HondaCB650

If you are resurrecting your's from a deep sleep, I am (trying) to bring mine back from the dead. Let me tell you my story:

I recently discovered that I find inner peace working in my garage. I restored a couple of old bicycles and a lawn mower, but wanted to try something bigger. I decided to try a motorcycle. 21 years ago, I sold my 1981 CB650 to my (at the time) father-in-law. He put in in a shed on his farm where it has sat up until about 2 weeks ago, when I acquired it back from him. Time has not been kind to it. It had a roof over it, but it was exposed to the elements from the sides. The pipes rusted away, the gas tank has large holes rusted into it, and the engine has corrosion all on the exterior surfaces. I started to give up before really even starting when I took off the carbs and everything I touched on them fell apart, but when I took some of the engine components off, I found the inside of the engine looked pretty clean. When I found a set of carbs on ebay for $50, I decided to see what I could do. I figured: My goal was to work on something, not to go bike riding, so this would accomplish that goal nicely.

Here's my first major problem: The corrosion caused a hole in the cover over the pulse generator. The generator itself does not look that bad, but there is some rust on the side. I bought a new battery and new plugs, and tested the ignition system by checking the spark from a plug against the engine block. It sparks, but just barely. How can I determine if it is the coils, sparking units, the pulse generator, or something else causing the low spark? I have a Clymer manual, but it is not much help in this regard. It does not show a way to test the sparking units (on which the backs are melted, but another thread suggested this does not mean they are bad) or coils, and simply says if they are not working, replace them.

Second problem: The bolt on the oil filter cover is frozen on. It broke my 12mm socket. I then rounded off the corners using an adjustable wrench, then completely destroyed them using vice grips. It will not budge. Suggestions? I've been pretty much soaking it all along in penetrating oil to no avail. Can I grind this bolt off and remove the cover this way?

PS: I can't believe there is a forum devoted to the CB650. This is awesome. I'm sure I'll have more questions.

I almost forgot! There is some kind of short in the ignition key component. I only get power when I wiggle the key just right. Clymer make no mention whatsoever about how to access this component. Any ideas?

Folsoml wrote:Second problem: The bolt on the oil filter cover is frozen on. It broke my 12mm socket. I then rounded off the corners using an adjustable wrench, then completely destroyed them using vice grips. It will not budge. Suggestions? I've been pretty much soaking it all along in penetrating oil to no avail. Can I grind this bolt off and remove the cover this way?

PS: I can't believe there is a forum devoted to the CB650. This is awesome. I'm sure I'll have more questions.

Welcome,
For the oil filter bolt, you can either weld a nut onto the top of the bolt and try again (the heat from welding it will help break it loose), or carefully grind the head off the filter bolt and remove the cover then remove the remainder of the bolt. Usually it is the lip of the bold head siezed to the cover that makes it stick. I have successfuly used the weld a nut on method. There are usually several replacement bolts available on ebay and I would reccomend the 17mm head bolt as your replacement.

Folsoml wrote:Here's my first major problem: The corrosion caused a hole in the cover over the pulse generator. The generator itself does not look that bad, but there is some rust on the side. I bought a new battery and new plugs, and tested the ignition system by checking the spark from a plug against the engine block. It sparks, but just barely. How can I determine if it is the coils, sparking units, the pulse generator, or something else causing the low spark? I have a Clymer manual, but it is not much help in this regard. It does not show a way to test the sparking units (on which the backs are melted, but another thread suggested this does not mean they are bad) or coils, and simply says if they are not working, replace them.

I think the best way to test is to replace them with known good ones one component at a time until you find the one that solves the problem, so if you can find someone near you with a running bike they may be able to help. Other than that, someone with more knowledge on troubleshooting those issues may be able to offer more helpful information.

Hey, at least the reflectors are in good shape! All kidding aside, that will be quite the project, but doable as long as the frame isn't rusted through anywhere. Good luck and bring that beauty back from the dead.

Welcome here!

Never seen a CB650 in that bad shape. It stood somewhere near the sea?
Much worse than phil's project here: viewtopic.php?f=2&t=177&start=45
Unfortunately his site where he described his progress seems not to be online any more at the linked place. Maybe worth to contact him to get the new URL if it should be still online somewhere.

Folsoml wrote: I recently discovered that I find inner peace working in my garage.
...
My goal was to work on something, not to go bike riding, so this would accomplish that goal nicely.

All right, so no need to tell you all this would make no sense for a CB650. On the other hand this is certainly cheaper than any official therapeutic measure. Nevertheless you could try to apply for an allowance from your health insurance.

For the ignition problem, start with cleaning up all related cables and contacts. As long as you have problems with the ignition lock switch, don't expect reliable operation either. Probably you need to open and clean the ignition switch from inside. I strongly recommend that because I know from own experience that an additional resistance in the ignition lock will rise the charging voltage which may cause further damage to electric components! The key needs to have a certain angle to separate the switch from the lock.

Don't forget the handlebar switches. Here the engine stop switch is first suspective for your ignition problem.
Another issue is the fuse box. Especially have a look at the rear side!

I'd say it is a good sign that you have a weak spark at all. Clean the related electric stuff and it probably will be fine. If sparks from both circuits (1+4 and 2+3 share one coil) are equally weak, your problem is probably mostly related to the common part (as written ignition switch, engine stop switch etc. ). Note that the ignition is only fused by the main fuse.

So far for now, please let us know your progress. Worth taking lots of pictures during this project.

Good luck!

