Riding in mud today the motor started making a pinging noise for a few seconds then died. tried to restart,acted like the battery was dying, now the motor wont turn over, i pulled the plug and then pulled on rope, and it still wont move. any suggestions?  

sounds like it's time to rebuild the top end.  it sounds like the rings have stuck/welded to the cylinder.

of course it could be that the rod bearing went out on the crankshaft side.

pull the head and the cylinder off.

once you get the head off and take the cylinder bolts out, if the cylinder doesn't want to come off then you know you cooked the rings due to lack of or poor lubrication. use wd40 and spray down into the cylinder and let it set a day or two.

if that's the case then all is not lost.  
you get to bore it out if the cylinder isn't scarred up too bad. (normally they
aren't i think the highest you can bore that engine is 80 over.) and that's alot for a set of rings to eat up.
if it can be bored you end up with more horsepower!
have it bored out (costs $35.00 to have it done here), buy an oversive piston kit to match the bore, with a new wrist pin. and a top end gasket set. (about $150.00 here.
and slap it back together.

oh and find out why it quit lubricating in the first place.

if it's rod bearing then you'll have to take it to a shop and have them press the lobes off the crank reinstall the bearing and then repress the lobes back on in the right spot.

(alot of money about $250.00 if you take the engine to them for the labor.  the rod bearing can run anywhere from 15.00 - 120.00 )
either way it's worth rebuilding it rather than junking it.  

Wolf1, question.  My 2002 Rancher is smoking bad.  Took it to a dealer.  Says I need to bore it and new rings which I can believe and is reasonable.  Also is telling me I need a new crank and rod assy,  Do you know of a way to get a rod bearing to save buying a whole crank assy and paying for the labor to repair?  Also how many hours do you think is appropriate to do the overhaul with the crank replacement and without the crank replacement.  Thanks.  

you can buy a rod bearing, but the counter weight of the crank has to be pressed off and back on. and it has to be timed right when it is pressed back on.
normally it costs more to do all of this than to buy a crank assembly with a rod and bearing on it.

reason being, they charge a fee to press it off and back on and time it. and then you have to buy the rod bearing.

check ebay i'd bet you could find a really good crank assembly.

reasonably i could change a crank assy in an hour, but the labor manual probably puts it at 1-2 hours.
and probably another 1-2 hours for the top end.
then .5 hours to dissassemble and .5 to reinstall.
if he is boring it himself, then add an hour to bore and hone.

i have a machine shop that bores cylinders for me, so i don't have to overcharge for boring, and i can work to get the rest of the engine ready for when the cylinder is ready. cuts "down time" in half, and the customer is happier.
if the cylinder has to be bored then you will need a new piston for the oversized cylinder. wether it's .20 over all the way to .80 over on some engines.
these repairs can be done fairly easily and are pretty routine.
HOnestly if it were me i would check into pricing the parts myself.

you can go to www.wiseco.com for the piston kits and most likely the crank assembly can be bought at wiseco as well.
but keep in mind if you decide to buy a stroker style crank then you'll have to trench the case so the rod pin will pass, and possibly gutter the cylinder skirt so the rod will clear it.

but price the parts yourself, most times the shop owner will raise the price of the parts to cover his warranty so you end up paying almost twice what you could have bought the parts for yourself.

myself, i don't raise the price of parts, if they are defective the companies i buy from are good enough to admit it and replace them.  as well i inspect every part before installation.
so what i am actually warrantying is my ability to put that engine back together correctly.
and the customer doesn't get gouged when he buys parts.

so total of around 5-6 hours from the labor guide. (6 if he is boring it himself)

realistically a focused tech could get it all done in about 3-4 hours,(tear down and reinstall without the boring time included.) but don't plan on your average shop giving you a break if it only takes 3 hours but the guide says 6.
alot of shops are trying to cover their overhead as well as make money.

Personally, I only charge what it actually takes, and the customer gets a detail of what is being done before it is done, and they can see that they are getting a good deal.
most times I flat rate the job and it comes out cheaper than taking it to a shop that is only charging by the labor guide, by the hour and overcharging for parts.

and iam not hiring a tech straight out of college at $8.00 an hour to build your engine for me.
the guys who work for me have years of experience and are worth far more than $8.00 an hour. and besides I do alot of the repairs myself. (i still enjoy it alot)

and if you can help it, try not to go to the dealer for repairs unless they are covered under warranty.

the dealers are the worst about jacking up the cost of parts and charging anywhere from $60.00- $80.00 an hour. find a good reputable repair shop with certified technicians.  

check out www.crotchrocket.com they have the cheapest honda atv factory parts online.