1976 R75/6 Troubleshooting

[Jimijam]

The existing battery is shot, just by looking at it I can tell its out of commission, all the cells are wet, but a few are visibly corroded

[Ken in Oklahoma]

The existing battery is shot, just by looking at it I can tell its out of commission, all the cells are wet, but a few are visibly corroded

Hmmmm. OK. You know you need a new battery. That's money that's going to be spent sooner or later anyhow. So how about buying that new battery, installing it, and then seeing what you've got. No need then to even fool around with the charge pack. Now, with your new, known good, battery in place you can measure the voltage across the two battery terminals for different load conditions. You will also be able to tell for sure if your charging system is healthy.

For that you'll need a good cheap multimeter if you don't already have one. If not, as has been mentioned, it's about $4 at Harbor Freight. And in the past Harbor Freight has run lots of ad with a coupon to get the multimeter for free. Harbor Freight doesn't seem to be running the free multimeter coupon as often now, but likely they will again.

And if you don't know what to look for under various load conditions, we do. And we can tell you what you need to do.

Ken

[Jimijam]

Sweet, thanks.

[Jimijam]

Ok so when I hit the ignition, nothing happens. How do I troubleshoot the starter ?

[Jimijam]

Or who knows where I can find a step by step guide for replacing the starter?

[Jimijam]

I'm having some trouble getting the exhaust pipes off as well

[melville]

Yes, all sorts of stuff will be stuck! I've had good luck with the Haynes shop manual.

If the exhaust nuts are not coming off, cut a few fins off so you can get at the round bit of the nut with a Dremel tool. With a cutoff wheel in the Dremel, cut a groove parallel to the fins, deep enough to just *touch* the threads underneath. Then stick a screwdriver in the groove and twist. This should break the bond of the nut to the threaded stub on the exhaust port, and it should then spin off nicely.

You'll need new finned nuts, obviously, when it goes back together. The expense of these is a wee fraction of the cost of fixing the threaded stub on the cylinder head.

It's a big, powerful electric motor there, larger than what starts my VWs by a wee bit. For a quick starter test, you can lay a screwdriver across the small electrical connection on the solenoid and make it touch the nearer large post on the solenoid. If the battery has sufficient motivation and the motor is not seized, things should spin right along.

If that works fine, then move on to verifying that the happy electrons are going where they should. Again, the Haynes has good wiring diagrams if you're up to deciphering them.

[Ken in Oklahoma]

Ok so when I hit the ignition, nothing happens. How do I troubleshoot the starter ?

Jimijam, I'm not able to follow what you've been doing. Perhaps I've not registered something you've said. My impression is that you were going to get a new battery and see what happened. Is that what you did prior to your above post? If it is, there are several things that need to be checked out and the results reported back to us. I mean no offense, but reading your posts I get the impression that you're in a scatter shooting mode. Effective trouble shooting requires a methodical approach. There are many possible problems that, when you press the starter button, will result in "nothing happens".

Do you now have a multimeter? In the long train of "things that happen" there are many possible faults. A good trouble shooter will check them out in a planned manner. And electrical wiring, switches, motors, solenoids, contacts, and so forth all require the trouble shooter to know what's happening at each point. And that usually means measuring voltages. For example, to successfully turn the starter motor you will need:

1. A known good battery
2. The battery negative pole needs to be connected to a good battery cable which is connected to a good ground point.
3. The battery positive pole needs to be connected to a good battery cable which goes into the engine top cover and connects properly to a large terminal on the starter solenoid.
4. There will be a red wire which also is connected to the battery positive which will supply +12V to the rest of the motorcycle excluding the starter.
5. That red wire will find it's way through a connection or two to the ignition switch.
6. When the ignition switch is switched on more wires will be connected to various other places.
7. One of those places will be the kill button on the handlebar, which needs to be on.
8. With the kill button on pressing the starter button will apply 12V to the starter relay.
9. The starter relay will make internal connections which will allow 12 volts to go to a small terminal on the solenoid.
10. The starter solenoid will go clunk which activates the solenoid which makes the high current connection inside the starter cavity with the starter motor. (The starter solenoid also mechanically moves the starter gear into the gear teeth on the engine flywheel.)

I purposefully haven't talked about other things that will be happening such as feeding 12V to the ignition system

What I wrote down is a lot, and I didn't write it to confuse you. Many of those functions, if they aren't functioning, will result in what you're hearing, which is nothing. You're the only one who can find out which functions are working and which are not. And for that you will need a multimeter.

There are a lot of people here who can help you find out what's wrong. They will have different ideas for the troubleshooting process because people go about things differently. But by following various suggestions and reporting what you found, eventually we can arrive at where the fault lies.

Also we will need to know what lights are being lit on the instrument cluster with the ignition switch on and off.

Please don't take the above as condescending. Simply I don't know you and your capabilities.

Ken

[Airbear]

... a most excellent post.

Really Ken, bloody superb. What would we do without you?

O yeah, I remember - the forum nearly ground to a halt when you had your sabbatical.
A bundle of appreciation attached, steaming towards you, in Oklahoma.

[Ken in Oklahoma]

... a most excellent post.

Really Ken, bloody superb. What would we do without you?

O yeah, I remember - the forum nearly ground to a halt when you had your sabbatical.
A bundle of appreciation attached, steaming towards you, in Oklahoma.

Thanks, Charlie.


Ken