Honda-SOHC
SOHC.co.uk Forums => CB650 => Topic started by: M0WBY on July 16, 2013, 08:01:51 PM
-
Hi
I am having charging issues.
So far I have replaced both parts of the alternator with good second hand parts that were fully tested before putting them on. At the moment it is charging I think. At tickover it has 12.4v across the battery. At 2.5k rpm it has 14V across the battery. At 5k rpm it has 14.8V across the battery. The battery seems to be charging. If I take the battery off the bike and charge it up overnight using my Optimate it charges and if left it stays charged up.
However when switch the lights on it drops a full volt and at tickover it only reads 11.4 across the battery. When switched off and back on again the battery behaves as thought it has dumped all it's power and won't hardly turn over. But if it is left for half an hour or so seems to recover. It does not do this with the lights off and behaves as though it is fully charged.
I don't know what to replace next. I am assuming the reg/rec is ok as it never goes above 14.8v and the manual says as long as it is under 15v it is ok.
I may replace the battery but it is less than a year old!
I don't know why the lights seem to run the battery flat so quickly.
Thanks for any help.
Cheers
John
>:(
-
Your charging voltages are spot on. I suspect that your battery is dead.
Sent from my iPhone using Tapatalk 2
-
With the lights on the engine needs to be over 3,500 rpm just to break even
-
Hi
So the battery has to hold a pretty good charge or in stop start traffic with the lights on it would go flat pretty quick requiring a jump start if it cut out for any reason?
Are Honda electrics really that crap?
I still think my battery is duff... I hope so anyway or my bike is getting traded in at the soonest opportunity.
Cheers
John
-
In the 70's, motorcycle charging systems (in general) were pretty crap - mainly because they couldn't build small, light, powerful generators like they can today.
With the lights on, no Honda of that age will charge at below about 3500 revs (as Bryan says). There's a revs vs charge table somewhere on .net - I'll see if I can find it.
So if you ride with your lights on and in stop/start traffic, your battery will run down.
If the battery is less than 100% it will go flat really quickly!
-
Found it! It's for a 750 but they're not that different.
http://www.sohc4.net/cb750-faq/indexphp/cb750-charging-rate-chart
-
Hi
I wonder how they coped in the US as you could not switch the lights off they even went as far as removing the on off switch!
I will have to rethink this as I always ride with the lights on. I think it may be time to sell it on and get something else.
Cheers
John
-
Hi all,
My 2ps worth.
Jap electrics were spot on for their time.Try the old 6v system shit.Its law here to have your lights on all day even though car drivers are blind and makes no difference they still pull out on you.I have never had any electrical problems even when I fixed them back in the 70s unless some bozo had messed with them.I have said this before you have a 70s bike not today's tech .You have to live with this or stay away from classic bikes.Talk to people with 70s cars don't you think they do not have problems.As for electrics the Italian,American and British bikes well what can I say CRAP.I ride mine maybe twice a week starts first time go for a ride get home battery's fine starts up on starter every time.Albeit it has a gel battery and not a poxy acid thing that does nothing but make your chrome look shit.
Keep this in mind
Cheers
Bitsa
-
Hi
I think I will have to get some night vision goggles...
Cheers
John
-
Hi
You have to admit it is a bit naff... I could ride my 81 GS750 with the lights on and never worry if it was charging the battery. In fact my 1977 Suzuki GT750 always had the lights on and never had a issue and if it did you could always resort to the kick start. Why o why did they do away with a kick start on this model when they knew charging was not up to much!
How much did you pay for a gel battery as I was under the impression they cost more than the bike is worth! LOL
Cheers
John
-
John,
I think I bought the gel battery of a German on eBay I think it was 45 euros and never regretted it been bloody good.On all winter and started straight up when I uncovered her.
In those days if I remember right the h/light bulb was only 35w don't think you can get them now modern ones are 55 or 60w so the charging system struggles a bit.Tommorrow when after a ride I will do some voltage readings for you lights on/off etc and will let you know what mine does.I do have a 35w fitted stored them up over the years.
Cheers
Bitsa
-
John,
Forgot to add my xjr1300 which the lights came on as soon as it fired up let me down more times than my Honda albeit through lack of use and try bumping that beast long live the kickstart.
Cheers
Bitsa
-
Hi
I think I have a 55W in the headlight.
Also one of my friends told me to check all the earths are good on it.
Cheers
John
-
Hi
Well the new battery came and it seems a lot happier.
I went for a ride on it yesterday but it started raining so being a fair weather biker I headed home.
Was not flat when I got back but the starter did sound a bit sluggish.
I am wandering if it is possibly the starter motor? It is alright when cold but when the motor is hot it sound a bit sluggish. Does this sound possible? I know the starters on these are well know for having issues. Could my starter cause a major amperage drain when it is warm?
Cheers
John
-
Yes as the resistance of the collected cr*p reduces with heat, most of the time(but not always) stripping the starter down and giving it a clean out with a lube of the bushes (NOT BRUSHES) will sort it out, we used to use a solvent called Armaclean to clean windings and commutators--don't know if its still about
-
Hi
I should be able to get it out with out too much bother won't I? I don't have to take the carbs off to get at the bolts holding the metal cover on will I?
