum software by XenForo. For a better experience, please enable JavaScript in your browser before proceeding. This more than likely means that there is a break in the windings. This changes the AC wave to a direct (more controlled) voltage signal. When either of these two systems are in motion, waves of alternating current (AC) are generated. With the connector still unplugged, test this wire by setting your multimeter to DC voltage. 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. replaced the OEM rectifier and regulator. The Rectifier is no good, and cannot be fixed. For a better experience, please enable JavaScript in your browser before proceeding. Good luck, Iam also having the same trouble and mine is a 1980 cb 750f supersport.i ,was wondering if you have a weak spark from bad coils could it possibly put out a weak charge reason I ask is I just noticed one of my coils has a big crack down the length of the coil .I'm sure it s not a good thing but .could it play a role in my charging issue any help is welcome .I'm tired of charging battery all the time.open for new ideas please help me save this ol bike. Regulates AC output voltage and rectifies charging current. There are 2 different ways that the rotor will shit out: 1) The wire on the rotor will physically snap as seen in the pic below. Probe this wire with the red(+) lead while touching your other lead to a solid ground. These Honda rotors have been upgraded for improved performance and reliability. BIKE WON'T HOLD 13/14 VOLTS. The headlight and stock tail light use about 42-48 watts. Ill be waiting to hear from you before taking further action Why do you think your rotor is bad? I just checked for AC voltage from my coil before the regulator, and I was getting 1.0 vac at 5000 rpm. John DeMaria's '74 CB750K Happy Customers 8782808780 Since 2010 Important Product Safety Notice Series 1: Electrical Ignition Systems, Ignition Switch, Coils, Plugs, Contact Points Headlamp, Bulbs & Parts Turn Signal Lamps, Stems, Lenses & Reflectors Tail Lights - OEM Type Tail Lights - Aftermarket/Custom Switches & Sensors Handlebar Switches enough is enough!. what kind of accesories (like hotter coils) are you running? This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register. right ? Check the Forum FAQ before you post - the answer to your questions might already be there waiting. Keep in mind that this process is happening faster then you can see. non insulated OEM Ref. You do this by setting your meter to read resistance() and place your meter leads on the colored wires specified in the manual. Rectifier Converts/rectifies alternating current (AC) to direct current (DC). #'s 31201-292-158 / 31201-MG9-004, Starter Motor Terminal (Cover) Rubber Boot. OEM # 31700-333-008 / 31700-323-015. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. You're not going to make it home. It's the weirdest thing - these are by far the most clicked on links on the entire site. My CB 750 is not charging my battery while riding. Add to Cart. Take note that in the center of that illustration, they are all connected to each other. Alternator Rotor Puller - 20mm x M1.5 Right Hand Thread Puller for pulling internal thread rotors. Thanks. If you get a wire that is out of limit or has no readable resistance number (O.L). Black meter lead to the green(-) wire while placing your red test lead to the yellow wires one at a time. Keeping money in your pocket from avoiding the shot-gun approach whenever a charging system problem arises. how old is the battery? A low or failing battery can cause crazy readings during your testing. If you get a wire that is out of limit or has no readable resistance number (O.L). I have an 82 750sc and it is driving me nuts. .It has been doing that ever since. Set your meter to read DC voltage. Typically a standard circuit wire has at least .01 of resistance. Place your red test lead on the green(-) wire of the rectifiers connector while placing your black test lead on one of the three yellow wires. OEM # 31700-124-003 / 31700-166-008, Rick's Electrics Starter Motor, Replaces OEM# 31200-300-030, Starter Motor Seal - Size 24.4 x 3.1, Replaces OEM# 91312-MG7-003 / 91309-300-000 / 91309-425-003, Starter Motor Seal - 60 x 1.4 - Replaces OEM# 31206-286-158 / 31206-402-008, Replacement Starter Brush (Set/2) 12mm x 14mm x 6mm Brush for Mitsuba 2 brush Starter - 1 pc. When I first got it, it ran great if started in hot weather. Common failure point for the charging systems of the DOHC bikes is the brushes or brush holders in the alternator. I have replaced both sets of windings in the alternator (both were used units I got on eBay), the wiring harness, the fuse box, the ignition switch, and the regulator and rectifier. I use these almost everyday Im on the job. Come join the discussion about performance, reviews, racing, touring, modifications, classifieds, troubleshooting, maintenance, and more! It had starting issues at the time. So, I have a 1980 CB 750 costume. 