Starter Problem?

I have a 110cc Chinese quad (Tao Tao motor). Problems since the get go. The latest seems to be the starter. The battery is charged. When I go to start it, it wants to crank, but then makes a whining noise...seems to be the starter. Am I correct? I found a dealer online that sells them for $45. Should I replace the entire part? I'm mechanically inclined, but not a mechanic.

Also...how tight should the drive chain be? And what are some suggestions for preventive maintenence?  

i wouldn't assume it's just a starter issue, it could also be a starter clutch problem, before ordering a new starter you can remove the old starter and bench test it, or remove the left side engine cover which you going to hafta remove it anyway to replace the starter and watch the starter and flywheel while trying to crank the engine over, if you decide it's the starter you can order one off of e-bay for around $30, they have two styles one the sits on top of the engine and one the sits below the cylinder, both styles fit the 50-125cc Chinese quads,
if you do not have a chain tension er for the drive chain grab the top center of the chain and pull up you need appox 3/8-1/2" slack. if it more or tighter then adjust accordingly.
preventive maintenance
buy and use a delran battery tender, cost around $25, if you use this you'll never have a surprise with a dead battery
use the fuel petcock and shut off the fuel every time when done riding for the day, when done riding for more than a day the drain the fuel out of the carb, this will prevent carb problems cost  O
also use a fuel stabilizer if the atv going to sit more than a week
i also add a little carb cleaner every other tank of fuel
change oil appox every 15-20 hours of use, these engines are air cooled and have no oil filters, need i say more
check all bolts and nuts before riding each time, exhaust nuts no matter how tight they are have a tendency to work loose  
07 prowler