Hi Lennyharp,
Here is the information I promised you. Some late 2007 and the 2008 models Whizzers have mushroom lifters. Sadly when Whizzer sent the information from my tests and prototype lifters, their vendor added their usual "lack of quality control to the equasion". Although the mushroom lifters solved the major problem of camshaft & lifter mismatch [either eats the camshaft lobes or destroys the lifters], they are poorly made. There are 3 major problems with the new mushroom lifters, 2 can be resolved and the 3rd makes them useless. Some of the lifters were cut undersize [approx. 5%] and can't be fixed, but so far the majority are OK [95%]. All the lifters I purchased from them are way too heavy, and can stress the valve train, and when they ground the base, most were not level. Both problems can be corrected with a drill press or a lathe, using a 3/16" drill. Simply drill out the center deeper [hollow out lifter]and stop approx 1/4" from the bottom of the lifter. Next put lifter in lathe or drill press and make sure the base is level, if not, use a file/sandpaper to level the base [I use a lathe and make sure the base is within .0002"]. Removing the lifters for service/modification is an easy task, but takes about 1 hour to remove, re-install, and adjust. Remove the side cover, pull the camshaft out [if it didn't come out with the side cover], remove the carburetor, remove the compression cover, loosen and remove the lifter adjustment bolts, let lifters drop down [I place a shop towel under them so that they don't drop into the oil in the crancase], re-work them, reverse the process to re-install. It is importand to advance the camshaft one tooth [counter clockwise], and set the lifter clearance to .006" intake, and .008" exhaust. When Whizzer made the extended manifold their vendor added the usual "lack of quality control" and drilled the holes at an odd angle, which means the manifold matches the intake better one way than the other. Simply rotate the manifold and see which way the manifold is closest to matching the intake port. It is important to discuss their choice of intake gaskets because most of the gaskets they use are too wide and creates a large gap [for the air/fuel flow] between the manifold And the cylinder. Order 2 of part number 16229 intake gasket and open the center hole to match the intake port, install the restrictor spacer [after you open the hole to match the intake port], then another 16229 gasket, then the manifold, then the carburetor. I use a thin version of the NE intake gasket between the manifold & carburetor, but isn't needed because the "O" ring in the carburetor mouth will seal against the manifold, I just put it there to make extra sure it never leaks. It is important to use the thin version because the thick gasket will hold the "O" ring away from the manifold and defeat the purpose. Now a few comments about the 22 MM carburetor, most if not the majority are jetted way too rich for most areas, and the earlier versions were sent out way past the workable range. The earlier 22 MM carburetor used a #95 main jet, then later they reduced the size to a #88, but in fact most [98%] need either a #82 or an #85 [and yes I have lots of #82 & #85 jets in stock].
Hope this information is helpful.
Have fun,
Quenton