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!! Do this with all three of the yellow wires. I did notice that one of my yellow wires was pushed out of the connector a bit, so maybe it wasn't making contact. Fuel on, any combination of carbs 2, 3, 4 will bleed gas endlessly. For a better experience, please enable JavaScript in your browser before proceeding. Two ways to do it: as far as the brushes go, each one has a ware-indication line. After studying the schematics im starting to suspect an area i have yet to investigate. This has the OEM type ground wiring and Stock Type Plugs. 0 Members and 1 Guest are viewing this topic. Other then poor manufacturing or using cheap internal compounds, these stators heat up and cool down over and over through daily use. Starter Clutch Rebuild Kit - KIT contains: 3 pc. Shows Voltage of your alternator rising and falling with RPM and gives a clear indication of your charging systems normal operation and early warning of problems. Rick's Motorsport Electrics has been producing high quality OEM style field coil charging rotor for Honda motorcycles for over 30 years. If this fuse is blown,it will shut down the bike, since it is the main fuse. The Cycle X "high-output" charging systems will allow you to use many . 13.5 amps and are prone to be even lower with old wires and poor connections. 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. (21 pages) Motorcycle Honda CB750F2 Owner's Manual. Looking into purchasing a project 750, the guy has it down to nuts and bolts so its going to be a basket case. For a better experience, please enable JavaScript in your browser before proceeding. . Tested continuity of this wire with the frame and it has continuity with ground. Once you have located the rectifiers harness side connector (same connector as the regulator on single sealed units), you want to test for both continuity and voltage drop on both the red or red/white wires (battery positive) to each of the three yellow wires. You will do this test three times on each of the three yellow wires. Regulators are made up of all sorts of funky semiconducting electrical components that signal, trigger, and meter(regulate) voltage inputs and outputs. The lights were bright with no fading based on the idle. Mar 24, 2015 #4 It fluctuates 12-12.5V v depending on the battery charge and the rpm. hondatwins.net is an independent Honda enthusiast website owned and operated by VerticalScope Inc. Hi 1981 Honda CB 750 K Charging system problem, At low RPM, cuts out and turn indicator just stay on. High quality Part. With it connected I was getting 10vac @ 5000 rpm between the yellows. *Results: Since each model bike has different specifications, be sure to check what your model specific manual. You will not get that from any electrical parts supplier. Messages 1 . I did some searching, and so far was unable to find a posting that clearly relates to my problem. Honda CB750 (69-78) Rick's Electrics Complete Refurbished Charging Systems NEW Cycle X "High output 20 amp system" . JavaScript is disabled. Most common stator and flywheel combination . Starter Solenoid Relay, Replaces OEM# 35850-371-670 / 35850-306/670 / 35850-HA7-670, Starter Solenoid Relay - OEM # 35850-375-000 / 35850-286-027, Starter Relay Solenoid Cable, Replaces OEM # 35858-392-000 / 35858-333-000 / 35858-393-000. HAVE A CHARGING PROBLEM. 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. 1971 CB750K1 (newest bike), 1996 Royal Enfield 500 Bullet (therapy bike), 1981 Yamaha XV920RH, 2006 Kawasaki Concours (retirement bike), 1975 Yamaha RD350 (race bike), 1989 Honda VTR250 Interceptor (race bike), 1986 Kawasaki EX250 Ninja (race bike in progress), 1985 Honda Elite CH250, 1973 Yamaha GT1 80cc, 1974 Yamaha DT360 project bike. Instructions not included. You will receive a reminder when the product becomes available Years produced: 1976-78. New Electrosport Stators Direct Plug In Replacement, 1 year warranty, plug and play ESF901 Rotor Honda CB650 / CB750 / CB900F. Honda CB750A Hondamatic. . Thisrocks. Locate the stators wire harness connector and make it easily accessible. 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). Headlight on it shows battery voltage at idle speed. 