Jetting is driving me crazy

[briano]

I just got done rebuilding an atc 110 motor and putting it in my 70 frame. The motor has a 123cc 10.5:1 big bore kit, Dico 3/4 race cam and a dg pipe. I also have a 26mm carb for it but I am going to have to make an intake for it. Trouble I am having is low and mid range, the top end runs good, I went up about 3 sizes on the main. I played around with the clip setting in the needle and it runs better with the clip raised, which would be leaner. The motor runs rich on the bottom, and seems lean in the mid, it runs the best with the mixture screw all the way in, which is richer correct. It starts up in 20 degree weather with no choke cold and then will idle but smoke a little, back the mixture screw out 1/4 turn and it will die. Mid range there is a sputter but once past that it runs like a scared cat. The stock carb is a 22mm and I am going to go to the 26 as soon as I can get my buddy to weld up an intake for me, I can't do aluminum yet with my welder. I just don't get how it could be too rich on the stock pilot with the mods that are done.

[shortline10]

Stock atc110 carb is only 18mm . unless your using a long rod stroker I think a 26mm is to big of a carb for what you have .

[briano]

I thought they were 22mm stock

[shortline10]

Nope a 22mm in def not stock for a 110 .

stock sizes for the following models = ATC90 16mm , atc110 18mm , atc125m 20mm , atc185/200 22mm , atc200x 24mm .





I thought they were 22mm stock

[briano]

Thanks for straightening that out for me, other than my little jetting problem, this thing is fast as hell. The cam and timing parts is just what I needed, thanks for the parts.