Topic: Electrical Problems in Sugar Land

[leekellerking]

I am experiencing electrical problems with my 1982 CB650SC Nighthawk (just hit 16,000 miles) which I'm attempting to troubleshoot.  If I ride more than about 5 miles, my fusible link blows.  If I put a new one in immediately, it almost immediately blows again.

I disconnected all the 15 amp fuses except the number 2 (from the left) one.  It still blew the main fuse.

My beginning question is this -- is the 1982 CB650 wiring diagram applicable to the 1982 CB650SC?

BTW, the batter appears to be good and the bike appears to charge okay.  I just have this short somewhere.

Thanks and bear with me.  I'm new to troubleshooting like this.

Lee

[leekellerking]

Still having problems, but I have a better idea (I think) of what is causing the blown fuses.  I find that if I unhook my regulator/rectifier, I don't blow a fuse (even a 15 amp fuse).  Of course, I also don't charge the battery, either.  Running the bike by charging on a battery tender at night, but that is obviously a short-range solution.

I replaced the Regulator/Rectifier and that did not fix the problem.  This weekend I am going to try and clean the reg/rec plugs and see if that helps.  Otherwise, I'm stumped. 

The Rotor seems to have the correct resistance (about 4.5 ohm between the two slip rings; infinity between either slip ring and the center ring).  No obvious corrosion on the stator wires. 

One thing -- I was unable to get the plug to the fusible link holder (connected to the solenoid) undone.  But if that was the problem, why would the bike run fine with the Reg/Rec unplugged???

Any ideas from the group mind?     

Help!!!!!

I am experiencing electrical problems with my 1982 CB650SC Nighthawk (just hit 16,000 miles) which I'm attempting to troubleshoot.  If I ride more than about 5 miles, my fusible link blows.  If I put a new one in immediately, it almost immediately blows again.

I disconnected all the 15 amp fuses except the number 2 (from the left) one.  It still blew the main fuse.

My beginning question is this -- is the 1982 CB650 wiring diagram applicable to the 1982 CB650SC?

BTW, the batter appears to be good and the bike appears to charge okay.  I just have this short somewhere.

Thanks and bear with me.  I'm new to troubleshooting like this.

Lee

[kslrr]

I am looking at my Clymer manual right now. There are color differences between the '82 CB650 and the '82 CB650SC Nighthawk.  When you say "fusible link", are you refering to the main fuse or something I do not see on the diagram?

[leekellerking]

The main fuse in the 82 is a 30 amp fusible link.  I have spliced in an inline fuse holder for an old-style glass and metal auto fuse.  Of course, those fuses blow just as easily as the fusible link (just cheaper and easier to change).

Something I forgot to mention -- the bike runs with the Reg/Rec hooked up but blows the fuse if I rev it to 5,000 rpm.  Seems to idle okay, but something is apparently spiking and causing a blown fuse. 

The bike runs fine with the Reg/Rec disconnected (except for not charging).  Tony Weeks at Oregon Motocycle Parts thinks it may be a bad conector.  I hope to check on that this weekend, but I am going camping with my two younger boys and will only have Sunday afternoon to do it.


Lee

I am looking at my Clymer manual right now. There are color differences between the '82 CB650 and the '82 CB650SC Nighthawk.  When you say "fusible link", are you refering to the main fuse or something I do not see on the diagram?

[kslrr]

Measure the voltage across the battery when @ 5000 rpm and when the fuse blows. The more we know of what is going on the better. Also make note of the lights dimming or becoming unusually bright.  The gears in my head are a spinnin'.

edit: I just discovered an error with the diagram in the Clymer manual for the '82 Nighthawk.

[NPHLYT]

BTW, the batter appears to be good and the bike appears to charge okay

The battery is only about 5 or 6 months old, I replaced it earlier this year from Batteries Plus. Once I get my office back together I will see if I can find the receipt (just in case). I have not found (or looked for) that spare fuseable link, I just got my power back yesterday (Monday).

It does sound like a bad connection, I know the only time that fuse ever blew on me was when the fuse cover came off while driving and the house key jumped the fuses. After I replaced that there was never a fuse issue.

[Hush]

Someone else had this problem this week on here, came down to removing all the fuses from the fuse holder and cleaning the sh*T out of them, apparently the corrosion build up on these fuses causes excessive resistance and the fuse pops!

KSLRR bet you discovered that the manual says  Br/W is Brown/Black eh ha ah I found that myself in the Clymer manual.

[kslrr]

KSLRR bet you discovered that the manual says  Br/W is Brown/Black eh ha ah I found that myself in the Clymer manual.

No, I found that the R/W from the Starter Solenoid becomes the R/Y to the Starter Switch and visa versa. The R/W actually goes to the Rect/Reg and the R/Y goes to the Starter Switch. Let's hear it for White Out!

[Hush]

Damn you are right!
Only for the 1982 CB650SC NIGHTHAWKE, the earlier models are OK.
But the colour codes for the BR/W is coded as Brown/Black, should be Brown/White.

[MJL]

Draining and charging the battery every day is bad, you will end up buying a new battery before too long.

[leekellerking]

Not blaming you, Jim.  There was no problem the first couple of weeks I had the bike, but the fusible link blew once (after about a 30 mile trip on the highway/freeway) and then a couple of weeks later it blew again.  After that, the problem got more frequent.

Now, I can duplicate it by revving the engine in the driveway.  (And that is after replacing the regulator/rectifier).

Lee

BTW, the batter appears to be good and the bike appears to charge okay

The battery is only about 5 or 6 months old, I replaced it earlier this year from Batteries Plus. Once I get my office back together I will see if I can find the receipt (just in case). I have not found (or looked for) that spare fuseable link, I just got my power back yesterday (Monday).

It does sound like a bad connection, I know the only time that fuse ever blew on me was when the fuse cover came off while driving and the house key jumped the fuses. After I replaced that there was never a fuse issue.

[leekellerking]

I already tried removing all the fuses but the one running the main electrical system (2nd from the left sitting on the bike).  It still blew the 30 amp main.  The only thing that stops that is to pull the plug on the Reg/Rec.


I will probably clean the fuse holder, anyway.

Lee

Someone else had this problem this week on here, came down to removing all the fuses from the fuse holder and cleaning the sh*T out of them, apparently the corrosion build up on these fuses causes excessive resistance and the fuse pops!

KSLRR bet you discovered that the manual says  Br/W is Brown/Black eh ha ah I found that myself in the Clymer manual.

[leekellerking]

I know.  But it is better than not riding.  I've ridden the bike every day since I bought it on August 15.  Currently, I am commuting 8 miles to work (one way) nearly every day and I like it!   

My next step is to go over the connectors again with a fine-tooth comb.  I have a "how to" sheet from Oregon Motorcycle Parts on checking and fixing corroded connectors and some dielectric grease.  Now I need some contact cleaner and some TIME. 

Going camping Saturday is not helping on the time thing, but my boys are excited about it.


Lee

Draining and charging the battery every day is bad, you will end up buying a new battery before too long.