Comments on: 79-82 Honda cb650 charging problems

By: Erik

Erik — Tue, 07 Sep 2021 20:24:56 +0000

Power consumption is an important component. I renewed the rotor stator regulator and the battery, and still it drained the battery after 1-2 hours of driving. Ground cable, + cable renewed was of no use. The problem ended up being the wiring from the taillights. There are so many bad plugs … everything renewed, drove 6 hours today, city, country … arrived at home 13 V open circuit voltage (AGM battery) Also check your plugs, best of all and renew all plugs at the back of the light. The crimps were also bad there.

By: William Davis

William Davis — Thu, 02 Sep 2021 02:33:27 +0000

Wow, it looks like everyone with one of these has the same issue I do. Has anyone tried to use an LED light that runs LESS than 35 watts? They are super bright, and should use closer to 5-10 watts, maybe even less depending on the light. I have even considered (am still actively considering) adding solar someplace to try to take some load off the charging system, adding another battery someplace to assist with getting stuck and reduce the likelihood it gets low before I plug in the maintainer at home, I see someone else thought of ventilation and I have some marine clamshells I could install on the case to ventilate. These are shaped like scoops and are in stainless steel. I got them on Amazon for my boat. This is a major issue because I get 6 months to a year then the VRR craps the sheets. Consistently. I bet the charging system is killing it.. This bike is a blast to ride, but she loses a lot of shine due to this electrical issue and how often she leaves me walking down the road. Speaking of which, does anyone notice their bike being damned hard to push even with all new wheel bearings and brake system? Mine is like pushing a car in neutral with a sticking brake…

By: John M Cox

John M Cox — Wed, 14 Oct 2020 00:15:51 +0000

Im not an electrical engineer but I konw that electrical resistance increases with heat. Heat is everything. An air scoop mounted somewhere else with a chamber and filter to filter out water and bugs would be prudent. Then a new rubber tube leading down to the cover. It would need a vent hold as well and the bottom of the cover is the logical place. I have a 1980 cb650c and have been considering this, have come back to this post many times over the years.

By: Trinity

Trinity — Thu, 07 May 2020 03:01:31 +0000

I have a 1981 Honda CB650C and having same issues, going to replace the 3 parts and check my headlight. If that doesn’t work I will resort to the vent idea i just hope someone posts a picture so I can see

By: Shay Maoz

Shay Maoz — Sat, 24 Aug 2019 12:19:53 +0000

This is one of the very interesting conversation. it is keeping alive over the years.
i own a Honda 1983 CB550sc, of course with electric problem. battery is not charged. once again, the stator looks damaged. it is so hard to find this peace, till i did found the following one who is manufacturing this parts.
https://ricksmotorsportelectrics.com
hope it will help someone.

By: Cosmin

Cosmin — Fri, 02 Aug 2019 18:40:15 +0000

Guys. I just finished my cb 650 ‘79 and i got my battery dead. There is a clear solution that works at someone and last ?

Thanks.

By: Ron Critchlow

Ron Critchlow — Sun, 28 Apr 2019 03:22:39 +0000

Great thread! To reduce heat build-up.. Has anybody tried switching out the unventilated alternator cover with a ventilated cover from a 1983 650sc?

By: Steven O

Steven O — Mon, 23 Jul 2018 16:55:33 +0000

How do I know which one of these to replace? the rotor, reg/rectifier, stator, or headlight bulb? 80 CB650

By: Reuben

Reuben — Fri, 29 Jun 2018 10:02:21 +0000

Thanks for posting this..these are the same charging problems i face on my 81 cb900f. It was hard finding a new rotor here in Kenya so i had mine redone,works perfectly but once in awhile something will come off inside the casing n snap the wires its either that or if you run the bike with the headlamp on the batt gets drained especially at low rpm..so most of the time i make sure everything is off unless am on a night ride bt still the original sealedbeam headlamp doesnt illuminate much as you have to be at high rpms to keep it bright so will also be changing that . I also recently noticed that my bike is having a hard time starting up once the bike heats up like the batt is drained meaning there is minimal or no chargin when heating occurs (could it also be a sign of a dying batt that needs replacing maybe?). Very helpfull with the vent idea thanks as i will sort the heating issue on the rotor side now.

By: Honda CB550 and 650 1983 – 1985 Clymer Owners Service and Repair Manual | Workshop Manuals

Wed, 06 Jun 2018 06:58:29 +0000

[…] 79-82 Honda cb650 charging problems – Chin on the Tank … Ok… this is where it gets tricky. The main thing that will go wrong with the charging system is the rotor. There are 2 different ways that the rotor will shit out: […]

By: Rob

Rob — Sat, 10 Mar 2018 17:29:23 +0000

Did everyone know that a Yamaha xs650 rotor fits cb650, and they usually cheaper

By: chis

chis — Sat, 10 Feb 2018 06:35:49 +0000

fought this same problem for 2 years. this charging system from cycle exchanged fixed it.

http://www.cyclexchange.net/DOHC%20PARTS%20pAGE.htm

By: Roger

Roger — Fri, 10 Nov 2017 19:31:21 +0000

I have a 1979 CB750. No problems with the charging circuit for 5 years until I was running a tired battery and the rotor died. Changed the rotor and then died again after one year. Everything ohms ok but no charge. Could RPM in addition to heat be a cause for early failure? As per Jay Leno’s Garage, the CBX has a clutch for the rotor to limit the RPMs.

