Boxerworks.com

1984 R100

So most of the time bike starts right up.

Once in a while all I get is a click and no cranking.

I try a few more times and then it starts normally.

Works fine all day then I get home and try and just get a click.

Starts fine with kick starter.

Had battery tested and is cranking above it's rating. Battery good.

Any thoughts? Starter relay?

Probably corroded pins on starter relay. Unplug and replug the relay a few times to clean off the corrosion.

Kurt in S.A.

So I cleaned the relay and terminal connections. I discovered that I had a new one in my parts bin, so I replaced it.

But I still have the same problem. It starts normally four or five times, then just a click.

I put the original relay back in and no change.

Solenoid?

That would be a much bigger project ):

When you refer to a click, do you mean the slight click of a relay or do you mean the much louder clack of the starter solenoid? If the former, then you are looking at the primary circuit of the solenoid... that is the relay (you already seem to have covered that one) the wiring and the activation coil of the solenoid. If it's the loud clack, then you can say that the solenoid is firing but that, for some reason the motor isn't turning. There could be a number of reasons for this (i'm assuming a standard setup with a Bosch starter). Things to check...

1. Check the starter mounting bolts. If these are slightly loose the starter can jam intermittently. The motor earth (ground) is also through the motor/casing interface so a loose bolt may mean the motor earth is suspect,
2. Are the big contacts on the rear of the starter solenoid tight, is the main lead to the battery sound, is the braid from the solenoid into the starter in good condition. Any of these could lead to a bad connection.
3. The contacts inside the solenoid can become eroded and burnt. The solenoid can be dismantled (needless to say, with the starter off the bike) and the contacts can be cleaned up if they're pitted or distorted. That being said, you can never restore eroded metal to the contacts so you may wish to consider replacing the solenoid.
4. Are the starter brushes moving freely and not worn excessively? A stuck or worn brush can fail to make contact intermittently. Dismantle and clean... replace brushes if worn.
5. Check the commutator of the starter. do this with a multimeter or test light checking that there is continuity between adjacent segments. Don't worry about the electrical resistance (unless there is some), it is so low as to be effectively unmeasurable with normal instruments. A commutator segment that doesn't show continuity is defective and will stop the starter from running if it happens to come to a stop with that segment under a brush. The only practical remedy is a replacement commutator (in reality, a replacement starter).

If you have the starter out and dismantled, it is always worth considering replacing the bushes, especially the nose bush. Worn bushes, while they won't stop the starter dead, will make it sluggish and potentially cause starting issues. It will also place extra strain on the battery reducing it's life.

OK, as usual what started out as a short concise answer has ended up as War and Peace but I hope it helps...

Rob

First thing I'd do is try and jump it from a car battery. Easy and might confirm the battery isn't that good.

Rule no: 1. It's always the battery.

Battery is good.Tested by a battery shop by two different methods. The guy would like to sell me a battery but says it is working perfectly.

Bike turns over quickly, with no hesitation, except when it doesn't.

My book says the starter on an '84 is the Valeo starter.

Before I start disassembling to get at the starter, I noticed that when I push in the starter button, there is a step (button hangs up on it's way through its travel) in the movement of the button. I can wiggle the button around and find a position where there is no step.

On Duanes site it lists the starter button as the 2nd most likely problem.

Because the bike will start properly 8 times out of ten, it's hard for me to keep testing it without feeling bad about abusing the system.

My understanding has always been that the Valeo starter came in with the monoshock models i.e. 85 model year October 1984 but I'm not going to be adamant about that, they are interchangeable anyway... apart from anything else, it makes little difference to the potential faults except that there is the additional possibility that the magnets in the motor have come loose... a fairly common fault of the early Valeo motors.Valeo motors can be repaired but it is often more difficult to find parts.

If you can hear the relay clicking or the solenoid clacking, you can pretty well eliminate the starter button from the equation. If it wasn't working you'd hear neither the click nor the clack...

Rob

I guess I'll find out who made it when I go in there. Thanx!

I had the Valeo starter fail on my 94 Mystic with a magnet becoming unglued. The symptoms were different. Initially, it turned over very slowly. After one or two more starts, it stopped working altogether. From the sound of your symptom, it sounds like the solenoid isn’t making contact to power the starter, or you have a dead spot. I’d take the cover off the top of the motor to gain access to the starter. Try hitting the starter button again to verify a no-start situation. Then validate that the clicking you’re hearing is the solenoid. If so, try jumping to the power going into the starter from the solenoid, not the battery to the solenoid. If it doesn’t spin, dead spot. If it does, solenoid.

According to this page:
https://www.euromotoelectrics.com/Start ... w-str1.htm

Doesn’t sound like you have a Valeo. They started in 1988.

Seth wrote: ↑Tue Jun 23, 2020 11:30 pm
According to this page:
https://www.euromotoelectrics.com/Start ... w-str1.htm

Doesn’t sound like you have a Valeo. They started in 1988.

I don't think that's right... my '87 had a Valeo from new (as far as I'm aware) and, yes, it did fail with displaced magnets. The symptons for this can vary. In my case, they were quite similar to those described by ZM. A few instances of the starter not working, then working again followed, eventually, by the starter motor locking solid. Later Valeo units (not sure of the date) have the magnets positively secured. I was able to source a later body complete with magnets and reassemble the unit. It's still fitted and working (fingers crossed) now.

Rob

Edit... reference to the parts lists shows that only the Valeo was specified for machines after MY '85. The Bosch unit was no longer specified. That isn't to say a Bosch unit couldn't be fitted to a post '85 model... I've done it... but it's most unlikely that it would have been fitted ex factory after that date.

Rob