Test the AC voltage from the stator wires three yellow should get about 26v ac. Red or red/white wire: Battery voltage (may have two wires). *Results: Since each model bike has different specifications, be sure to check what your model specific manual. *Results: Since this wire needs a external signal. I have a 1975 Honda CB750. A good charging system would indicate a higher voltage read depending on the rpm. Log in SOHC/4 Forum Archives. If you get a resistance reading through both ways on the diode. So I've been working on my CB for the past few weeks in an attempt to get it to charge normally again. *Results: What you are looking for is a consistent AC voltage output reading from each leg of the stator. 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. Also Be sure to check out these videos that I have over on the YouTube channel! Changed voltage regulator - did not help. Im pulling my hair out. Good luck, old wiring sure is a treat. Check the harness for breaks, rusty corroded frame ground, or loose connections (battery terminals included) This can result in a high charging output to the battery and in some cases a no charge scenario. 2. I just checked for AC voltage from my coil before the regulator, and I was getting 1.0 vac at 5000 rpm. The Fora platform includes forum software by XenForo. Keep in mind that this process is happening faster then you can see. The CB450 alternator puts out about 110 watts when new. So I've owned this bike for about 4 months and it's had this issue from the beginning. you will do the same exact troubleshooting procedure on the green (ground) wire to the same three yellow 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. I HAVE A 81 HONDA CB 750. stop losing sleep!just check those resistances. The lights were bright with no fading based on the idle. Yeah man, test the rotor. im gonna hook the ac gen up to an oscilliscope and see wtf's goin on. Now reverse your leads and retest in the same manner as before. JavaScript is disabled. 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. You may also get a very high resistance reading. Rectifier-Regulator: This is a combination unit which will replace the OEM regulator and rectifier. I think the break even point for me (not charging or discharging) is around 3000-3500 rpms. 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. Remove C first, you may be able to see if the PO hacked into the original wiringLarry, Ok wiring is all good, from the stator and under the cover i have 3 yellow wires, green, white but also the neutral switch wire and the oil pressure wire. right ? Other then poor manufacturing or using cheap internal compounds, these stators heat up and cool down over and over through daily use. It had starting issues at the time. Thanks Janie Answered in 8 minutes by: Motorcycle Mechanic: .. Brian : Good day and welcome to Just Answer. VerticalScope Inc., 111 Peter Street, Suite 600, Toronto, Ontario, M5V 2H1, Canada. 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. Thanks. The Fora platform includes forum software by XenForo. Cold starting issue with 81' CB750. October 14, 2022, 04:29:16 AM. JavaScript is disabled. You will receive a reminder when the product becomes available 3. Any gurus around right now? Content on hondatwins.net is generated by its users. For a better experience, please enable JavaScript in your browser before proceeding. If all of the above checks out well, charge your battery, disconnect at the voltage regulator the stator harness that runs to it. We show up on loads of google searches now. HONDA cb750 charging system explained - YouTube AboutPressCopyrightContact usCreatorsAdvertiseDevelopersTermsPrivacyPolicy & SafetyHow YouTube worksTest new featuresNFL Sunday Ticket 2023. (The bike does not need to be running to do this test). Your alternator has to pass AC voltage before the rectifier/regulator can do its work. It fluctuates 12-12.5V v depending on the battery charge and the rpm. Locate the stators wire harness connector and make it easily accessible. enough is enough!. When I first got it, it ran great if started in hot weather. Just use your multi meter set on ohms, and see if it goes up to where the wring diagram says it should. For a better experience, please enable JavaScript in your browser before proceeding. Ill be waiting to hear from you before taking further action Why do you think your rotor is bad? Honda cb750 sport motorcycle owner's manual (90 pages) Rick's Electric Brand Lithium Ion Battery Compatible Rectifier-Regulator. There is a very effective way to see if your battery has any excessive draw on it while the key is off. It may not display this or other websites correctly. 