Topic: Red glowing clutch cable!

[Teddyhoeg1982]

I have been working on restoring this 1977 CB500. Did a few runs last year but never got it to run right. I just got done putting on a Kokusan electronic ignition and wanted to start the bike, but then saw that my clutch cable was glowing red hot when I turned over the starter. 

Guess my ground from the battery negative pole to frame and motor is not making connection and somehow I got ground to the starter through my clutch cable… Still trying to figure out how this could happen. I got the frame powdercoated last year, but seems I did not make good enough connection at the engine hanger bolt, so i will remove it and remove the paint.

[bryanj]

You need to remove the powder coat from either side of the mounting bracket so the cable contacts steel and so does engine case, you will probably have melted the loom up by the coils as well

[scottly]

There is a green wire in the main harness with an eyelet, that also needs to have a good connection to the frame. The connection may be under the seat near the battery, or at one of the ignition coil mounts under the fuel tank, depending on the model. Like Bryan mentioned, check for melted insulation.  

[Tracksnblades1]

Make sure your alternator still works..those bad grounds can cause havoc on circuits that aren’t designed for
High amperage…

Just wondering why your clutch adjusting nuts are on the same side of the bracket…?
Wrong cable..?

[Ozzybud]

Make sure your alternator still works..those bad grounds can cause havoc on circuits that aren’t designed for
High amperage…

Just wondering why your clutch adjusting nuts are on the same side of the bracket…?
Wrong cable..?

That's where the nuts were located from the factory. All my bikes and  bikes I have owned are in that configuration.

[bryanj]

That is a K3 500, its a rare model same as 550 but smaller bores, that is if it is a 500 and not a 550!

[dave500]

those nuts are correct,both on top.

[RAFster122s]

One serves as a locknut for the other nut.

[Oddjob]

That is a K3 500, its a rare model same as 550 but smaller bores, that is if it is a 500 and not a 550!

The 500 has a completely different clutch activation design. No external arm.

Not the 500K3, it has what is essentially a 550 bottom end with a 500 top end. I think they were using up old stock in the factory and fitted what they had left from 500 and 550 production runs. As Bryan says, quite rare, not that many made by Honda. Note the PD carbs and the CB550K3 style exhausts, not the tulip bulb 500 type. Never seen one in the flesh, might be the first I've seen an actual picture of, before that just parts book illustrations.

[bryanj]

That was what the 500 K3 was, i have somewhere a K3 parts book listed on front cover as 500/550 and in the last suplement for the 550 manual there are different carb settings for 500 and 550 both on PD carbs, as far as i can tell from parts book the only difference was barrels and piston kits

[rotortiller]

The best thing you can do with any main ground is to install it to the engine surface under a frame lug. That way the starter which has the largest draw has the best low resistance connection to the battery. No worries about paint insulating. I do not mess around removing frame paint with this option available.

[Oddjob]

I would recommend putting some drain tubes onto the carb float bowl overflow spigots, if the carbs overflow all that petrol will either corrode/affect the crankcase paint or worse drop down onto the exhausts and start a fire. Or both 

[HondaMan]

Got some marshmallows?

[Teddyhoeg1982]

I grounded the connections on both sides down to metal and gave them some WD40 for protection. The bike started right up! I have had quite a lot of problems getting this bike to run right last year, maybe this ground issue has been the problem. I am curious to take it for a run tomorrow and check.

[Teddyhoeg1982]

There is a green wire in the main harness with an eyelet, that also needs to have a good connection to the frame. The connection may be under the seat near the battery, or at one of the ignition coil mounts under the fuel tank, depending on the model. Like Bryan mentioned, check for melted insulation.

There is indeed a green ground wire at the coils - it seems fine. But I will take off the coils tomorrow and check that they also have good ground to the frame.

[Teddyhoeg1982]

Make sure your alternator still works..those bad grounds can cause havoc on circuits that aren’t designed for
High amperage…

Just wondering why your clutch adjusting nuts are on the same side of the bracket…?
Wrong cable..?

The bike would never charge, it is an issue I have not come to yet. Plan was to mound a modern combined rectifier/regulator and see from there. I do not believe it is the stator.

[willbird]

Many years ago a couple German guys came to our small Ohio town. They came to my dads machine shop to have some parts made. They could get talk English fairly well but one mentioned "this part gets warm when the machine is running". My dad asked "how warm?"....and the guy replied "red warm" LOL.

