'99 Big Boss 500
When I last used it 5mo ago it turned over fine and fired right up.
Now I only hear a single click when engaging starter button.
However on one of several attempts it did turn over but not enough to start.
I doubt its a ring gear problem because the flywheel is new.
Engine turns over puling chord.
But I never had much luck starting that way.

So I replaced the battery and solenoid and cleaned all those connections.
Made zero difference.

The connections to the starter look miserable to get at.
Any suggestions before I try?

 

The problem can only be battery, solenoid, starter or thick leads from battery, solenoid or starter. As you have fitted a new battery and solenoid this leaves only starter or leads, this includes earths, so check all of them before removing the starter. Usual fault on ATV starters is brushes, cheaper to buy than a starter and OEM starters are better quality than the Chinese aftermarket replacements, so I always fit new brushes to the old starter unless there is another fault.

 

I would check bendix could be stuck may try to get engine to rotate backward maybe by rocking atv backward and you said new flywheel which may have a little different teeth on flywheel which maybe mismatch with wore bendix teeth and got it jammed and just need a little lube because of atv been sitting that long without use