By: John

John — Thu, 24 Aug 2017 15:17:35 +0000

My mistake, book says .4-.5 ohm between yellow wires to stator, i measure .6 ohm on mine, what’s da verdict? Rotor, vrr test OK. I can’t get my 14-15 volts at 4k on tach. Ideas? Best source for a stator, if I need? I’m in SV AZ, 85635.

By: John

John — Thu, 24 Aug 2017 14:03:25 +0000

I have an 82 650 Nighthawk with electric charging issues, stator tests at .6 ohm between yellow wires and book says SB .3 to .4 ohm, it appears I need a stator? Vrr and rotor test good. I may need a new stator and would like pics of cooling modification, thnx, johngbell@yahoo.com

By: Max

Max — Wed, 15 Feb 2017 03:58:53 +0000

Hey all checking back in. Well its been a ride. Stripped down rebuilt, measured and installed new seals a 79 cb 650. Re-jetted, pod carbed, 4 to 1 Mac. HAND TUNED LIKED A BOSS.

Enter in The electrical problems… Replaced the entire charging system, sometimes I can get out and back no problem other times it just dies. Readings are 4-6 on the rotor, battery tests good, new stator and rectifier. Enter in the head light, and removal of the blinkers.

Wanted to mention about the venting of the rotor, there is an oil plug in side of there and obviously you’re not going to want to get dirt and grime in there.

One thing that is not mentioned here that I have done is the additional oil cooler, which helps knock down the temp by about 30-50 degrees depending on the free air temp. Here is a nice little walk through on another great site: http://www.chinonthetank.com/2010/07/lockhart-oil-cooler/

Oh! Lastly YES you can just use the rear axle as a puller for the rotor. It’s legit and worked on my cb650 79’ here is a link: https://www.youtube.com/watch?v=yVU_RUE0c4o

Good luck to you all!

By: jason

jason — Tue, 24 Jan 2017 13:09:21 +0000

I’m glad to see this thread stay alive over the years; I mean–glad as I could be for any of us fighting with our cbs. I’ve experienced every facet of electrical nightmare described herein with my ’82. I’ve replaced every component, too. Thanks for the bulb link. Also, I found a replica wire harness on partsnmore, and I’m going to give that a shot…just because shit gets old. Anyone have any experience with this harness (part # 73-0930)?

By: C.Rama murthy

C.Rama murthy — Fri, 21 Oct 2016 04:07:26 +0000

Your problem basically may be too much heat being generated internally in the rotor’s electromagnet. Your work of moving exhaust pipe away removes any doubt of the hot air blast heating this up.You can calculate the amount of electrical power dissipated in the rotor circuit’s resistance of 4 to 6 Ohms.It is VXV/R or 13.6X13.6/6 approximately 31W, dissipated as heat.In other words you have a hermetically sealed 31W heater in your rotor continuously heating it up. You can confirm this by measuring its temperature soon after a long ride.In that case, you have to reduce the rotor current while maintaining the ampere turns balance so that the magnetic field generated will not be reduced. This can be achieved by rewinding your rotor by a thinner wire(more turns), which increases the resistance, reducing the dissipated power.Some alternators have a way of regulating the voltage by reducing the field current by electronic circuitry which results in a constant 13.6V despite increasing speed and increasing (unregulated)alternator voltage. In case you are aware of such a control scheme,reducing the field current by adjusting the setting in electronics may be a possible option. An expert who knows about the regulating mechanism (if it is not potted) can help. If rewinding is not possible, you should plan to couple the heat generated in the copper wire to the case, say by smearing some heat conducting adhesive, which holds the wires and also conducts away the heat, improving the situation.I am no expert in these vehicles but just know a bit about electrical aspects and thought letting you know the source may help you solve it in a better way if the issue still exists.

By: Federico

Federico — Mon, 03 Oct 2016 07:45:52 +0000

@greg arnold Sorry for bothering you,
I was reading about the air scoop for the Honda CB 650 rotor. Do you have a photo of how the scoop is made?
Thanks a lot for the help!! federicobarazzoni@gmail.com

By: Lorenzo

Lorenzo — Mon, 26 Sep 2016 14:34:38 +0000

Hi All…

It seems that I’ve got the same problem. No one has an image of the air scoop?

Thanx