0 Members and 1 Guest are viewing this topic. Use that. Like 850 outbound clicks to CB750C.com WEEKLY. JavaScript is disabled. I have measured voltage at battery POS and NEG. This had all of my factory resources and more. There are several available in the aftermarket though. For Honda, the wires are ALWAYS YELLOW in color. Motorcycle Honda CB750F2 Owner's Manual . In a correct wiring scheme, i should have 3 yellow wires coming for the stator, 1 green and 1 white ? Here is a video explaining this procedure. Apr 08, 2010 2003 Honda CB 750 Nighthawk. hondatwins.net is an independent Honda enthusiast website owned and operated by VerticalScope Inc. Motorcycle Honda Nighthawk CB 750 1991 Service Manual. This more than likely means that there is a break in the windings. i doused pretty much the whole bike in contact cleaner to no avail. Shop & Parts Manuals & Speciality Tools You must log in or register to reply here. 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). could be that, theoretically. Registered so I could say thanks, maybe do my part to keep it up. Honda CB750 (69-78) Rick's Electrics Complete Refurbished Charging Systems NEW Cycle X "High output 20 amp system" . The demons are repulsed when a man does good. Logo merchandise is available at the SOHC/4 Shop. Keeping money in your pocket from avoiding the shot-gun approach whenever a charging system problem arises. Here is a link to a CB 750 forum that covers the DOHC CB 750s. To little charge will gradually kill your battery. You are using an out of date browser. These wires exit out of the engines side cover on either the left or right side. You need to backtrack to the stator cover, remove left shift cover, and verify what wiring is there. JavaScript is disabled. Read full answer. So I bought a 1981 CB750 about a year ago. . Take note that in the center of that illustration, they are all connected to each other. Now I'm stuck. Found these a while back and the Admin over on CB750C.com gave me permision to share. Well let's take a look. The 3 male spade connectors plug in where the old regulator connected. 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. For a better experience, please enable JavaScript in your browser before proceeding. 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. 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. 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. Generally anything below 8mm is an indication of a worn brush. This charging problem started two weeks ago, and has managed to screw me pretty good. its incredibly simple! 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. 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. The voltage on the battery with the bike on fluctuates with RPM but stays significantly below the 14.5 I expect to see. How do I test the rotor? Talk to Tony at Oregonmotorcycleparts.com. Typically a standard circuit wire has at least .01 of resistance. Volt Amp Ohm meter with diode and continuity test, Alligator clips help add extra hands to your testing scenario. 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. i think my problem is in the rotor rather than the stator. I've done 2- 750's. Since the rectifier is made up of multiple one way valves, we need ensure that they are doing their individual jobs for the AC to DC switch. I'm having the same problem.. 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. Remember that your testing the actual regulator/rectifier harness this time, and not the main wire harness. Disconnect the stators wire harness connector. 1981 HONDA CB650Z / A - chain drive 1981 HONDA CB750F/F2 . This changes the AC wave to a direct (more controlled) voltage signal. The voltage on the battery with the bike on fluctuates with RPM but stays significantly below the 14.5 I expect to see. Let me explain. Anyway the DOHC CB 750s are known for really bad electrics. Messages 1 . 1. yes, that is correct, however be sure that you connect the other two wires, white and black. My battery is not fully charged right now, so I am guessing that would be part of the problem with only getting 10vac. 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. These Honda rotors have been upgraded for improved performance and reliability. High quality Part. 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 . HAVE A CHARGING PROBLEM. 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. I am thinking maybe my brushes are bad because 1 is a lot more worn down then the other. My CB 750 is not charging my battery while riding. 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. Whenever a charging system explained - YouTube AboutPressCopyrightContact usCreatorsAdvertiseDevelopersTermsPrivacyPolicy & amp ; SafetyHow YouTube worksTest new featuresNFL Sunday Ticket.. Good luck, old wiring sure is a combination unit which will replace the OEM regulator rectifier! Have a 81 Honda CB 750. stop losing sleep! just check those resistances excessive draw on while. Scheme, I 1981 cb750 charging problems have 3 yellow wires least.01 of resistance the windings AC! 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