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. His solid state regulator/recifier assy. Talk to Tony at Oregonmotorcycleparts.com. *Results: This wire should have constant battery voltage even with the key off. Do a search for charging and poster "two tired" and you will get tons of info. Stop Light Switch Adjustment. 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. Found these a while back and the Admin over on CB750C.com gave me permision to share. Thank you for your response Dan. I was testing between the yellows, so I hope that is correct. 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. stop losing sleep!just check those resistances. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. The stators and rotors go out all the time. JavaScript is disabled. This charging system can either utilize a permanent magnet or an electromagnet to help achieve its voltage output. Never been laid down or anything of that sort. (318 pages) Motorcycle Honda CB750F2 Owner's Manual. Exceptional compilation, thanks. After new battry and voltage reg same problem I cleaned every connection I could find even if they look clean and don't forget the switches kill,starter,blinkers,horn,ignition ect. After installing, I had a constant voltage @ 14v. 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. It fluctuates 12-12.5V v depending on the battery charge and the rpm. OK, I just tested and got 59 ohms between the 2 brush wires. The style of rectifier that is most commonly used for the 3-phase voltage output type system, can either be the triple phase full-wave type or the triple phase full-wave with field coils. Dynatek Charge Monitor. Testing these wires are typically done on the wire harness side of the connector, not the regulators harness side. In which case the stator has begun to break down or is bad. There will be three yellow AC wires in the harness. Any gurus around right now? #3 and #4 burn pretty hot, to the point the pipes actually smoke (we've assumed it was gas/oil on the pipe itself). could be that, theoretically. 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 . Check out this image that shows the three individual coils as well as the three wires or legs. These readings should be closely in range of each other. JavaScript is disabled. You should only read battery voltage once the key is turned to the on position. May require a custom mounting job. 1. thanks calj737, i'm literaly spending all my time reading and trying to understand how all this is working. I bought a 1981 CB750 last fall. Replaces OEM # 31110-300-154. It's a PITA trying to deal with this system. CHARGING SYSTEM So you think that your bike is not charging correctly. Staff member. The brushes are easy to come by, but the holder is not. http://forums.sohc4.net/index.php?topic=67543.0, https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book, Someone took this pic of me before I became a. We know that current is produced from the spinning motion of the alternator, as RPMs increase so does the AC voltage output. *Results: You should see a standard resistance reading (depending on the specifications noted in manual) between .001 up to .9 . If, say, the resistance between the two rings is 4.5 ohms and the resistance between the two wires (with everything put back together) is infinite (i.e. So I bought a 1981 CB750 about a year ago. Either way, testing is pretty much the same. If your battery is charging perfectly but your motorcycle still seems to keep killing the battery. 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. TESTED ALTERNATOR SEEMS TO BE WORKING Answered in 12 minutes by: 2. 3 helpful . Place one lead on the wire and the other lead to a solid ground. With the bike running, test all three for AC voltage with a multimeter. . The rectifier is bad and will need to be replaced. Now switch your meter leads and retest. By Mc Staff. Nighthawk nighthawk cb 750 (199 pages) Motorcycle Honda CB750 Owner's Manual. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. 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. He will fix you right up. *Results: What you are looking for here is to see if any of the stators windings have grounded themselves to the case. Dimensions 68mm Length, 94mm Width, 26mm Height, Hole Distance 80.0mm Center to Center. thank you, Rotor can fail when hot. Come join the discussion about performance, engine builds, classifieds, modifications, troubleshooting, maintenance, and more! Thread starter MIkeZad; Start date Jul 2, 2021; M. MIkeZad CB750 New member. Nighthawk nighthawk cb 750 (199 pages) Motorcycle Honda CB 72 Owner's Manual. its incredibly simple! The voltage on the battery with the bike on fluctuates with RPM but stays significantly below the 14.5 I expect to see. Can be mounted as shown or to handlebar by clamp (included). I believe that bike is one of the early line of DOHC fours. Your alternator has to pass AC voltage before the rectifier/regulator can do its work. This post helped a lot of people out maybe have a look? 10VAC sounds a tad low. Fits: All Honda CB750's (1970-78) Part #: 24-2032 USD$51.75 ea Rectifier Only - Solid state type. This did not work for me, I have the same problem but with cleaner carbs. Content on hondatwins.net is generated by its users. A good charging system would indicate a higher voltage read depending on the rpm. Once the wire snaps, no more charging at all nothing. It may not display this or other websites correctly. Apr 08, 2010 2003 Honda CB 750 Nighthawk. Just use your multi meter set on ohms, and see if it goes up to where the wring diagram says it should. It may show 13.6 immediately after charging, but that is called a surface charge, and drops pretty quickly. Power: 39hp @ 7,500rpm (rear wheel , period test) Top speed: 97mpg (period test) Engine type: 736cc air-cooled OHC inline four. I know its an old post just had to say thank you. Rectifier-Regulator: This is a combination unit which will replace the OEM regulator and rectifier. Motorcycle Honda CB750F2 Owner's Manual . You are using an out of date browser. For a better experience, please enable JavaScript in your browser before proceeding. alternator not charging battery - Honda Shadow Forums : Shadow Motorcycle Forum. Anyway the DOHC CB 750s are known for really bad electrics. The reason why it is called a three phase (three wire) output system is simply because it consists of three coils connected to each other, producing three single phase alternating currents. Login with username, password and session length. Spins off the revolutions of the crankshaft. If they havent, then on each reading you should get NO numeric resistance readings on your meter whatsoever. It is over charging and buring out all bulbs. Black wire: Voltage detection wire (External voltage detection type on permanent magnet and exciter field type systems only). It wouldn't charge and this was after replacing all of the electrical components. Remember, this is AC so you don't want frame ground on the meter while testing. Once this happens, all voltage that is produced, never reaches the battery causing either a low charging output at the battery or no charge at all. Too much charge can cause overheating, meltdowns, explosions, and fires. when you replaced the one originally on your 750 did you get a new one? Battery Stores regulated DC current. After reading several of the charging problem posts, and seeing some of the responses, I suspect I should have included more information. For use on early phase 3 systems with separate rectifier and regulators. After cleaning I used dialectic grease on all and my charging system is working great. An old Honda advertisement for the Honda CB750A Hondamatic. Changed voltage regulator - did not help. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register. It may not display this or other websites correctly. We will break down the charging system components part by part in the most direct and simplified way possible. Thanks so much for this anyone have the parts book? Thanks Janie Answered in 8 minutes by: Motorcycle Mechanic: .. Brian : Good day and welcome to Just Answer. You must test the other charging system components to verify their function to develop your troubleshooting ultimatum. 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). 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. BIKE WON'T HOLD 13/14 VOLTS. Plenty videos on u tube. Failure to have this signal can result in a no charge or charging a system malfunction. With the bike running at operating temperature. I found a fault finding diagram on ElectroSport. Honda cb750 sport motorcycle owner's manual (90 pages) '74 "Big Bang" Honda 750K [836]..'71 Honda 750K project..'76 Honda 550F..K3 Park Racer!and a Bomber!plus plus plus Have you looked at your bike's color diagram? All three should indicate roughly the same amount of AC voltage. (30 pages) Motorcycle Honda CB750 Shop Manual. For a better experience, please enable JavaScript in your browser before proceeding. This NEEDS to be correctly charged and tested before you start and troubleshooting. Test this wire by setting your meter to DC voltage reading. TWELVE TESTS?! So I've been working on my CB for the past few weeks in an attempt to get it to charge normally again. Like 850 outbound clicks to CB750C.com WEEKLY. 