Hey guys, when you set the idle gap you want to remove the air filter and leave whatever carburetor reducer that you are using in. It is not important that it is set perfectly to 1mm or 1.5mm (it can be .75mm, 1.25mm or what ever). The only reason that I recommend 1-1.5mm is because it is approximately the thickness of a credit card so it is easy for people to visualize how much of a space that is.

The primary reason for me having you guys check that is because one of the most common issues related to carb tuning that I run across especially with newer tuners is that they set the air gap (opening with the idle stop screw) way too small. It's not unusual to find guys complaining about idle problems and their engines tune being all over the board only to find that they have the air gap set open only like the thickness of a piece of paper! When this is done obviously very little air can flow through that super small gap, which means very little fuel is needed (remember it's all about the air/fuel ratio). This means that with very little air the difference between too little fuel (too lean) and too much fuel (too rich) becomes very small. This quite often leads to people chasing a tune, running the bottom way too lean, erratic idle etc. etc.

The easy way to avoid this, just make sure that you set an idle gap that allows a sufficient amount of air into the engine so that you can easily set your needles. Hence my recommendation of approximately 1-1.5mm or roughly the thickness of a credit card (again this does not have to be precise, just a ballpark). This is just a simple way to help avoid having your bottom end set too lean. Hope this helps explain things!

Regards,

Ron Hopkins
Werks Racing