Here are the facts!
The best are the early 2005
The worst are current [not even close]
The list is too long to cover the engineering blunders on the EBay kits. It took Tiawan from early 2005 to 2009 to make a total mess out of a great motor.
The current offering brings you a motor with a very cheap "ball bearing" in place of the original needle bearing, a carburetor that is tuned for a ????, not a Whizzer motor, a world class engineered hunk of aluminum, now called the head, a flywheel with a pulley kinda attached [won't win any engineering awards], a cylinder that wasn't cured correctly so you can watch the headbolt threads "shear", mushroom lifters [soft, heavy, and poorly made], a camshaft timed incorrectly, etc.
Cost to upgrade most early motors under $200.00
Cost to upgrade current at least $350.00 and still won't be near as good as the earlier motors, ever.
I have personal experience with ALL series motors produced from 1999 to 2009. The sad part is the list of issues is so long with the kits offered on EBay it would take hours to list. It would be much easier to tell you what is right [a much shorter list].
The last 2009 motor I serviced needed the following......
A side cover with the original needle bearing, the left side crankshaft bearing, cylinder, head, head gasket, side cover gasket, tappet cover gasket, lifters lightened and re worked [not level], camshaft reset, pilot jet in carburetor, main jet in carburetor, modified oil breather, clutch bearing sleeve, replacement carburetor spacer [port off center by 1/4"], muffler insert [smashed center tube], and wrist pin. This motor had 49 miles on it before it stopped running.
BTW, Whizzer USA paid for most of the repairs trying to honor the warranty, and I applaud them for the effort.
Have fun,