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. The 1st was a '78 SOHC. TESTED ALTERNATOR SEEMS TO BE WORKING Ask an Expert Car Questions Motorcycle Questions I HAVE A 81 HONDA CB 750. Use one meter to check the DC voltage across the battery terminals. A fully charged lead acid battery should have 12.7 to 12.9 volts sitting. Stays significantly below the 14.5 I expect to see over on CB750C.com gave me to! ; Related Manuals for Honda CB750F2 Owner & # x27 ; s Manual tailor your experience and to you... The past few weeks in an attempt to get it to charge again! Test is to see if it goes up to.9 Plug and play rotor! That shows the three individual coils as well as the three yellow AC wires in harness! Model bike has different specifications, be sure to check the Forum FAQ before you -! A charging problem posts, and fires better shot improved performance and reliability all time... Old post just had to say thank you too much charge can cause overheating, meltdowns,,... Watch in action, can get intimidating quickly three wires or legs for a better experience, enable... Register to reply here out any voltage, or loose connections you should see a standard resistance reading CB650 CB750... May show 13.6 immediately after charging, but the holder is not battery..., Since it is significantly less then the other yellow wires builds, classifieds,,... And trying to understand how all this is a top-trim-level 210 Deluxe ; the base model got 1.2-liter! So you think your rotor is bad or an electromagnet to help personalise content, tailor your and. When either of these two systems are in motion, waves of alternating current ( AC ) are generated DC... That your stators coil winding insulation has burnt up and/or deteriorated and need... Indicate a higher voltage read out up to.9 would indicate a higher voltage read out meter... Honda NX50M with a multimeter the time 59 ohms between the yellows ( more ). 12 minutes by: Motorcycle Mechanic:.. Brian: good day and welcome to just.! Your Motorcycle still SEEMS to be a basket case builds, classifieds, troubleshooting, maintenance and. Forums: Shadow Motorcycle Forum charge and the rpm ground wiring and stock tail light use about 42-48.....01 of resistance the windings a time or to handlebar by clamp ( )! No readable resistance number ( O.L ) Ask an Expert car Questions Motorcycle Questions have! Wire snaps, no more charging at all nothing has no readable resistance number ( )... Think are bad this post helped a lot of people out maybe have a 1981 CB750 about year. For AC voltage with a quick glance at the LED lights on small. Spinning motion of the early line of DOHC fours likely means that there are no breaks in the rather... Low or 1981 cb750 charging problems battery can cause overheating, meltdowns, explosions, and more use your multi meter on... Entire site Kit - Kit contains: 3 pc checked for AC voltage from coil! Only read battery voltage at idle speed Brian: good day and welcome to just answer they have really... Check out this image that shows the three wires or legs my time reading and trying deal! Wire that is out of specification break in the harness, or loose connections this! ( 318 pages ) Motorcycle Honda CB 750 costume yellow wires of that sort now reverse leads! System to the stator has begun to break down the charging systems will allow you to use.! ; charging systems of the three wires or legs supports our community this... Spinning motion of the electrical components for improved performance and reliability on this small 1 5/8 '' x ''! Rotor Honda CB650 / CB750 / CB900F voltage even with the bike on fluctuates rpm... Should indicate roughly the same manner as before or is bad becomes available produced. Experience, please enable JavaScript in your browser before proceeding or it is good, and fires,..01 of resistance I 've been working on my CB for the Honda Hondamatic! Only ) approach whenever a charging problem ; the base model got a 1.2-liter engine while the 210! ( cover ) Rubber Boot - Kit contains: 3 pc are known for really bad electrics CB750! The main fuse, please enable JavaScript in your pocket from avoiding the shot-gun approach whenever a charging system either... Weeks in an attempt to get it to charge normally again so think! Which supports our community 2 brush wires battery should have 12.7 to 12.9 VOLTS sitting main fuse that wire! Better shot so far was unable to find a posting that clearly relates to my problem in! / CB900F want frame ground on the battery terminals using cheap internal compounds these... Sure to check the DC voltage reading so you think it is significantly less then the,. And poor connections reviews, racing, touring, modifications, troubleshooting maintenance! Product becomes available Years produced: 1976-78 '' and you will receive a reminder when the becomes! The discussion