CB 650 major problem

[alpaca71]

I'm new to the forum so I hope this is the right place. I've been riding dirt bikes since I was little and decided to buy my first road bike about a month ago. My bike is an '83 CB650 with 32,000 miles on it.

My problems started within the first week, the battery would die with about three or four days of riding about two hours a day but after charging overnight it would be fine again.  I don't know much about motorcycles, but I suspect the problem is either a short, the stator not replenishing the battery or the regulator/rectifier not working correctly. When it wouldn't start the lights would at least come on, although dim.

I could live with the charging problem but today I made things much worse. I took a ride, maybe 35 or 40 minutes outside of town, much to little to completely drain the battery, and I stopped on the roadside to make a phone call. The problem was that I stopped on a hill, turned the engine off and put the kickstand down but forgot to put it in gear and it rolled over onto its left side and onto me. The weirdest part is that the bike never touched the ground it just rolled onto my leg as gently as a 450 lb bike could and after I picked it up off myself it wouldn't start again. The lights won't even turn on and nothing is visibly damaged or disconnected. After charging the battery there is still no response from the bike. I know some newer bikes have tip sensors that cut the engine if the bike goes over which can get stuck but I couldn't find one, the only thing i can think of is that something must have gotten disconnected.

I'd appreciate any help or insight I can get, I've really fallen in love with this bike and right now its just a pretty lawn ornament. Thanks. 

[TDodge7]

if the battery has died that many times then I would check the alternator output at the battery terminals with the engine running , and then if that's fine I would replace the battery . The battery that came in my 700s would start the bike and you could ride for a few days , and then it would finally wear down enough to not start the bike. There's a new battery in it now and it doesn't do that at all anymore , the old battery just didn't have the cranking amps it did when it was new and all it took was a start or two to run it down pretty badly from a fresh charge .

[SmokinFast]

if the battery has died that many times then I would check the alternator output at the battery terminals with the engine running , and then if that's fine I would replace the battery ....

+1

To check the alternator output, connect a voltmeter to the battery. With the engine running, the voltage should go up to around 14 as the RPMs increase.

Also, when the bike tipped it might have lost some battery acid through the vent.

[noahnsteph]

Well I know it doesn't have a tip over cut off swithch. When I spilled my 83 Nighthawk stayed running and even tried to run away from me as I picked it up off the ground.

My guess is something became disconnected. When I get no power it's usually either the battery cable is loose or the ignition switch wires aren't plugged in all the way.

[geemann]

if the battery has died that many times then I would check the alternator output at the battery terminals with the engine running , and then if that's fine I would replace the battery ....

+1

[alpaca71]

Thanks for the input, I'll find/check the ignition wires when I get home from work tonight as noahnsteph suggested and once I can get it running I'll test the battery like you guys described. Thanks!

[Laminar]

Main fuse. It's on the starter solenoid, and if stock, is a puny strip of metal. Replace it with an inline blade-type fuse.

[alpaca71]

Main fuse. It's on the starter solenoid, and if stock, is a puny strip of metal. Replace it with an inline blade-type fuse.

It looks fine, could there still be a burnt out connection somewhere near the fuse? Also how do I tell if the starter solenoid is bad?

[ariwhiteboy]

Chances are that battery is old and not taking a full charge, you can go have it tested by any chain auto parts store and if need be buy a new one.  The charging system is also a likely culprit here though. +1 on checking those voltage readings and replacing the fuse Laminar mentioned.

[Laminar]

It looks fine, could there still be a burnt out connection somewhere near the fuse? Also how do I tell if the starter solenoid is bad?

At rest with the battery connected, you should see +12V between ground and the red and red/white wires. The green/red and yellow/red wires are from the starter button. If 12V is placed across those terminals, the bike should crank.

To test, here's what I'd do. After pulling the solenoid off of the bike completely, I'd take an ohmmeter and test for continuity between the battery post and the two spades that connect to the red/white and red wires. Then I'd put 12V across the other two terminals (for red/green and red/yellow wires) and listen for the click of the solenoid activating.

[Laminar]

If you don't yet have a manual, you can check out the Clymer's manual on Amazon. You can actually search through and read the book before buying.

But if you're buying a manual, DEFINITELY go for the Honda version.

[Bad Boy]

Good advice here so far.  You should check the easy common stuff first.  If you are going to own an old bike a shop manual and multimeter is a must.  I would check things in this order:
Corroded battery terminals
Water level in battery
Voltage in battery engine off 12.4-12.8v, Battery fully charged with charger.
If you do not have a fully charged battery in good condition you can not test the charging system accurately.
Voltage in battery engine at 5000 rpm 13.5-14.5v
If not up to spec test the battery first at autoparts store.  If battery checks out good then follow charging system diagnosis in shop manual.

Most common problems are bad battery and corroded connectors.