Thanks for the answers! When I asked similar questions about a lawn mower I was trying to fix, I got a lot of, "Go buy a new mower" responses. Granted, that was on Facebook, not a mower forum.

Volker_P: How do I get the ignition lock switch off?

onepieceatatime: No one that I'm aware of with a similar bike in my area. Is anyone here close to Tallahassee, Florida?

carlsonjw: Frame looks good. I don't know how it survived when everything around it is gone.

Here it is today:

If you did not mention that you do it mostly for mental reasons, the answer here would be to get a better basis, too. In fact it seems even difficult to find a worse one while you have certainly several nice and running CB650C's around for a few $100.
You'll certainly pay more this way and the final result won't be better. But plays no role here.
The way I work in my garden is intentionally similarly unefficient for similar reasons.

The lock has been some years. I remember it was separable only at a certain angle position of the key. There were some (plastic?) clamps from the switch into the lock part that were blocked otherwise.
In there one or two bullets and springs and some metal parts.
Let me know if you don't get ahead, I will try to have a look in my parts box then.

Volker_P wrote:Welcome here!

For the ignition problem, start with cleaning up all related cables and contacts. As long as you have problems with the ignition lock switch, don't expect reliable operation either. Probably you need to open and clean the ignition switch from inside. I strongly recommend that because I know from own experience that an additional resistance in the ignition lock will rise the charging voltage which may cause further damage to electric components! The key needs to have a certain angle to separate the switch from the lock.

Don't forget the handlebar switches. Here the engine stop switch is first suspective for your ignition problem.
Another issue is the fuse box. Especially have a look at the rear side!

I'd say it is a good sign that you have a weak spark at all. Clean the related electric stuff and it probably will be fine. If sparks from both circuits (1+4 and 2+3 share one coil) are equally weak, your problem is probably mostly related to the common part (as written ignition switch, engine stop switch etc. ). Note that the ignition is only fused by the main fuse.

My spark seems to have degraded to no spark at all. I saw another thread that where you reminded someone to have both plugs in a coil to get a spark. I was not doing that, and was initially hopeful that this was the problem, but another try with both plugs got the same result.

I just returned from a nearby motorcycle aficionado who responded to a Craig's List plea for used parts. I brought back different coils, ignitor boxes, and a rectifier. Replacing my current parts one by one still resulted in no spark. Is it safe to say that it is the pulse generator, or is there something else I should check?

1st rule: don't buy parts as long as you know nothing. Motorcycle parts are expensive!

With that appearance, I just would assume some contact problem somewhere. You really need to disassemble everything and clean up every single plug and contact you can find (or get a new wiring harness). Makes no sense to do any electric diagnostics on a bike looking like that before. This is 30 year old tiny metal stuff stored unprotected probably not too far off the seaside for too long.
And ignition does not have to work properly as long as you have this ignition lock problem. Did you check out that emergency stop switch at the handlebars yet? Etc, etc...

BTW, I will try to split off your postings now as this thread will get too confusing with two bikes.

Volker_P wrote:
BTW, I will try to split off your postings now as this thread will get too confusing with two bikes.

Thanks.

I cleaned all the contacts along the wiring harness, but I've yet to get into the handlebar switches. I'll try that next. With regards to the key, could it still be the cause of no spark if the dummy lights come on and the engine turns over?

Now you have your own topic. Guess this may get a lengthy one.

If the engine turns over and you have lights, the ignition should do something in the sense that you can measure "something" at the spark plugs. With regard to the possible losses by all that corroded stuff it is hard to say if this is sufficient for a visible spark however.

You may be a genius. I tore the front end completely down to just wires. I cleaned every contact on connection on every wire on the bike--including the kill switch! I must say that the mud dauber nest that were inside this switch were some of the smaller ones I've found on this bike, but they were probably effecting the inner workings just the same. Anyway, I hooks the wires back up and gave it spark test and, voila', we have a good strong spark!

While I've got the front end broken down, I'm sanding and priming the forks and stuff.

Good progress!

Folsoml wrote:... I cleaned every contact on connection on every wire on the bike--including the kill switch!
...
Anyway, I hooks the wires back up and gave it spark test and, voila', we have a good strong spark!

As I told you: don't throw with parts but do your homework carefully. That's the way how these things usually work.

A rough surface of the fork tubes will kill the fork seals quickly. So be careful with sanding here. Probably again something you cannot recover reasonably. But in this case not that important when you don't want to go riding seriously.

CARB SETBACK: I had a rough day yesterday. I made my T vent and got it installed. I started to put the carbs on the bike and found that one of the throttle cable hook-up thingies was broken off! (Many of you may not be familiar with the highly-technical jargon I use. "Throttle cable hook-up thingies" refers to the place on the throttle where the very end of the cable connects.) This is on the carb set I bought to replace the original, which was frozen shut. So I checked my original carb set and found this one was broken also! (factory defect? {That's a joke--30 year old carbs}) Fortunately, it looked like it was still usable. Only the very end part was gone. I tore this carb set down and removed the piece I needed. Tore my new(er) carb set down and installed this part, and put it all back together (it was a lot easier to type this than it was to do it). I installed it on the bike and at least the throttle cables work. Unfortunately, I hook up a fuel line and fuel started dripping from somewhere on the number 3 carb. My next task is to take it all down again and figure out what's what.

Suggestions?

Good and sharp picture!
Carb overflow may be related to a sticky float. One may try to knock carefully with a piece of wood on the floater bowl to get it loose again. Might run in with time or not.
If you disassemble the carbs, don't mix up (moving) parts between them.

Guess you could like this now: viewtopic.php?f=4&t=5056