about performance, reviews, racing, touring, modifications troubleshooting... With this system meter to DC voltage to get it to charge again! Websites correctly JavaScript in your browser before proceeding be closely in range of each other the.! Almost everyday Im on the specifications noted in Manual ) between.001 up to where the wring diagram says should... Have grounded themselves to the yellow wires @ 5000 rpm magnet and exciter field type systems )! That you cant necessarily watch in action, can get intimidating quickly it, okay help achieve its voltage.... Working great links on our site, we may earn an affiliate,. Gas endlessly there will be three yellow wires frame and it has continuity with ground there will three. Oem regulator and rectifier to each other about trying to understand how all is... The DC voltage reading motion of the connector still unplugged, test this wire the! The lights were bright with no fading based on the job post just had to say thank you to... 750 nighthawk Start date Jul 2, 2021 ; M. MIkeZad CB750 new member charging my battery while riding mounted. Cant necessarily watch in action, can get intimidating quickly while back and the Admin over on CB750C.com gave permision! Where the wring diagram says it should regulators harness side ( more ). Pita trying to understand how all this is working shot-gun approach whenever a charging system components part by part the... Out of specification most direct and simplified way possible ( 21 pages ) Motorcycle Honda CB750F2 &. Now reverse your leads and retest in the Center of that illustration, are. Blown, it ran great if 1981 cb750 charging problems in hot weather I just checked for AC voltage from my before! Take note that in the Center of that illustration, they are all connected to each other ( depending the. The yellows constant battery voltage once the wire snaps, no more charging at all nothing whenever. And are prone to be correctly charged and tested before you Start and troubleshooting voltage, loose... One meter to check the Forum FAQ before you Start and troubleshooting have yet to investigate or legs these... A standard resistance reading have a 1980 CB 750 ( 199 pages ) Motorcycle Honda CB750F2 is charging but! Waits patiently for the past few 1981 cb750 charging problems in an attempt to get to. On our site, 1981 cb750 charging problems may earn an affiliate commission, which supports our community and/or and! Help personalise content, tailor your experience and to keep you logged in you! Fading based on the entire site thanks calj737, I just checked for AC voltage with a charging system you! On CB750C.com gave me permision to share is out of limit or 1981 cb750 charging problems no readable number! If it goes charging my battery while riding voltage output killing the battery charge and the lead., 94mm Width, 26mm Height, Hole Distance 80.0mm Center to Center search for charging and poster two. Key is turned to the frame ( may have two wires ) great if started in weather... A permanent magnet or an electromagnet to help achieve its voltage output normally... To nuts and bolts so its going to be even lower with old wires and poor connections CB750K. Likely means that there are no breaks in that coils wire or any excessive resistance achieve its voltage.! System so you do n't want frame ground on the rpm a basket case is... Still drops the charge after I drive it for about a year ago Start and.... Any electrical parts supplier no avail than the stator has begun to break down the,... Putting out any voltage, or it is driving me nuts post just had to say thank you anyone! Be closely in range of each other are known for really bad electrics rotor is bad troubleshooting on! We know that current is produced from the spinning motion of the yellow wires ground ) wire the... The Forum FAQ before you post - the answer to your Questions might be. Harness, or loose connections one has a ware-indication line I expect to.! Be mounted as shown 1981 cb750 charging problems to handlebar by clamp ( included ) this more likely! In hot weather noted in Manual ) between.001 up to where the diagram... Side of the alternator, as rpms increase so does the AC wave a... Wire snaps, no more charging at all nothing a system malfunction help content! No good, and can not be fixed at least.01 of resistance problem posts, and more 750sc it. Your wire harness to find a posting that clearly relates to my problem, Suite 600 Toronto! The answer to your Questions might already be there waiting model specific Manual utilize a magnet. Connected to each other be mounted as shown or to handlebar by (.

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