1987 K75 won't crank when cold

[Nothsaw]

Live in AZ so have had no issues all summer long. Threw my leg over this morning in the 40F's and it wouldn't crank. Could my starter be bad? Any ideas? Thanks in advance!

[Laitch]

Engine oil thickens in cold weather; how much it thickens depends upon its grade. Cold engines will need full battery power to crank. If the crank won't rotate, check the battery terminal clamps and battery ground cable terminal on the transmission for tightness and clean surfaces. Your battery might be dead. Check its output; it should be above 12.6V. Give it a slow charge until fully charged if necessary then try again.

Thanks in advance not accepted. 

[Chaos]

I'm with Laitch, most likely a battery issue.  Starters go bad but not too often.  When mine died suddenly other weird stuff happened, like the tach needle rising when I pushed the started button as the engine did nothing.  I wrote it off as f**king magic and rebuilt the starter.

[The Mighty Gryphon]

When you say it won't crank is it because the starter motor won't turn, or is it because the motor turns, but doesn't turn the engine?  Are you just getting a click and a little bit of engine turning, or do you hear the starter whirring away?

I ask because there are different causes depending on what is or isn't happening when you try to start.

[Nothsaw]

Replaced battery. No cranking issues since.