Sea level carb jetting

[Bill Hancock]

Yes this is yet another jetting question. My 400ex is totally stock except I recently added a Pro Circuit T-4 slip-on. My air box lid is on with the stock filter. I live in central Florida about 100 ft. above sea level if that. The temperature is usually between 80 and 95F this time of year. So far, I have changed my main jet from 148 to 155. This changed helped, but the motor sounded like it needed more fuel on top end. I currently have a keihin 160 main in and it runs great. I have made no changes to the pilot or needle. Here are my questions:

1. What is the proper way to adjust the pilot screw for idling?

2. I don't rely on plug chops because they never seem to work for me. Other than seat of my pants performance, what are other ways to determine when the motor is jetted correctly?

Hopefully there are some riders out there from Florida that can help me out with this headache. Thanks.

[Florida400EX]

Ha, lakeland 100 feet above sealeval, yeah more like 7 feet above, but anyways, try a 155 mainjet. Stock air screw settings should be fine.

[Bill Hancock]

The bike ran great with a 155 main. When I did wide open plug chops, the plug was white. Not burnt. The 160 main I have in it now feels the same as the 155. The plug is still white with the 160. I was told that plug chops are not very reliable. This stuff will give someone a headache. By the way, do you race FTR?

[Bill Hancock]

Florida400ex, maybe I exaggerated a little on the elevation. I do live a hill however.

[Florida400EX]

Well, I'm running a 160 mainjet, I have a Twin Air filter, no airbox lid, Pro circuit pipe and header, JE 416 10.8:1, and hotcam stg 2. Mine runs perfect now, don't bother with plug checks, you know it's perfect when you can barely hear a pop after WOT, too much backfire will be too lean, and none at all will be too rich. In about 2 weeks, once my shock return from k&k, if you want to meet me at thundercross on a saturday or sunday, I can help you get your quad dialed in.