Bill

[Teddyhoeg1982]

That is a K3 500, its a rare model same as 550 but smaller bores, that is if it is a 500 and not a 550!

The 500 has a completely different clutch activation design. No external arm.

Not the 500K3, it has what is essentially a 550 bottom end with a 500 top end. I think they were using up old stock in the factory and fitted what they had left from 500 and 550 production runs. As Bryan says, quite rare, not that many made by Honda. Note the PD carbs and the CB550K3 style exhausts, not the tulip bulb 500 type. Never seen one in the flesh, might be the first I've seen an actual picture of, before that just parts book illustrations.

Here in Denmark these were quite popular. We never got the 550K models, but the 550F models were sold here. If you wanted a 500, in 1977 you would get this 500K3. Except for the lower CC, only other difference I have found from a 550K3 is the PD carb jets and needles which are specific to 500K3 and a headache to find. I had to buy a whole spare bike to get the right carb internals.

[scottly]

Was the clutch cable damaged by the heat?

[Teddyhoeg1982]

I would recommend putting some drain tubes onto the carb float bowl overflow spigots, if the carbs overflow all that petrol will either corrode/affect the crankcase paint or worse drop down onto the exhausts and start a fire. Or both 

Yes I have them lying around, just not mounted currently. Actually the engine case is raw aluminium, I never got it painted. Which I now regret, since I can see that over the winter it created quite some corrosion. Plan is to pull the engine out and get it painted, once I can confirm that everything runs perfectly. Now I though regret I never got it done when I had it out of the frame, when the frame was powdercoated.

[Teddyhoeg1982]

Was the clutch cable damaged by the heat?

It seems fine, but it got a different color. I will replace it, since it has probably weakened it - I do not want to end up stranded with a broken cable. 

[Teddyhoeg1982]

The best thing you can do with any main ground is to install it to the engine surface under a frame lug. That way the starter which has the largest draw has the best low resistance connection to the battery. No worries about paint insulating. I do not mess around removing frame paint with this option available.

This time I indeed mounted the cable directly to the engine surface, under the clutch cable bracket, instead of on top.

[bryanj]

From the factory it was on top BUT the bracket had no paint on either side at that point

[Teddyhoeg1982]

From the factory it was on top BUT the bracket had no paint on either side at that point

How would it be protected against corrosion then?

[bryanj]

It wasnt as such but the unpainted steel was tight against the alloy crankcase and the big cable terminal

[newday777]

From the factory it was on top BUT the bracket had no paint on either side at that point

How would it be protected against corrosion then?

Can you get this LPS-1 there? HondaMan says it is the best corrosion protection for electrical connections.

[BenelliSEI]

Funny story…. The early Honda Civics had a fairly small ground cable running from the top front radiator cross member to a stud on the valve cover. If you forgot to re attach it, the throttle cable became the ground. It quickly got red hot when the starter was engaged and would snap soon after that……. I only made that mistake once.

[RAFster122s]

Pulled a motor on a Volvo 122S and forgot to reattach ground strap at rear of head and it used the tube from the water temp sender to the gauge, the brass tube variety rather than an electrical sender, as the ground path. Discovered it after smelling the plastic backing of the gauge starting to deform an hour or so into running.

[MauiK3]

The lining in the clutch cable is likely pretty damaged.

[HondaMan]

I might mention that the 2 bosses on the frame where that clutch-cable-ground-bracket thing mounts should also be bare of paint so the engine's non-starter-related switches (Neutral and Oil PSI) can ground easily. Otherwise their lights can be dim when ON.

The way the OEM voltage regulator works is: it is fail-safe, but 50 years of life (being 40 years more than Honda planned on) have let the upper contacts inside it corrode a little bit. This is easily removed with a points file: just remove the top cover of the regulator and slide the points file in between the 2 upper contacts and give it a few polishing whacks (and clean the debris away). That's all it takes to restore most of the regulators to full performance.

Measure the 2 wires to the regulator's field coil to make sure they are actually connecting. The little bullet connectors are corroded by now on many of them, causing low (or NO) current thru the field coil. which reduces the charging power from an already-smallish alternator. While Hitachi rated the design at 120 watts, most only makes 90-100 watts because the battery voltage is typically on the low side (especially in the USA where the lights must always be ON while riding). Once below 11.8 volts or so, it can seldom catch back up unless the bike is ridden for a long time with the lights OFF, or the battery charged up for a time.