Cheers
John
-
In all honesty I don't know for certain but i wouldn't think so, but then in my tool kit i did have a set of ratcheting ring spanners
-
Hi
This is a helpful article and just about sums it all up http://www.chinonthetank.com/2011/08/79-82-honda-cb650-charging-problems/
Quoted below - this would make a good sticky on the CB650 section!
"So, the 79-82 Honda cb650 has a shitty charging system.
I realized I’ve never made a post explaining in detail. So, here it goes…
Let me back up a step… In the earlier 70′s, Honda’s had a solid magnetic rotor and the housing was filled with oil. This was good. Honda’s rarely ever had charging problems… and if they did… it was because the regulator rectifier went bad, which was easy and cheap to replace.
In 1979, Honda tried a different type of charging system for 4 years. They went with a rotor which was wound up with wires inside of it, and the housing was not filled with oil. Shit would get hot. Real fuckin hot. Long story short… the rotor would often shit out. My rotor shits out about once a year.
Pic below. Left to right.
new rotor, new regulator rectifier, new stator
These are the 3 components in the charging system.
This is the way the used parts all sit on the bike. (I already took the rotor locknut off)
Where it all plugs in under the seat.
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:
1)
The wire on the rotor will physically snap as seen in the pic below. Once the wire snaps, no more charging at all… nothing. It will instantly start draining the battery. You’re not going to make it home. Battery will shit out in about 10-20 mins. Maybe less.
Or…
2)
The wires will visually appear fine, but the reading will be way above the spec 4-6, as seen below. Apparently that means there is an “open” in the circuit. Not sure what that means. Anyway… if this is the case and there’s an “open”, the charging system will still kinda work, but it will be erratic. It won’t directly start draining the battery… at least not right away. It will range from 9 > 12 > 7 > 10…. get what I mean… it will be erratic, rather than holding at the 13.5 – 14 like it should be. So… if this happens, you have a good chance of at least making it home before the cycle shits out completely.
Check out what the Haynes manual has to say about it all.
Getting the rotor off can be a pain in the ass. You need a “gear puller”. Pep boys has them. Make sure you back the lock nut out 1/4″ before trying to use the rotor puller.
Once you replace the rotor, stator and regulator rectifier, shit should be good again. 13.5 at idle and around 14 at 4K rpm.
Ok, so… you know how to replace the 3 items in the charging system.
Let me go into detail about other contributing things about why this charging system sucks balls.
I’ve come to the conclusion that heat is one of the main thing that breaks down the rotor. The stock header sits directly next to the stator cover, so I swapped out to a Mac 4-1. This eliminates extra heat on that side. I also installed an oil cooler to keep the engine a tiny bit cooler.
There are other factors that could make the rotor shit out. Not sure if i’m going to say this right, but if you have something in your wiring which is pulling extra amps, or the circuit isn’t flowing right, this could cause more strain on the charging system. So, basically, just make sure your wiring is the way it should be and your fuses are all good.
So, regarding my situation…
I’ve never had the charging system last longer than a year. I’ve done literally everything I can think of to prevent or offset the rotor shitting out:
- Every piece in charging system is brand new
- Different header/exhaust
- Oil cooler
- Rebuilt my entire wiring harness (check that out here)
- Double checked every connection numerous times
And the rotor still shits out on me. The aftermarket rotors have a thicker gauge wire to prevent it from shitting out, and over time… it still shits out.
I’ve researched this problem for the past 3 years, and there seems to be no real solution other than always keeping a backup aftermarket brand rotor and regulator rectifier on hand, so when your stuff shits out, you have a back-up ready.
One other thing to note is the stator rarely ever goes bad. Every time my rotor shits out,… it takes out the regulator rectifier with it, but the stator remains good. But… if you’re replacing all this stuff for the first time. Def make sure you replace all 3 just for a peace of mind.
Resources to buy the new parts:
- ElectroSport.com
- RegulatorRectifier.com
- ebay
- Dime City Cycles – for lower watt bulb
Good luck. This is the only flaw of this cycle. Unfortunately, it’s a big flaw.
UPDATE – MARCH 2013
I’ve been running all the new charging components as outlined above… with a lower wattage headlight bulb from dime city cycles, and shit has been good for over a year now. No problems. Also… I have a custom switch to keep my headlight off during the day. So… try the lower wattage bulb, but keep it off when you can. It seems to help in conjunction with all the new charging components… and oil cooler, and streamlined wiring."
-
If someone wants to convert that webpage into a Word document (with pictures), I'll be happy to include it. Maybe a bit of judicious language editing (?)
Otherwise I might have a go myself (but not right now)
Steve
-
Hi
Yes the writer does seem to have a potty mouth! Shame because it is actually a good article and I would love to see one on how to rig up a permanent digital ammeter to one of these bikes!
May have to rig one up myself! One wonders at what amperage when running is too high for the rotor.
Also given me some ideas may buy a 2nd hand alternator cover and modify it to allow some air cooling for the rotor like what they did on the 82 CB650SC!
At the end of the day I will only be delaying the inevitable I think!
Cheers
John