Boxerworks.com

twist wrote:from what I can tell, this thing is useful for those who are tuning to a cam or using a carburetor such as a Mikuni that hasn't been jetted for the machine it's being used with. I think this is for use with a 4 stroke engine...

Relative to carburetted engines:
Dial-a-jet, flow-master, etal were never intended to be a carburetor "tuning tool".
Never intended to be a replacement for proper carburetor tuning.
Not a remedy for improper carburetor tuning or an excuse for a lack of tuning knowledge.

Any beneficial use of such a device will be predicated
by a knowledge of carburetor tuning & a well tuned carb ...
Best to think of Dial-a-jet, flow-master, etal
as adding ONE MORE jet to the carburetor system –
one that will also need to be properly adjusted / tuned.