Idle Issue

wow  a CGS Hawk Tundra....it's gonna be a blast

http://www.aero-news.net/subsite.cfm?do=main.textpost&id=cb276598-dc57-41ab-80c0-6cb328eaffec

with the very best engine for it    I'm jalous..almost ?

Use the K&N oil sparingly - use just enough to get a very faint pink hue.  Apply the oil to the top edge of each ridge and let it wick slowly down into the folds. Too much oil tends to impede air flow and gum up the carbs.

4500 is WAY high for idle...  what does your oil pressure look like upon start up??

Don't even worry about oiling your air filters till your major problem is solved.  As Kevin Stewart said, take the filters off and look into the carb to make sure the butterfly valve is closed when the throttle arm is in the idle position (if it is NOT closed, the choke position hardly matters...)

When you do get to doing the mechanical sync, those idle stop screws should first be backed off the throttle arm completely.  It's all in the Maintenance Manual, Line, Ch 12-20-00, starting at page 26 (Jan 2020 edition).

Sure your tachometer is reading correctly? 4500 RPM during taxi would have me in the air pretty quickly, would be a very fast.

What are you using to measure the engine speed?

I'd wonder a bit about proper prop installation too, with an idle that high.