1990 K75 RT troubles

1990 K75 RT
Battery 28 months old, kept on tender.
So last Sat Am I go to start my K 75. The ign. key seems really stiff, bound up really and takes a few tries to get it to turn on.
I go to start it and it seems the battery is really low, almost dead, I jump it off my van and take off.
1/2 hr later I stop for gas and it wont restart and the starter relay sticks on.
I disconnect the ground lead and reach in with a screwdriver and tap the starter relay and get it to open.
I bump start the bike and head home early.
I get home and put a VM meter across the battery and go for a spin. 13.4-5 v. I let it sit and battery stabilizes at 12.8v
Key is still stiff but it turns and bike starts fine.
Battery seems good to me.
I pull my ign switch and clean it yesterday and it works much better now. For those in the know, could a gummed up ign switch cause this seemingly low battery condition?
Battery has sat for 48 hrs now and reads 12.7 v.
Thanks in advance
Nick
Ps I'm getting good at pulling that switch out now and cleaning it, whole procedure was performed in 40 mins.

Connect a voltmeter across the battery and take a reading while cranking the starter. If it drops below 12v while cranking it’s suspect. Or, you can take the battery to an auto parts store like Autozone and have it load-tested. If the battery checks ok the next thing I’d try would be to clean and de-oxidize all the connections between battery, relay, and starter as well as checking and cleaning all the ground connections.

Sticking of the relay contacts is usually caused by low cranking voltage, usually a bad battery or connections. I can’t speak to the switch as I’ve not seen one cause the situation you describe, but removing and cleaning the switch certainly cleared/cleaned the contacts.

Best,
DeVern

nickrides said:

For those in the know, could a gummed up ign switch cause this seemingly low battery condition?

Click to expand...

Nick,

Absolutely.

Take your voltmeter and put one probe on the back of #1 fuse (There are two holes on the back of each fuse. Either hole will do for this test.). Put the other probe at the ground bolt on the side of the transmission above the shift lever.

Turn on key and kill switch to run. Voltage should be within .5 volts of battery standing voltage across the battery terminals with key off.

DeVern
Its hard to get a battery cranking voltage as my bike starts so fast.
It seems I touch the starter and it lights right off.
But I'll clean the grounds and see what I find.
The nearest Place with a load tester is 80 miles away, but the next time I go down there I'll bring this battery with me.
Best
Nick

Let me run some tests after work today and I'll report back what I find out.
Thank you
Nick

Final Report
It was the Battery, a 28 month old SLA called a Mighty Max.
Don't buy one of those!
I looked in my Maint. log and saw my old Walmart battery, a Ever Start, lead acid battery before this one went 7 years, never fully died, just got a bit weak.
So I bought another one, 60 bucks.
All better now.
Funny how the Ign. switch got very hard to turn at the same time, opened it up, cleaned it, but it was clean to start with.
Bike is stored in a heated garage.
Oh well- its 30+ years old now, I still like to ride it!
Nick
1990 K75 RT

Glad you resolved the issue; enjoy the ride!

DeVern