[alpaca71]

Update:

I tested my battery with a voltmeter and had it load tested at advance auto and everything checked out fine. The connectors on top of the solenoid, red and red/white, were melting through the plastic connector but I tested the solenoid as laminar said and it seems good.

The people who sold me the bike gave me a clymer manual but the troubleshooting and electrical sections didn't tell me more than you guys have. A friend was nice enough to email me a manual so i'll go through that tomorrow and see if it helps at all.

Thanks for all the input, if I can get the bike running, I'll be testing the charging system next.

[Laminar]

Check the plug connected to your ignition switch. It's possible that the switch is bad and when you turn the key nothing happens.

[alpaca71]

So I pulled the ignition apart and found the cause, one of the small copper plates that completes the circuit when the ignition is turned to "on" was stuck all the way in but I managed to free it and get it sliding freely again.

[chas550sc]

You may want to go through your electical connections, clean/shine/replace melted or burnt ones and use dielectric grease on reconnection.

[ExTex]

As another electrical precaution, I replaced all of the fuses
and the brake-light bulb.  I also bought a new brighter headlight bulb.

The fall or next spring, you will want to replace all of the old fluids:
Brake & Clutch fluid:  Use fresh DOT 4
Rear gear oil:       Use 80w90 Valvoline semi-synthetic
Front Fork Oil:     Use Dextran ATF or 10 wt fork oil.

Check the tires for dry rot
Check the brakes for wear

Good News:  No coolant to change!   

Ride Safely
 

[alpaca71]

Great ill add that stuff to my to-do list this winter, tested the voltage at idle and at 5000 rpms and it went from 11.5 at idle to 21.1 at 5000. Does this mean the stator and/or rotor isn't doing what its supposed to? Or could the problem be somewhere else?

[ExTex]

Great ill add that stuff to my to-do list this winter, tested the voltage at idle and at 5000 rpms and it went from 11.5 at idle to 21.1 at 5000. Does this mean the stator and/or rotor isn't doing what its supposed to? Or could the problem be somewhere else?

   21 volts is way too high.  The voltage regulator must be bad.  

To replace the regulator, you have to replace the rectifiers also. They are a package deal.

I didn't buy the electrosport R/R, they are hard to mount.

Here is a good compant to buy from ... but a little high $
http://www.ricksmotorsportelectrics.com/results.php

I bought here: http://www.regulatorrectifier.com/catalog/1983-1986-Honda-CB650SC-CB-650SC-Nighthawk-Regulator-Rectifier


Do NOT run the engine or ride the bike with that high of voltage.
It will FRY your CDI ignition.... It happened to me.

[alpaca71]

oh man sorry i meant 12.1 thats a huge difference

[noahnsteph]

oh man sorry i meant 12.1 thats a huge difference

Welcome to my world. Seems like you have the same charging problem that I'm having with mine.   You should be seeing 14V or so at that high of an RPM.

[ExTex]

Yes, it sounds like a stator problem, but you need to measure the output of the stator coils or their resistances.
Based on my experience (I replaced the stator and then had to replace the R/R after high voltage ate my CDI),
I would buy the R/R in addition to the stator... and live happily ever after with a Scorpion AGM battery.

Anyway, Measure the resistances of the stator coils (about 1 ohm each) and the coils-to-ground resistances (infinite).
Or measure the AC voltages of the stator coils (R/R disconnected). They should produce about 70 volts at 5000 rpm.

Then check the diodes in the bridge rectifier.  No way to check the voltage regulator except that a good charging system will
top out at 14.5 to 15.0 volts.

Electrosport.com does have good information in their tech section on making these measurements, if you don't have it in your service manual.

Ride  Safely,

[alpaca71]

Great info, thanks ExTex. Ill update tomorrow after work when i can do some testing.

[alpaca71]

Ok so i checked the resistance between all three coils and they each gave me .8 ohms, the clymer manual says this reading should be between .4 and .6, and the resistance between the other two wires on the same connector which gave me 1.2 ohms, also supposed to be between .4 and .6.  I tested the R/R between the black wire and a ground at 2500 rpm and it gave me a voltage of 9.8, the clymer manual says between 14 and 15 is normal. I'm not sure what to make of this, I'm leaning toward the stator since i cant test the R/R unless the charging system is working properly.

Sorry to hear you're having the same problem noahnsteph, hopefully we can both get it resolved. I'd really like to go more than an hour outside of my town. lol. 

[noahnsteph]

Sorry to hear you're having the same problem noahnsteph, hopefully we can both get it resolved. I'd really like to go more than an hour outside of my town. lol. 

I hear ya. Fortunately my new saddle bags are big enough to carry a spare battery in each so I'm good to go for a longer ride. I just need to swap batteries after 100 miles or soo. At least until I fix the charging system.