That's true, they called it a Quest up until 2004 then changed the name. They also had the 5 speed Traxter that year which I believe was a 500 (and also sold by JDeere as well)
I recall the 650 being a different model than the Traxter built by BRP. It had a CVT (belt drive) which is what the Quest 650 had. The Traxter was a 500 with a multi-speed gear transmission. Hope this helps.
Next test is to see if any power is getting to the starter motor when the button is pressed.
Best to use a test light, connect it to a good ground and probe the positive wire at the motor.
I see no reason why you couldn't run it without the cable connected. Usually the hour meter is separate and gets its reading from the ecm/ignition system.
It's just called a flywheel puller - they're different sizes and you need one that's specific for your motor.
They shouldn't be that expensive to buy, or else you can take it to your local shop that services these brands and get them to pull it for you.
Sounds to me like you have a starter clutch that has failed. To repair this requires removal of the ignition side case cover and pulling the flywheel off which needs a special tool to do so.
There is a one-way bearing likely attached to the back side of the flywheel. If this has failed there may be other parts involved that are worn. Not the easiest of jobs but it's usually possible to do without engine removal.
I've done this fix on a newer 300 Suzuki quad but I believe the older ones also used this style of starter system. Hope this helps.
If your Yamaha is cranking over fine but hasn't got spark, it's usually the stator. CDI modules rarely fail.
There are tests you can do with a multi meter on a stator but not on the module usually.
Those quads use a fuel pump in most models and can often fail. They can leak fuel and run really rich or do almost nothing and run dry - not always easy to notice the diff.
First thing to do though is change the sparkplug if you haven't already - it's a cheap fix for lots of quads!
There's only so much you can adjust, mainly the idle speed and idle/low speed mixture - there's a couple of screws involved. What's your issue, what do you think needs adjustment?
Nope, the decomp lever would only be required when pull starting - the electric starting issue may be just that your battery is low. Need to do a load test on it.