Formerly intermittent start, now nothing- AND NOW SHE RUNS!

So, those of you who contributed to my 4th of july quandry may recall that I used to have panel lights on my XJ750 Seca, and a slight click when I hit the start button. Jumping across the terminals on the starter solenoid resulted in the starter turning over, so I ordered the new solenoid from Chacal, which came in 2 days(!) Bloody fast- thanks!

During the week I found that the bike seemed to lose charge- maybe I wasn't running it long enough on my "around the block" rides, or I have a weak (despite new) battery. In any case, I thought I'd throw the charger on and get the battery back up to snuff. Now I have nothing when I turn the key in the ignition- like the ignition wasn't even attached to the bike. I tried again to charge it, after gettting a 8.something volts read across the battery terminals, and now have less than 5 volts.

SO- battery voltage dropping, despite trying to charge; no response from the panel when I insert and turn the key; Fuses have been checked and appear to be un-blown (complete?). I've ordered the new fuse block, out of superstition, but am now wondering if there isn't something else I can be looking at in the interim.
Anyone?

TIA>>>. :?

 

Re: Formerly intermittent start, now nothing.

Yep, sounds like something is draining the battery. Do you have a digital volt/ohm meter with a 10 amp setting? I can tell you how to track down the draw... assuming that's what it is, of course.

Also, you'll need to unhook and recharge that battery.

 

Re: Formerly intermittent start, now nothing.

Did you check the length of your Alternator Brushes.

Nothing will kill a Battery faster than Alternator Brushes that are worn-down past their Service Limit.

Not only does the Alternator become at risk for the short brushes arcing and burning their circular contact points on the Rotor ... but, the high resistance can't provide enough current to satisfy the system requirements to charge the battery while the bike is running.

The bike draws current from the battery which isn't being charged and eventually there isn't any power in the battery to run the bike ... let alone be even close to the amps it needs to run the starter.

The battery just goes dead and the bike gets just as dead.
Not even a click.

 

Re: Formerly intermittent start, now nothing.

Unhook that battery and try to chargr it. If won't hold s charge exchange it under warranty. I had one of mine go south that way.

 

Re: Formerly intermittent start, now nothing.

what is a realistic mileage "life expectancy" for alternator brushes? The book says 10K Miles but is that overkill?

 

Re: Formerly intermittent start, now nothing.

Thanks guys- I've got this morning on my own, and will delve into things more deeply.

1. Remove battery from case, check fluid levels, charge
2. pull alternator and check brush length
3. Check for short (ugh).

There are parts (indeed, most) of this bike that are in great shape, and so I'll muddle through the electrical. While I'd rather not start my motorcycling experience learning the ins and outs of 80's era charging and starting systems, I guess it's better to know than to not know...

 

Re: Formerly intermittent start, now nothing.

These you might find handy...

 

Re: Formerly intermittent start, now nothing.

Gamaru-

Thanks for the images. You keep giving me great information that saves me from having to guess. I really appreciate it, and hope sommeday that I can pass some good bike karma back onto you (or, more likely, more newby than I). I am, hopwever, going to wait to crack the alternator case until I've eliminated the obvious things.

I decided to not trust my ancient battery charger (my charger has seen better days- think 1960 something) and went out and got a new one, along with a new battery, as I think it likely that the old charger trashed the newish battery on the bike . Rather than dive into the electrical I thought I'd eliminate the easy stuff first. So now I'm sitting down for a cycle of "wait for the battery to do it's chemical thing, then put it on charge" and in the meantime I'll clean my shop, which has gotten trashed over the first half of the summer with other projects coming in.

So, off to clean the shop. Have a great Sunday, all!

S-

 

Re: Formerly intermittent start, now nothing- AND NOW SHE RU

Just to follow up-

New solenoid installed;

Old battery charging attempt failed with old charger;

New battery charged with new charger- Installed and the bike starts right up. Run bike (OK, quick ride throught the neighborhood), park bike, turn off. Put away tools and try again- Bike still starts right up.

I know that I may still have a (dis)charging problem, and will monitor that closely- I've become familiar with my VOM once again. If I continue to see precipitous discharge then I'll take Gamuru up on his offer to help me go through my system to find the short, and check the alternator brushes as well.

In the meantime I'm treating this incident as one of those compounding failures things-
I drained the battery putting the bike in the park position and leaving the key in the ignition;

I only partially charged the battery using my antique charger, and likely hammered the battery charging too fast;

I had a wonky starter solenoid that was causing a drain on the batttery with repeated attempts to switch a failing solenoid.

Sound probable?

Thanks again to all answerring my questions. I'm sure I'll have more. :wink:

 

Sounds about right... Time will tell.

 

Re: Formerly intermittent start, now nothing- AND NOW SHE RU

from what you've described your battery was toast, and you have fixed it. Keep us posted, please.

 

Re: Formerly intermittent start, now nothing- AND NOW SHE RU

Time will tell, and I absolutely will let you all know how it goes.

I put the old battery on the charger last night, and the charger went through a 45 minute cycle of, uh, desulfination? (can't remember off hand the exact word), and then switched over to charge. I took the battery off the charger before it was fully charged, as I didn't want to leave it on all night, but will see what more it needs before checking the battery's vitals and seeing if I haven't resurrected it. At this point I'm treating it as a science experiment, and will keep the old battery on hand should I ever need another.

 

Re: Formerly intermittent start, now nothing.

Gee, those calipers look familiar. Can't imagine why...

:wink:

 

Gamuru, we need to sticky your photos!